[Federal Register Volume 64, Number 88 (Friday, May 7, 1999)]
[Notices]
[Pages 24661-24663]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-11319]


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DEPARTMENT OF HEALTH AND HUMAN SERVICES

Food and Drug Administration
[Docket No. 99N-1076]


Risk Assessment of the Public Health Impact of Foodborne Listeria 
Monocytogenes; Request for Comments and for Scientific Data and 
Information

AGENCY: Food and Drug Administration, HHS.

ACTION: Notice; request for comments and for scientific data and 
information.

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SUMMARY: The Food and Drug Administration (FDA), in consultation with 
the U.S. Department of Agriculture's Food Safety and Inspection Service 
(USDA/FSIS), is announcing plans to conduct a risk assessment (RA) to 
determine the prevalence and extent of exposure of consumers to 
foodborne Listeria monocytogenes and to assess the resulting public 
health impact of such exposure. The agencies request comments on 
certain aspects of their approach to the RA and request that scientific 
data and information relevant to the conduct of the RA be submitted.

DATES: Written comments and scientific data and information by July 6, 
1999.

ADDRESSES: Submit written comments and scientific data and information 
to the Dockets Management Branch (HFA-305), Food and Drug 
Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852.

FOR FURTHER INFORMATION CONTACT: Richard C. Whiting, Center for Food 
Safety and Applied Nutrition (HFS-300), Food and Drug Administration, 
rm. 3822, 200 C St. SW., Washington, DC 20204, 202-260-0511, FAX 202-
260-9653, or e-mail ``[email protected]''.

 SUPPLEMENTARY INFORMATION:

