Comparison of Methods for Achieving the Zero Tolerance Standard for Fecal, Ingesta, and Milk Contamination of Beef Carcasses: Notice of Conference

SUMMARY: The Food Safety and Inspection Service (FSIS) will host a

conference to consider ``Achieving the Zero Tolerance Standard for

Fecal, Ingesta and Milk Contamination on Beef Carcasses'' on October 23

and 24, 1995, from 8:30 a.m. to 5 p.m., at the United States Department

of Agriculture in Washington, DC. The conference will consist of two

sessions on consecutive days. At the first day's session, participants

will discuss available scientific and technical data comparing the

efficacy of the methods for achieving the zero tolerance standard for

fecal, ingesta, and milk contamination of beef carcasses. Participants

are invited to make presentations regarding this scientific and

technical data during this first session. At the second day's session,

participants will discuss relevant public policy issues, including

public heath, regulatory, and economic issues.

The input provided at this conference will be taken into account by

FSIS in deciding whether to approve any methods in addition to trimming

for achieving the zero tolerance standard.

ADDRESSES: The conference will be held at the U.S. Department of

Agriculture, in the back of the South Building Cafeteria, (between the

2nd and 3rd wings), 14th Street and Independence Avenue, SW., in

Washington DC. Persons wishing to make presentations at the first

session of the conference are requested to submit in advance brief

statements describing the general topics of their presentations. Send

descriptions to Dr. William James, Director, Slaughter Inspection

Standards and Procedures Division, FSIS, USDA, Room 202 Cotton Annex,

300 12th Street, SW., Washington, DC 20250.

FOR FURTHER INFORMATION CONTACT: For further information, contact Dr.

William James at (202) 720-3219.

SUPPLEMENTARY INFORMATION:

Background

Effective prevention and removal of fecal, ingesta, and milk

contamination are among the most important steps companies must take to

ensure the safety of beef carcasses. Such contamination may harbor E.

coli 0157:H7, Salmonella, and other enteric pathogenic microorganisms.

FSIS has a zero tolerance standard for fecal, ingesta, and milk

contamination of beef carcasses, and is continually seeking the most

effective, scientifically supportable means of implementing this

standard.

The policy of FSIS has been to require the physical removal of all

feces, ingesta, and milk from beef carcasses by trimming. Before

February 1993, however, ambient temperature washes were sometimes used

to remove small flecks of contaminants. Use of ambient temperature

water washes for this purpose varied across the country and among

inspection personnel. A distinction between flecks of contamination as

to their source was not always made, i.e., determinations were not made

about whether flecks were fecal contamination or rail dust, and, in

some localities, whether they could be removed by washing.

In February 1993, after an outbreak of E. coli 0157:H7 in several

Western States, FSIS reinforced that trimming was to be the only means

of removing feces, ingesta, and milk contamination from beef carcasses.

The trim-only policy was based on the judgment that trimming was more

effective for removing fecal contamination than alternative approaches.

At the time, there were no scientific data available to the Agency

comparing the efficacy of trimming and alternative procedures.

Trimming, if performed properly, is an effective means of

physically removing from beef carcasses the visible contamination and

any accompanying microbial contamination. A primary conceptual

advantage of trimming over ambient temperature washing is that it

physically removes visibly contaminated tissue (which is more likely to

be microbiologically contaminated) rather than relying on a wash to

remove bacteria that, depending on the circumstances, may be firmly

attached. Also, trimming, when properly performed, is presumed to have

less potential than ambient temperature washing for spreading

contamination to other parts of the carcass. On the other hand, if

trimming is performed incorrectly, it has the potential to cause cross-

contamination as the knife moves from areas contaminated with bacteria

to newly exposed uncontaminated areas. The effectiveness of trimming

also depends on the skill of the operator in visually detecting and

effectively removing contamination, while avoiding further

contamination by handling the carcass during this process.

Strict enforcement of the policy requiring that trimming be the

only means to achieve zero tolerance, following the 1993 E. coli

0157:H7 outbreak in the Western States, was also based on the Agency's

need to directly and aggressively remove any potential source of

pathogenic contamination. FSIS believes that strict enforcement of the

trim-only approach was appropriate, based on the information available

at the time.

Since 1993, numerous other approaches to removing contamination

have been devised and studied to assess their potential as effective

alternatives or supplements to carcass trimming to achieve the zero

tolerance standard. FSIS is now considering whether to permit the use

of some or all of these alternative approaches. The following material

reviews current scientific data concerning different approaches to

achieving the zero tolerance standard for fecal, ingesta, and milk

contamination on beef carcasses, as they would apply under commercial

conditions.

Data Review

I. Condition of the Animal on Arrival at the Abattoir

Any discussion of the sources of pathogen contamination on beef

carcasses must consider animal husbandry practices and the farm

environment (Hancock et al., 1994), the possibility of cross-infection

during transport (Gronstol et al., 1974 a, b), and

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lairage of the animals before slaughter (Anderson et al., 1961; Grau et

al., 1968). The practice of regularly cleaning and disinfecting

transport vehicles and holding facilities reduces the level of

bacterial contamination in the environment and decreases the risk of

pathogens being spread between live animals (ICMSF, 1988).

Soil, feces, and moisture present on the hides and feet/hooves of

animals entering the slaughterhouse pose a considerable challenge to

hygienic slaughtering practices (Troeger, 1995). Seasonal and

geographical factors, together with animal management systems, have a

tremendous effect on the cleanliness of live animals presented for

slaughter.

Although it would be desirable to exclude grossly contaminated

animals from the slaughterhouse, Mackey and Roberts (1991) concluded

that such an action could be difficult to rationalize and enforce. Data

from Finland, however, indicate that exclusion of cattle carrying

excessive loads of soil and manure can be accomplished, with resulting

improvements in meat hygiene (Ridell and Korkeala, 1993). As a result

of imposing regulations requiring that excessively dirty cattle either

be slaughtered at a ``casualty'' abattoir or processed separately at

the end of the day using extra care (with any extra costs being

incurred by the farmer), the number of ``excessively dungy'' animals

presented at slaughter in Finland has decreased dramatically. Exclusion

of grossly contaminated cattle is deemed justifiable since such animals

yield more highly contaminated carcasses, even when slaughtered with

extreme care and using reduced line speeds. Carcasses from

``excessively dungy'' cattle had, on average, 5-fold more

microorganisms per cm\2\ than carcasses from ``control'' cattle despite

the added precautions.

Attempts have been made to clean live animals following arrival at

the slaughterhouse. In general, however, these efforts have not been

regarded as effective (Empey and Scott, 1939; Roberts, 1980). Though

Empey and Scott estimated that a cold water wash reduced the bacterial

levels present on cattle by approximately one-half, such treatments

have to be applied in such a manner as to restrict later potential

microbial growth on a wet hide and reduce practical difficulties

associated with handling wet, slippery hides. These investigators also

conducted small-scale experiments on the effects of hot water and

chlorine on microbial loads of hide-on cattle feet (not live animals).

While chlorine showed some potential, application of hot water was

thought by the authors to have practical limitations for live animals

as water temperatures of 75 to 80 deg.C were necessary to achieve

significant microbial inactivation. Animal welfare concerns and the

effect on meat and hide quality may complicate or preclude application

of such antimicrobial treatments to the live animal.

II. Bacterial Contamination During Slaughter

It is generally agreed that deep muscle tissue of healthy live

animals is essentially sterile (Gill, 1979, 1982; Zender, et al.,

1958). During slaughter and dressing procedures, the surfaces of

livestock carcasses become contaminated with microorganisms. The extent

of this contamination varies depending on the condition of the animal

upon arrival at the establishment and methods used during slaughter and

dressing (Roberts, 1980). Contamination of carcasses is undesirable,

but cannot be completely avoided, even under the most hygienic

conditions (NRC, 1985; Roberts, 1980; Roberts et al., 1984; Grau, 1987;

Dixon et al., 1991).

When meat is produced under hygienic conditions, numbers of

pathogens contaminating the surface of the carcass are usually small,

and the micro-flora consists primarily of saprophytic bacteria, such as

Pseudomonas. Results from beef carcasses sampled for pathogens and

other bacteria of interest, reported in Nationwide Beef Microbiological

Baseline Data Collection Program: Steers and Heifers, reflect low

numbers of pathogens contaminating the surface of beef carcasses.

Staphylococcus aureus and Listeria monocytogenes were recovered from

approximately 4% of 2,000 beef carcasses. Salmonella and Escherichia

coli 0157:H7 were recovered from 1% and 0.2%, respectively, of more

than 2,000 beef carcasses. Only 3.6% of the carcasses had coliform

counts greater than 100 colony-forming units (CFU)/cm\2\ (2.0 logs) and

6.9% of the carcasses had aerobic plate counts of over 10,000 CFU/cm\2\

(4.0 logs). Although raw meat containing over 10,000 CFU/cm\2\ of non-

pathogenic spoilage bacteria does not present a health risk, it is

generally considered aesthetically undesirable, has reduced shelf-life,

and is often viewed as having been produced unhygienically.

Good hygienic practices during the slaughter and dressing of

livestock are critical to safeguard the microbiological safety and

quality of meat (Empey and Scott, 1939; Ayres, 1955; ICMSF, 1988).

Adherence to good hygienic practices, however, does not preclude the

presence of pathogenic bacteria on the final dressed carcass.

Salmonella, E. coli 0157:H7, Listeria monocytogenes, and Campylobacter

jejuni have all been recovered from hygienically-slaughtered beef

carcasses (Stolle, 1981; Weissman and Carpenter, 1969; Chapman et al.,

1993; Loncarevic et al., 1994; Stern, 1981; Gill and Harris, 1982).

Feces, ingesta, and milk from infected cows may contain Salmonella,

E. coli 0157:H7, and other pathogens (Grau et al., 1968; Munroe et al.,

1983; Martin et al., 1986). Accidental carcass contamination with

feces, ingesta, and milk is thought to be the primary route by which

pathogens enter the food chain (Chapman et al., 1993). Removing such

visible contamination from carcasses should reduce the risk to

consumers but is unlikely to produce pathogen-free carcasses.

Slaughter Floor Contamination

The main direct sources of carcass microbial contamination on the

slaughter floor include the animal (especially the hide and feet/

hooves), dressing equipment and tools, personnel and their clothing,

and the plant environment. Water is sometimes mentioned as a possible

source of microorganisms, but this association is largely historical

since contemporary abattoirs use exclusively potable water (or

reconditioned water of equivalent microbiological quality). Similarly,

the contribution of airborne microbes to carcass contamination on the

slaughter floor has been mentioned, but Roberts (1980) concluded that,

``air deposits only tens or hundreds of microorganisms per cm\2\ per

hour, where operatives and equipment carry tens or hundreds of

thousands--or even millions.''

Although some microbial contamination of deep-muscle tissues may

occur during stunning and bleeding processes when intact skin is

broken, thus allowing bacteria to enter the bloodstream, these actions

do not generally introduce significant numbers of bacteria (Roberts and

Hudson, 1986). The primary source of bacterial contamination of the

carcass is generally the hide (Empey and Scott, 1939; Ayres, 1955;

Newton et al., 1978; Smeltzer et al., 1980a). During the initial stages

of hide and leg removal, microorganisms present on the hide are

transferred to subcutaneous tissue by the skinning knife. Additional

microbes may be directly transferred to the subcutaneous tissues from

the hide when a loose outer flap of the hide contacts the carcass

surface during hide pulling (Mackey and Roberts, 1991). Contamination

may also be transferred indirectly from the

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tools, hands/arms, and clothing of workers (Mackey and Roberts, 1991).

A classic example is a worker holding the carcass with an unwashed hand

that previously had been in contact with the outer surface of the hide.

Studies have shown that workers handling hide-on beef carcasses are

more likely to have a higher incidence and prevalence of salmonellae on

their hands than are personnel performing other on-line tasks (Smeltzer

et al., 1980b). Similarly, knives and other equipment used for hide

removal are more likely to be contaminated with Salmonella than are

implements used for other operations (Peel and Simmons, 1978; Smeltzer

et al., 1980a). Grau (1979) found that Salmonella contamination was

especially likely to occur when a knife was used to free the rectum and

anal sphincter during hide removal. Studies have shown that knife

decontamination in hot water is often an inadequate means of

inactivating Salmonella and other bacteria on the knife surface,

usually because of insufficient exposure time (Peel and Simmons, 1978).

Greater than 10 seconds exposure was necessary for microbial

inactivation when a contaminated knife was dipped in 82 deg.C water.

Cross-contamination is reduced when knives and other implements are

frequently decontaminated, and hands, arms, and aprons are washed and

sanitized regularly (Norval, 1961; Childers et al., 1973; Peel and

Simmons, 1978; Roberts, 1980; Smeltzer et al., 1980a and b; de Wit and

Kampelmacher, 1982; Grau, 1987).

After the removal of hide, hooves, and head, most subsequent

microbial contamination is attributable to the hygienic practices of

the workers or technical errors, such as puncturing the animal's

gastrointestinal tract (Roberts, 1980). Knives and other equipment used

for evisceration are generally less contaminated than tools used for

hide and leg removal (Smeltzer et al., 1980a). The incidence of

Salmonella on beef carcasses, knives, and aprons increases at the stage

of evisceration, but to a lesser degree than during hide and leg

removal (Stolle, 1981; Smeltzer et al., 1980a). Thorough training and

careful evisceration practices (especially closing off the ends of the

gastrointestinal tract and removing the intestines from the body

cavity) are necessary to prevent carcass contamination with ingesta or

feces (Grau, 1987; ICMSF, 1988; Mackey and Roberts, 1991).

Microbiological contamination acquired during the slaughter and

dressing process of livestock is not spread evenly over the carcass,

and may be expected to vary between sides of the same carcass, between

different carcasses processed on the same day at an abattoir, between

carcasses produced on different days at an abattoir, and between

carcasses produced at different establishments (Empey and Scott, 1939;

Kotula et al., 1975; Ingram and Roberts, 1976; Roberts 1980; Johanson

et al., 1983). This variability can be due to a number of factors, such

as differences in dressing methods, worker skill, application of

washing or other carcass treatments, season of the year, and weather.

III. Attachment of Bacteria

The rate of attachment, growth, and multiplication of bacteria on

carcasses is dependent on the structure, composition, and water

activity of the exposed tissues, the acidity of the surface, the

temperature of air and the carcass, the bacterial strain, and various

bacterial attachment mechanisms (Lillard, 1985). The skinned ``hot''

beef carcass provides an ideal environment for bacterial survival and

multiplication. Surfaces of chilled carcasses, especially those that

have experienced significant dehydration, may be less attractive sites

for bacterial attachment.

The process by which bacteria attach to meat surfaces is believed

to consist of two stages. The first stage is where bacteria are either

attached by weak physical forces or freely floating in the water film

that covers the meat surface. The second stage is characterized by a

stronger attachment mechanism involving, in part, the formation of

polysaccharides over time (Firstenberg-Eden, 1981). This consolidation

stage is followed by colonization or growth of the microbes on the meat

tissue. Once attachment and colonization have occurred, it is very

difficult to completely remove pathogenic microorganisms from meat or

poultry surfaces by normal processing methods (Benedict et al., 1991).

There is considerable variability among bacteria in their ability

to attach to different surfaces. This is likely to be a reflection of

the different mechanisms (including pili, flagella, extracellular

polymers) used by different bacteria. It has been suggested that

bacteria from feces attach more strongly and in higher numbers than the

same bacteria grown in laboratory media or meat surfaces (Notermans et

al., 1980). Enhanced binding by bacteria present in feces may have to

be considered when evaluating the efficacy of carcass decontamination

treatments.

It appears that specific bacterial binding sites (receptors) exist

on animal cells. Collagen, in particular, seems to be a target for

bacterial attachment (Mattila and Frost, 1988; Benedict et al., 1991).

Notermans and Kampelmacher (1983) concluded that attachment cannot be

completely prevented by manipulating water sprays or baths through the

addition of chemicals or manipulating pH. Therefore, the only way to

absolutely prevent attachment is to prevent contact between bacteria

and meat. While bacteria are still freely floating in the water film,

they can be displaced using clean water (Notermans and Kampelmacher,

1983). Measures designed to block attachment should be applied as soon

as possible following contamination. Two points on the slaughter line

that appear to be likely sites for the application of carcass sprays

are following hide removal and following evisceration.

IV. Methods To Decrease Carcass Contamination

In addition to trimming as a means of removing bacteria associated

with visible contamination, bacteria are removed from carcasses by

several recommended methods, such as rinsing or washing with water

(both hot and ambient temperatures), either with or without one of

several approved food-grade organic acids (lactic, acetic, or citric)

or chemical sanitizers, such as chlorine. Each of these factors is

reviewed in the following sections for its relevance to beef carcass

decontamination.

A. Water Rinsing

Rinsing a carcass can remove physical contamination (dirt, hair,

fecal matter, etc.) to a varying degree, carrying with it some of the

resident microorganisms. As indicated above, interventions of this type

or others that physically remove bacteria should be used as early as

possible after likely introduction of contamination (e.g., after hide

removal) to prevent or retard bacterial attachment and growth. Various

factors associated with rinsing carcasses can be manipulated,

increasing the effectiveness of this approach. Major factors include

water temperature, water pressure, line speed, and method of

application (Anderson et al., 1979; Crouse et al., 1988). While

numerous studies have examined the efficacy of washing techniques, most

investigations have been conducted under research conditions, and only

a few have directly evaluated effectiveness in production settings.

The use and timing of hot water (95 deg. C) application during

processing were investigated by Barkate et al. (1993) to determine

effectiveness in reducing the numbers of naturally

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occurring bacteria on beef carcass surfaces. They found a 1.3

log10 CFU/cm2 reduction in aerobic plate counts (APCs) for

samples sprayed with hot water before the final carcass rinse as

compared to a 0.8 log10 CFU/cm2 reduction in samples sprayed

with hot water after the final rinse. The fact that fewer bacteria were

removed from the samples sprayed with hot water after the final rinse

may have been due to the length of time (approximately 15 to 20

minutes) that elapsed before hot water was applied. In this connection,

the authors interpreted Butler et al. (1979) as indicating that the

time lapse may have allowed more bacteria to become attached and more

resistant to the lethal effects of hot water.

Anderson et al. (1979) reported that under laboratory conditions,

bacterial counts were reduced 1.0 and 2.0 log10 CFU/cm2 when

beef plates were treated with cold (15.6 deg. C) and hot (76-80 deg. C)

water, respectively. During subsequent storage at 3.3 deg. C, the time

to reach microbial spoilage (108 CFU/cm2) was 6 days with cold

water and 12 days with hot water. The untreated controls took 7 days to

reach spoilage levels.

Smith and collaborators (Smith and Graham, 1978; Smith, 1992; and

Smith and Davey, 1990, and Smith et al., 1995) have investigated the

effectiveness of hot water (140 deg. F) washes versus a more commonly

used wash temperature (100 deg. F). Hot water was effective against

pathogens such as E. coli 0157:H7, Salmonella, Yersinia enterocolitica,

and L. monocytogenes. Quantitative studies assessing the effect of hot

water treatment on the survival of E. coli 0157:H7 indicated that

levels on artificially inoculated carcasses are reduced by 84-99.9%

(Smith, 1992; Smith and Davey, 1990; Smith et al., 1995) Other studies

have reported reductions in E. coli biotype 1 as great as 99-99.9%

(Davey and Smith, 1989).

Hot water sprays are most effective when the water film on the

carcass surface is raised to 82 deg. C (180 deg. F) for at least 10

seconds. If beef tissue is exposed to this temperature for more than 10

seconds, the surface of the fat and lean tissues can become gray to a

depth of about 0.5mm. These carcasses, however, regain their normal

color after chilling (Smith and Graham, 1978; Barkate et al., 1993;

Patterson, 1969). Carcass bloom, however, is permanently and adversely

affected if exposed for 20 seconds to temperatures above 81.4 deg. C-

82 deg. C (Davey, 1989, 1990; Barkate et al., 1993). Lower temperatures

applied for longer periods of time also have been found (Davey and

Smith, 1989) to permanently affect bloom.

Similar results have been reported by investigators worldwide.

Patterson (1970) sprayed beef carcasses with steam and hot water at

176-204.8 deg. F (80-96 deg. C) for two minutes, applying in the case

of water 18.9 liters to each carcass at a distance of one foot (25cm),

to determine the effectiveness of hot water in reducing carcass

contamination. Although some discoloration of the carcass occurred

initially, cooling for 24 hours restored normal color. Approximately a

log reduction in total plate count was observed; however, there was no

significant reduction in fecal streptococci. A differential in

bacterial counts between treated and untreated carcasses was still

evident after 48 hours of refrigerated storage. Smith and Graham (1974)

used beef and mutton samples inoculated with E. coli to compare the

effectiveness of hot water treatment, steam chamber, steam injection,

or washing with water at 37 deg. C (91 deg. F) on microbial levels and

carcass color changes. Water temperatures below 60 deg. C (140 deg. F)

produced no significant color change. As temperatures rose above

85 deg. C (176 deg. F), there was permanent and marked color change.

Very high temperatures of 95 deg. C (194 deg. F) for three minutes

changed the surface coloration to a depth of no more than 0.5mm below

the surface. Temperatures equal to or greater than 70 deg. C (158 deg.

F) produced a 2 log10 (99%) reduction of E. coli.

Water can be applied to a carcass, by either hand or machine, using

washing, spraying, or dipping. Hand and machine washing were compared

by Anderson et al. (1981). Hand-washed carcasses had reductions of 0.99

log10 CFU/cm2, while an experimental beef carcass washing

unit yielded a 1.07 log10 CFU/cm2 reduction, a non-

significant difference.

The angle of water impact has been shown to be an important factor

in bacterial removal. When water pressure is normal, a 30 deg. angle is

more effective at removing bacteria than a 90 deg. angle (Anderson

1975). When line pressure is increased, the angle degree is less

important.

Since bacterial attachment affects the ease of removing bacteria,

the point during slaughter and dressing at which water is applied has

been deemed significant in retarding or inhibiting attachment.

Notermans et al (1980) concluded that control of Enterobacteriaceae and

salmonellae was more effective when carcasses were spray-cleaned with

water at multiple stages during evisceration than when washing occurred

only after evisceration.

Water pressure can influence the effectiveness of carcass washing

treatments. De Zuniga et al (1991) investigated the effect of increased

water pressure on the penetration of bacteria into tissue using Blue

Lake dye. As the pressure of the water increased, the dye penetrated to

a correspondingly greater depth in the tissue. They recommended an

optimal water pressure for washing beef carcasses between 100 psi to

300 psi. They cautioned that higher pressures may drive the organisms

deeper into the tissues, while pressures less that 100 psi were less

effective at reducing bacterial counts. Kotula (1974) found that water

containing 200 ppm chlorine, sprayed at a pressure of 355 psi and at

temperatures ranging from 55-125 deg. F, effectively removed bacteria

from market beef forequarters. Kotula et al. (1974) concluded that

water pressure was a more important variable than pH or water

temperature for removing bacteria by spray washing. These beef samples,

however, were not freshly slaughtered, and may have required more

intense pressures. Jerico et al. (1995), concluded that washing beef

carcasses with water at 200-400 psi at 38 deg.C (100.4 deg.F) did not

significantly change the level of bacteria on the carcass. They noted

that other investigators (Anderson, 1981; Kotula et al., 1974; Crouse

et al., 1988) did not statistically validate the sample size to adjust

for variation in counts and sample size, and did not collect samples

immediately after washing.

Increasing water pressures has been found to have certain

operational disadvantages. For example, greater pumping pressure is

required, thus requiring more energy and special equipment, less heat

energy can be recovered from the outlet water steam, and the nozzle is

more likely to become blocked if water is recirculated (Graham et al.,

1978).

B. Beef Carcass Trimming vs. Washing Treatment Studies

Only three studies directly compare hand trimming vs. washing as

methods to remove fecal and bacterial contamination from beef

carcasses. Hardin et al. (1995) conducted an FSIS-supported research

project designed to compare traditional hand trimming procedures to

washing of beef carcasses for removal of feces and associated bacteria.

Paired cuts from four carcass regions (inside round, outside round,

brisket, and clod) were removed from hot, split carcasses, then

contaminated with a fecal suspension containing either E. coli 0157:H7

or S. typhimurium (10 \6\ CFU/ml). Inoculated meat cuts

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(400 cm\2\ area) were treated by one of four treatments either

immediately or 20-30 min post-contamination. One paired contaminated

surface region from each carcass side was trimmed of all visible fecal

contamination. The remaining paired carcass surface region was then

washed either with water (35 deg.C/95 deg.F), water wash with 2% lactic

acid (55 deg.C/131 deg.F), or water wash with 2% acetic acid (55 deg.C/

131 deg.F). Samples for microbiological analyses were collected pre-

and post-treatment from within and outside the defined area

contaminated with the fecal suspension.

All treatments significantly reduced levels of pathogens; however,

decontamination was affected by carcass surface region. The inside

round region was the most difficult carcass surface to decontaminate,

regardless of treatment. Washing followed by organic acid treatment

performed better than trimming or washing alone on all carcass region

surfaces except the inside round, where organic acid treatments and

trimming performed equally well. Overall, 2% V/V lactic acid reduced

levels of E. coli 0157:H7 significantly better than 2% V/V acetic acid;

however, differences between the abilities of the acids to reduce

Salmonella were less pronounced. All treatments caused minimal spread

of pathogens outside the initial area of fecal contamination. Recovery

after spreading was reduced by the use of organic acid treatments.

This study is limited in relation to evaluating commercial

conditions due to the experimental design, which deliberately added

inoculated feces to the carcass. A rather large area (400 cm\2\) was

inoculated and deliberate placement on the meat surface allowed the

trimmer to know exactly where fecal contamination occurred. Under

commercial situations, fecal contamination must first be visually

located and the borders of contamination subjectively evaluated. This

subjectiveness may allow the trimmer to inadvertently touch the knife

to areas of fecal contamination that are not obviously visible, thereby

cross-contaminating the freshly trimmed areas as the knife blade is

drawn across. Knife trimming was highly controlled in these

experiments, whereas knife trimming under commercial conditions might

be expected to yield more variable results. Secondly, although this

study was performed in an abattoir, the treatments were performed in an

adjacent laboratory setting rather than on a slaughter line where

deliberate inoculation of carcasses with pathogens is not allowed by

FSIS.

The second direct comparison of trimming vs. washing involved work

performed by scientists from four universities. This study was

conducted in four phases, and is commonly referred to as the National

Livestock and Meat Board study, for the organization that funded the

project.

Phase I trials sought to define the proper parameters for the

washing experiments (Gorman et al., 1995, submitted for publication;

Smith et al., 1995, submitted for publication; Smith, 1995). Results of

Phase I suggested that higher pressures of 20.68 bar (300 psi) and

27.58 bar (400 psi) during spray-washing were more effective (P10 CFU/cm2. The

best combination and sequence of interventions for reducing bacteria

counts on beef brisket samples were: (a) Use 74 deg.C water in the

first wash with water pressure at 20.68 bar, and (b) if colder

(2

and trimming with plain water (2. These data indicated that

trimming reduces microbiological contamination after carcasses are

contaminated with fecal material but a significant amount of

contamination remained on samples after trimming or trimming with spray

washing. It was concluded that washing at 300 psi was as effective as

trimming and washing combinations for reducing bacterial counts on the

tissues. When water was 74 deg.C, reductions were greater than 3.0 log

CFU/cm2, irrespective of the presence or absence of chemical

sanitizer.

Spray-washing with hot water resulted in less variability in

bacterial counts obtained after treatment compared to hand-trimming

and/or spray-washing with water of lower temperatures. The authors

concluded that this greater variability in bacterial counts for hand-

trimming treatments indicated the potential for cross-contamination

during the process.

Phase IIIA consisted of field studies in six commercial plants and

concluded that: (a) Compared to inoculated controls (no trim; no wash),

every combination of washing--with or without trimming and with and

without chemical agents--lowered (P10 when the initial aerobic plate count (APC)

is less than or equal to 104 CFU/cm2. A few investigators have

reported a two or three log reduction (Snijders, 1979; Smulders and

Woolthius, 1983; Netten, 1984). Overall, the available scientific data

indicate that treating carcasses with an organic acid rinse, spray, or

dip can achieve a 90-99.9% (1-3 log10) reduction in the level of

spoilage organisms such as Pseudomonas fluorescens (Dickson and

Anderson, 1992; Prasai et al., 1991; Frederick et al., 1994).

Decontaminating carcasses with lactic or acetic acid can extend the

shelf life of treated product (Smulders and Woolthuis, 1985; Woolthius

and Smulders, 1985). In addition, organic acid sprays and dips have

been shown to decrease the levels of specific pathogens, such as

Salmonella spp., Staphylococcus aureus, C. jejuni, Yersinia

enterocolitica, and L. monocytogenes (Osthold et al., 1984; Bell, et

al., 1986; Smulders, et al., 1986; Anderson, et al., 1987; Siragusa and

Dickson, 1992; and Cutter and Siragusa, 1994). Reductions in the number

of pathogenic bacteria on carcasses reduce the risk of food-borne

disease.

Each organic acid differs in its ability to reduce the bacterial

population on tissue surfaces. The concentration of the organic acid

affects not only bacterial survival, but also the color and odor of the

meat, especially if the concentration is 2% or greater. Bleaching and

discoloration of tissue have been reported, and may occur at 1%

concentrations for lactic and acetic acid (Smulders and Woolthuis,

1985, and Hamby et al., 1987). Balancing antimicrobial activity with

organoleptic impact, the practical concentration for use of lactic or

acetic acids appears to be 0.5 to 2.5%.

Prasai et al. (1991) examined the effect of lactic acid (1.5%,

55 deg.C) applied to beef carcasses at various locations in processing

and found that the greatest reduction in APCs occurred on carcasses

treated immediately after hide removal and again after evisceration.

These reductions, however, were not significantly better than spraying

only after evisceration. After 72 hours of storage (1 deg.C), the

number of bacteria per cm2 on treated carcasses was lower than on

comparable control carcasses. Decontamination with acids is more

effective when employed as soon after slaughter as feasible (Acuff et

al., 1987) and at elevated temperatures (53-55 deg.C).

Treating beef carcasses with acids does not completely inactivate

all pathogens, particularly E. coli 0157:H7, which is relatively acid

tolerant. Cutter and Siragusa (1992) reported that there are

differences among E. coli 0157:H7 isolates in relation to their acid

tolerances. Salmonella spp., L. monocytogenes, and Pseudomonas

fluorescens are more sensitive to acids than E. coli 0157:H7 (Dickson,

1991; Greer and Dilts, 1992; Cutter and Siragusa, 1994; Bell et al.,

1986); while E. coli biotype 1, particularly E. coli 01257:H7, appears

to be among the more resistant enteric bacteria to the effects of

organic acids (Woolthuis et al., 1984; Woolthuis and Smulders, 1985;

Van Der Marel et al., 1988; Bell et al., 1986; Anderson and Marshall,

1990, 1989; Acuff et al., 1994).

The extent of reduction of E. coli 0157:H7 achieved has varied

among studies. For example, Dickson (1991) found that the reduction of

E. coli 0157:H7 was similar to that observed for Salmonella and L.

monocytogenes, with up to a 99.9% reduction in the levels of all three

bacteria from inoculated tissues. A number of other studies have

reported reductions in E. coli and in Enterobacteriaceae (which belongs

to the same family as E. coli) of 46 to 99.9% on tissues treated with

1.2% to 2% acid (Bell et al., 1986; Anderson and Marshall, 1990, 1989;

Cutter and Siragusa, 1994; Greer and Dilts, 1992; Acuff et al., 1994).

Anderson and Marshall (1990) found that although lactic acid exerted a

significant antimicrobial effect on some Enterobacteriaceae, it did not

appreciably affect E. coli or S. typhimurium on beef issue samples.

Conversely, Brackett et al. (1993) reported that up to 1.5% acid

treatments did not appreciably reduce E. coli 0157:H7, whether at 20C

or 55C, and was ``of little value in disinfecting beef of EC 0157.''

Dickson (1991) concluded that an acetic acid carcass sanitizer could be

used as an effective method to control bacterial pathogens. Cutter and

Siragusa (1992) reported that the reduction of E. coli 0157:H7 on meat

by acid treatment is dependent on acid concentration (5% giving the

greatest reduction) and tissue type (greater reduction on fat tissue

than lean). They found lactic acid to be more effective than acetic or

citric acid against E. coli. This has been reported by Hardin et al.,

1995, as well. Cutter and Siragusa (1992) suggested that the two

primary determinants of effectiveness are the pH achieved at the

surface of the carcass and the corresponding period of exposure.

A number of other studies have reported reductions in E. coli or

Enterobacteriaceae ranging from 46 to 99.9% on tissues treated with

1.2% to 2% acid (Bell et al. 1986; Anderson and Marshall, 1990, 1989;

Cutter and Siragusa, 1994; Greer and Dilts, 1992; Hardin et al., 1995).

Anderson and Marshall (1990) found that concentration and temperature

of lactic acid solutions had significant but independent effects on

reduction in numbers of inoculated microorganisms (aerobes,

Enterobacteriaceae, and E. coli) on the surface of lean beef muscle. E.

coli cells, however, were

[[Page 49559]]

comparatively resistant to the effects of temperature and concentration

of lactic acid. Further, Brackett et al. (1993) reported that up to

1.5% acid treatments did not appreciably reduce E. coli 0157:H7,

whether at 20 deg. or 55 deg.C and ``was of little value in

disinfecting beef of EC O157.'' Brackett (1994) also concluded that E.

coli (Biotype I) and E. coli 0157:H7 are quite resistant to the effects

of organic acids, particularly lactic acid. Hardin et al. (1995)

observed that E. coli 0157:H7 was more resistant than S. typhimurium to

the effects of both 2% lactic and 2% acetic acid applied to beef

carcass surface regions. Reductions in levels of E. coli 0157:H7 were

0.6-1.5 log10 CFU/cm2 greater with lactic acid than acetic

acid, depending on the carcass surface tested. Both lactic and acetic

acid, however, were equally effective in reducing levels of S.

typhimurium.

Both acid concentration and temperature have been studied for their

effects on reducing bacterial numbers on beef tissue. Anderson and

Marshall (1989) observed that both concentration and temperature

produced significant, but independent, reductions in numbers of E. coli

and S. typhimurium on beef semitendinosus muscle dipped in an acetic

acid solution. Acid concentration (1, 2, 3%) was found to be

insignificant at the higher temperature (70 deg.C), but caused

significant reduction in numbers of microorganisms at lower

temperatures (22, 40, and 55 deg.C). Anderson and Marshall (1989)

reported that the most effective treatment was dipping pieces of lean

meat in 3% acetic acid at 70 deg.C. They suggested that some direct

effects from heat may have contributed to the increased reduction of

bacterial numbers in samples treated at this higher temperature. The

numbers of surviving organisms were reduced as the temperature of the

acid was increased from 25 to 70 deg.C, with acid concentration being

less significant at higher temperatures. These researchers later

reported similar results for treatments using 3% lactic acid at

70 deg.C (Anderson and Marshall, 1990). Anderson et al. (1987) observed

a greater reduction in levels of indigenous E. coli, Enterobacteriaceae

and APC with hot (52 deg.C) acetic acid when compared to cool

(14.4 deg.C) acetic acid.

In a more recent study, Anderson et al. (1992) reported an

increased removal of bacteria as either the concentration or

temperature of the acid solution was increased, with the acids

performing differently at different temperatures. Lactic acid was

reported to be significantly more effective than acetic acid for all

bacterial types (aerobes, Enterobacteriaceae, S. typhimurium, E. coli)

at both 20 and 45 deg.C, and more effective on S. typhimurium at

70 deg.C. Cutter and Siragusa (1994) reported that of three

concentrations evaluated (1, 3, and 5%), 5% acid (acetic, lactic, or

citric) resulted in the greatest reduction in numbers of both E. coli

0157:H7 and P. fluorescens from beef carcass tissue.

Evaluation of the overall effectiveness of organic acids is

confounded by the fact that the various studies have employed different

acid types, applied at different concentrations and temperatures to

varying types of meat tissue surfaces. Each of these factors has an

effect on the removal of bacteria from carcasses. Several studies have

evaluated the effect of tissue type (fat and lean) on the effectiveness

of organic acids to reduce the number of bacterial cells from beef

tissue surfaces. Cutter and Siragusa (1994) reported that the magnitude

of bacterial reductions from beef surfaces treated with organic acids

was consistently greater when spray treatments were applied to bacteria

attached to adipose tissue. Log reductions for E. coli 0157:H7 and P.

fluorescens were 1 and 2 log10 greater on adipose vs. lean beef

carcass tissue. These findings agree with Dickson and Anderson (1991),

who reported significant reductions in S. california from use of

distilled water and 2% acetic acid with beef fat tissue, whereas no

significant differences were observed between treated and untreated

lean tissues. Dickson (1991, 1992) reported similar findings for S.

typhimurium, L. monocytogenes, and E. coli 0157:H7 attached to fat

surfaces of beef trim. Acid treatment resulted in an immediate

sublethal injury of approximately 65% of S. typhimurium (Dickson, 1992)

remaining on lean and fat tissue. A residual effect from the acid was

observed with the fat tissue, resulting in an additional 1 log \10\

decrease over four hours. The author suggested that the differences

observed in the effects of acid for lean and fat tissue were due to the

increased water content of lean tissue and the presence of water-

soluble components that may neutralize the acid and its effect on the

bacterial cell. In a comparison of methods for the removal of S.

typhimurium and E. coli 0157:H7 from various beef carcass surfaces,

Hardin et al. (1995) found a significant difference in the type of

surface evaluated. The researchers observed that the inside round was

the most difficult carcass surface to decontaminate and attributed this

to a substantial amount of exposed lean on the meat surface, as well as

a pronounced collar of fat at the edge of the lean.

Organic acids have been reported to be more effective in reducing

bacterial levels when applied during, or shortly after, slaughter and

dressing. Acuff et al. (1987) and Dixon et al. (1987) reported no

significant difference in reduction of aerobic populations from beef

steaks and subprimals treated post-fabrication with various organic

acids and their controls. They suggested that the application of acid

decontamination would be most effective as soon as possible after

slaughter, before bacteria have had a chance to attach firmly to meat

surfaces. This was supported by Brackett et al. (1994), who recently

reported that hot acid sprays were ineffective in reducing levels of E.

coli 0157:H7 inoculated onto the surface of sirloin tips purchased from

local butchers. Snijders et al. (1985) reported an increase in the

bactericidal effect of lactic acid sprayed on hot carcasses (45 minutes

postmortem) when compared to spraying on chilled carcasses. They

suggested that on hot carcass surfaces, increased reductions may be due

to higher levels of bacteria present in the water film and not yet

attached to the carcass surface. Van Netten et al. (1994) described an

in vitro model to evaluate the inactivation kinetics of bacteria from

meat surfaces treated with lactic acid. A rapid reduction in bacterial

numbers due to the replacement of the fluid (water film) on a warm meat

surface by a film containing lactic acid was referred to as ``immediate

lethality.'' They proposed that organisms on chilled meat are less

accessible to lactic acid and are better protected by meat buffering

effects than those in the fluid film of hot meat surfaces.

D. Chlorine and Chlorine Compounds

Chlorine, chlorine dioxide, sodium hypochlorite, and hypochlorous

acid all have been sprayed onto beef carcasses in an effort to reduce

microbial populations.

Chlorine and chlorine dioxide were compared for chickens by Lillard

(1979) to determine their relative bactericidal effect. Chlorine

dioxide was found to be more potent than chlorine and required only

one-seventh as much to produce the same bactericidal effect. Further,

chlorine dioxide maintained its effectiveness when both pH and the

level of organic matter increased. Chlorine is less effective when the

pH or organic load is increased. Kotula et al. (1974) treated beef

forequarters with chlorinated water (200 ppm) and found initial

reductions (45 min post-treatment) in APCs for duplicate testing days

of 1.5 and 2.3 log10 CFU/cm2, respectively. Temperature (12.8

vs 51.7 deg.C) and pH (4 to 7) were found to

[[Page 49560]]

significantly affect efficacy, with the greatest reductions observed at

a temperature of 51.7 deg. and pH values of 6 and 7.

Anderson et al., (1979) compared the effectiveness of several

treatments to reduce APCs on previously frozen beef plate stripes. Meat

was washed and sanitized with cold water (15.6 deg.C [60 deg.F]), hot

water (76-80 deg.C [168-176 deg.F]) (14kg/cm2), sodium

hypochlorite (200-250g/ml), or acetic acid (3%)--all at 14kg/

cm2; and at 17 kg/cm2 steam at 95 deg.C (194 deg.F). They

found that the sodium hypochlorite and cold water treatments reduced

counts by about one log. Steam reduced the count by only 0.06 log. Hot

water reduced counts by 2.0 log and acetic acid reduced counts by 1.5

log. Over time, samples treated with hypochlorite had rates of

bacterial re-growth that exceeded those of the untreated controls.

Steam and cold water treated samples exceeded APCs on controls after

five days, presumably due to greater surface moisture from the

treatment. Growth rates associated with the hot water samples were

similar to the untreated controls, but, because of the initial 2.0 log

reduction in microbial levels, it took nearly five additional days

before counts reached 108/cm2. Acetic acid, applied to

samples after a cold water wash, provided a 14-16 day delay before

counts returned to initial levels, and it took a full 23-24 days before

the bacteria reached 108/cm2.

V. Other Technologies

Several other approaches or technologies have been suggested as

additional alternative means for decontaminating beef carcasses, such

as rinsing with trisodium phosphate (TSP), steam pasteurization of

carcasses, steam vacuuming, and chemical dehairing. These approaches

have not been as extensively investigated and reported in the

scientific literature to date, relative to their use with beef

carcasses. A brief discussion of each method follows.

A. Trisodium Phosphate

Trisodium phosphate (TSP) has been shown to reduce Salmonella on

processed poultry carcasses. In a 1991 patent, Bender and Brotsky

presented the claim that trisodium phosphate (Na3PO4) could

successfully reduce Salmonella on processed poultry carcasses. Since

then, industry, university, and USDA Agricultural Research Service

researchers have conducted studies that demonstrate reductions in

Salmonella levels on poultry carcasses ranging from 90 to greater than

99.9% (1.2 to 8.3 log10). Dickson et al. (1994) studied the effect

of TSP on beef tissue dipped in TSP after inoculation with both Gram

positive (L. monocytogenes) and Gram negative (S. typhimurium and E.

coli 0157:H7) pathogens. They reported reductions of 1 to 1.5

log10 for the Gram-negative pathogens, and a maximum reduction of

less than one log10 for L. monocytogenes on lean tissue. Reduction

of L. monocytogenes was greater on fat tissue: 1.2 to 1.5 log10. A

reduction of 2 to 2.5 log10 for S. typhimurium and E. coli 0157:H7

on fat tissue was reported.

In-plant testing of TSP on beef carcasses (Rhone-Poulenc) showed a

greater than 1.5 log10 reduction of E. coli (biotype I). Further,

they found that incidence rates for E. coli fell from 51.3% on

untreated carcasses to 1.3% on TSP-treated carcasses. The level of

Enterobacteriaceae was reduced by one log10, and the incidence

rates fell from 75% on untreated carcasses to 8.8% on treated

carcasses. Salmonella was not detected on any carcasses.

B. Steam Pasteurization

A patent-pending process developed by Frigoscandia for steam

pasteurization of meat and poultry has been tested at Kansas State

University and has received approval by FSIS for in-plant evaluation;

the process is applied at the end of beef dressing operations on

inspected and passed carcasses. A request by Frigoscandia to evaluate

and test the process as an antimicrobial reduction intervention is

being considered by FSIS.

Tests of a prototype unit at Kansas State University showed that

the process consistently reduces pathogenic bacteria, including E. coli

0157:H7, by 99.9% (Frigoscandia, 1995). The process uses pressurized

steam applied uniformly to the entire carcass surface, producing

surface meat temperatures of 77-93 deg.C (170-200 deg.F) and a uniform

bacterial reduction on the entire carcass. Since the steam reaches all

exposed surfaces, the reduction is more uniform and operator-

independent. The process is reported to not affect the color of the

carcass, and to use less energy than is required for a comparable hot

water system. Furthermore, the use of a 2% lactic acid cooling spray

immediately after steam application appeared to act synergistically to

inactivate surface bacteria. It should be noted that the intended use

of the steam pasteurization is not the direct physical removal of

visible contamination, but the technology has the potential to be

integrated into pathogen control systems to enhance their

effectiveness.

C. Steam Vacuuming

Alternative methods for removing beef carcass contamination such as

air jets and vacuum systems (without steam) have been shown to be

effective in removing visible as well as microbiological contamination

(Monfort, 1994). Steam vacuuming is a refinement of this approach,

combining physical removal with microbial inactivation. Steam vacuuming

is a process in which steam and hot water are applied through nozzles

to the carcass surface after the hide is removed. This appears to be

particularly useful for opening cuts, which are made in the hide to

facilitate hide removal. These carcass surfaces tend to be contaminated

more frequently than other areas of the carcass. Steam vacuuming treats

these surface areas with hot water (above 160 deg.F) and steam while

vacuuming the removed contamination and any excess water from the

surface. The process of steaming the opening patterns encountered some

difficulty in early trials when the steam nozzle was held 6 to 12

inches from the surface. There was a rapid drop in temperature, and as

a result no significant differences in bacterial levels were noted from

treated areas. These problems were corrected by adjusting the equipment

and placing the head of the vacuum directly on the surface. Testing at

Kansas State University has shown the effectiveness (>99.9% reduction)

of steam vacuuming in decontaminating prerigor meat surfaces that have

been inoculated (approximately 105 CFU/cm2) with the

pathogens L. monocytogenes, E. coli 0157:H7, and S. typhimurium.

Scientists at the U.S. Meat Research Center of USDA's Agricultural

Research Service at Clay Center, Nebraska have reported a 3.0 to 3.5

log (>99.9%) reduction in bacteria on steam vacuum-treated meat.

Preliminary results from an ongoing industry study (ten plants reported

to date) comparing steam vacuuming and knife trimming to remove carcass

contamination indicate that carcasses that have been steam vacuumed

have approximately 90% (0.94 log) less bacteria than trimmed carcasses

in the areas tested. Several inplant trials comparing steam vacuuming

versus traditional trimming are currently underway.

D. Chemical Dehairing

The effects of post-exsanguination (post-bleeding) dehairing on the

microbial load and visual cleanliness of beef carcasses has been

studied by Schnell et al., 1995. Ten grain-fed steers/heifers were

slaughtered and

[[Page 49561]]

dressed without dehairing. The carcasses of these animals were

evaluated for bacterial contamination and visual defects (hair and

specks) and for weight of trimmings made to meet ``zero tolerance.''

Overall, no difference was reported in aerobic plate counts, total

coliform counts, and E. coli counts between samples from dehaired

cattle and those from conventionally-slaughtered cattle. The lack of

difference in bacterial counts was thought to be due to contamination

in the facility from aerosols, and from people and equipment

contaminated by conventionally-slaughtered cattle. An interaction was

noted, however, between treatment and carcass sampling location. E.

coli counts were lower in samples taken from rounds of dehaired

carcasses than in samples from rounds of conventionally-slaughtered

carcasses. The converse was found for samples from briskets, where

higher counts were thought to be due to the additional handling of

dehaired carcasses, i.e., the necessity of cutting the hide to assist

in removal of hides that had become soapy and slippery during the

dehairing process.

The investigators stated the opinion that the microbiological

status of carcasses from dehaired animals should improve in facilities

designed to produce only dehaired carcasses. Dehaired carcasses had

fewer visible specks and fewer total carcass defects before trimming

(but not after trimming) than did conventionally-skinned carcasses. The

average amount of trimmings removed from conventional carcasses to meet

the ``zero tolerance'' specification was almost double (2.7 versus 1.4

kg) that from dehaired carcasses.

Additional tests, conducted in support of an industry petition

(Monfort, 1995), compared the reduction of bacteria from hide to

dehaired hide immediately after the dehairing process. These tests

found a 99% reduction in total plate counts.

VI. The Conference

FSIS is committed to ensuring that the most effective means

available are used to achieve the zero tolerance standard for fecal,

ingesta, and milk contamination of beef carcasses. The Agency's goals

are to protect consumers from harmful contamination and thus reduce

their risk of contracting foodborne illnesses. Given the importance of

these goals, determining the most effective means of implementing the

zero tolerance performance standard is one of FSIS's highest

priorities. FSIS will act on the basis of sound scientific evidence,

discussed in an open public process, to improve the safety of beef

products through effective removal of fecal and associated microbial

contamination.

Accordingly, FSIS is hosting a conference to review the scientific

and technical data and associated public policy issues involved in

achieving the zero tolerance standard and improving beef carcass

microbial safety. The conference will consist of two sessions on

consecutive days. At the first session, participants will discuss

available scientific and technical data comparing the efficacy of

various methods for decontaminating beef carcass surfaces, focusing on

the research summarized above. Participants are invited to make 15-

minute presentations during this first session and are requested to

submit to FSIS, in advance, brief statements describing the general

topics of their presentations (see ADDRESSES above). A panel of

government scientists and managers will participate in this session and

facilitate the discussion; the panel will be moderated by Ms. Patricia

F. Stolfa, Acting Deputy Administrator, Science and Technology, FSIS.

An opportunity will be provided for open discussion of scientific

issues among all participants. Possible scientific and technical

questions for discussion are:

1. Do the studies offered to support the various decontamination

alternatives conform to appropriate scientific standards?

2. Are key results from individual studies reproducible and have

they been replicated in other experiments?

3. How effective is any specific treatment against microbial

pathogens, and against E. coli 0157:H7 in particular?

4. Is a specific treatment bactericidal or bacteristatic?

5. Has a treatment been studied under plant conditions?

6. What are the most effective locations for treatment on the

carcass and on the slaughter line?

7. If water is used, in what amounts? Can water be conserved or

reused?

8. Is there any threat to workers or the environment from residual

treatment fluids, chemical waste, or biological hazards?

9. Does a proposed treatment create an insanitary condition?

10. Does a proposed treatment spread contamination on a carcass or

spread contamination from carcass to carcass?

11. Can - and should - a treatment be combined with other

treatments? What would be the optimum combination?

12. Does a proposed treatment interfere with current inspection

procedures?

13. When all the relevant studies are considered, does a

discernible trend emerge supporting a policy choice?

During the second session, participants will discuss the public

policy issues surrounding beef carcass decontamination. This session

will be moderated by Thomas J. Billy, Associate Administrator, FSIS,

and Dr. Craig Reed, Deputy Administrator, Inspection Operations, FSIS.

Possible policy questions for discussion are:

1. What criteria should be used to decide that an alternative

approach meets the zero tolerance performance standard for visible

fecal contamination and associated microbial contaminants?

2. What amount and quality of scientific data should be required in

order to change current policy?

3. Are alternative approaches equally feasible for all

establishments that may want to use them?

4. Should FSIS prescribe exactly how fecal contamination may be

removed or should there be an organoleptic and microbial performance

standard that companies can achieve as they see fit?

5. What techniques should the FSIS inspection force use to verify

that an alternative approach is functioning effectively?

6. Should preventive measures be made part of this policy decision?

7. What approaches to achieving the zero tolerance performance

standard are consistent with a HACCP approach to process control?

Conference Registration

FSIS is requesting that persons planning to attend the conference

preregister. If you plan to attend, please contact Ms. Mary Gioglio at

(202) 501-7138 to register. Registration will also be available on the

days of the conference on a space-available basis.

Also, if you require a sign language interpreter or other special

accommodations, please contact Mary Gioglio at the number listed above.

Done at Washington, DC on September 20, 1995.

Michael R. Taylor,

Acting Under Secretary for Food Safety.

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