I. Background

    L. monocytogenes is a bacterium that occurs widely in both the 
agricultural (soil, plants, and water) and food processing environment. 
The bacterium is resistant to various environmental conditions such as 
high salt or acidity (Ref. 1).  L. monocytogenes grows at low oxygen 
conditions and refrigeration temperatures, and survives for long 
periods of time in the environment, on foods, in processing plants, and 
in household refrigerators. Although frequently present in raw foods of 
both plant and animal origin, it also can be present in cooked foods 
due to post-processing contamination.  L. monocytogenes has been 
isolated in such foods as: Raw and pasteurized fluid milk, cheeses 
(particularly soft-ripened varieties), ice cream, raw vegetables, 
fermented raw meat sausages, raw and cooked poultry, raw meats (all 
types), and raw and smoked fish (Refs. 1, 2, and 3). Even when L. 
monocytogenes is initially present at a low level in a contaminated 
food, the organism can multiply during storage, including storage at 
refrigeration temperatures. A survey of a wide variety of foods from 
the refrigerators of listeriosis patients in the United States found 11 
percent of the samples contained L. monocytogenes (Ref. 4).
     It is well established that ingestion of L. monocytogenes can 
cause serious human illness, listeriosis (Refs. 1, 2, 5, 6, and 7). In 
1997, the Centers for Disease Control and Prevention (CDC) Foodborne 
Diseases Active Surveillance Network (FoodNet) showed that of all 
foodborne illnesses, the rate of hospitalization was highest for 
persons infected with L. monocytogenes (88 percent). Similarly, of all 
of the foodborne pathogens tracked by CDC, L. monocytogenes had the 
highest case fatality rate in that 20 percent of persons infected died. 
CDC also found that the incidence of listeriosis is 0.5 per 100,000 
population, compared to a combined rate of 51.2 per 100,000 for all 9 
of the foodborne illnesses surveyed (Ref. 8). Thus, although serious, 
listeriosis is a relatively rare foodborne illness. Most cases of 
listeriosis occur in pregnant women or individuals with a predisposing 
disease (such as alcoholism, diabetes, or cirrhosis of the liver) or an 
impaired immune system resulting from either a disease (such as AIDS) 
or immunosuppressive treatment for a malignancy or an organ transplant. 
(Refs. 1 and 6).
    Listeriosis has a long incubation time (up to 5 weeks) and a range 
of symptoms. Infection of a pregnant woman may result in flu-like 
symptoms with fever, muscular pain, or headache, or the listeriosis 
infection may be asymptomatic. Importantly, however, when a pregnant 
woman contracts listeriosis, the fetus or newborn infant is likely to 
suffer severe consequences from the maternal infection, including: 
Spontaneous abortion, fetal death, stillbirth, neonatal septicemia, or 
meningitis. In nonpregnant adults, septicemia and meningitis are the 
most common result of a listeriosis infection, although organ 
infections and mild gastroenteritis can also occur.
     Although the consequences of listeriosis may be severe, an 
estimated 2 to 6 percent of the healthy population harbors L. 
monocytogenes in their intestinal tract without signs of illness (Refs. 
1 and 6). Because the documented prevalence of L. monocytogenes in 
people and in commonly eaten foods is much higher than the documented 
incidence of listeriosis, some experts believe that the ingestion of 
low levels of L. monocytogenes may not result in illness and thus, may 
not constitute a general public health hazard (Refs. 9 and 10).
    Since 1990, CDC has documented a decrease in the incidence of 
listeriosis. Although not certain, this decrease may be attributed to 
government and industry programs directed at improved sanitation and 
process control. Listeriosis is typically characterized by sporadic 
cases. However, a recent multi-State listeriosis outbreak associated 
with the consumption of processed meats, with at least 73 illnesses and 
16 deaths, has reaffirmed concerns that more preventative efforts are 
needed.
    Historically, FDA has had a policy of ``zero tolerance'' for L. 
monocytogenes based on the absence of the microorganism in a 25-gram 
sample of a given production lot. In other words, FDA's position has 
been that the detection of any L. monocytogene in a 25-gram sample 
renders the food adulterated within the meaning of the Federal Food, 
Drug, and Cosmetic Act (21 U.S.C. 342(a)(1)). As recently as 1995, FDA 
affirmed this policy, as reflected in the decision in United States v. 
Union Cheese Co., 902 F. Supp. 778, 784, 786 (N.D. Ohio 1995). In that 
litigation, FDA's expert witness testified that the L. monocytogenes 
bacterium grows at refrigerator temperatures and that the level of L. 
monocytogenes required to cause illness is unknown (902 F. Supp at 
784). FSIS (which regulates meat and poultry) likewise has historically 
had a zero tolerance policy for L. monocytogenes.
    Other countries, including certain major trading partners of the 
United States, take a slightly different approach to L. monocytogenes 
contamination. Relying upon their interpretation of the existing 
scientific data, countries such as Canada and Denmark have a ``non-zero 
tolerance'' for L. monocytogenes for some classes of foods (Refs. 10 
and 11).

[[Page 24662]]

 For example, in Canada, ready-to-eat foods that have not been 
associated with an outbreak and do not allow any growth of L. 
monocytogenes during a 10-day period of refrigerated storage may 
contain up to 100 L. monocytogenes organisms per gram without being 
considered unlawful (Ref. 12). Denmark has six classes of foods that 
have to meet various criteria for L. monocytogenes. In raw, ready to 
eat foods, for example, 2 of 5 samples can contain between 10 and 100 
organisms per gram, and no sample can exceed 100 organisms per gram. 
Although the course taken by other countries concerning L. 
monocytogenes contamination is not determinative of the U.S. approach, 
the policies of certain major trading partners provides further context 
to any reexamination of current U.S. policy.
    Quantitative RA has recently been identified as a useful tool for 
evaluating the public health impact of microbial contamination. USDA/
FSIS and FDA recently completed a quantitative RA of Salmonella 
Enteritidis in shell eggs and egg products (Ref. 13). This RA is being 
used to review and evaluate Federal regulatory approaches to ensuring 
the safety of these products.
    As noted, although the incidence of listeriosis is relatively low, 
the consequences of such infection are quite serious. A quantitative RA 
of the prevalence and extent of exposure of L. monocytogenes will 
provide a structured approach to synthesize and evaluate the available 
data and information. To the extent that U.S. policy regarding L. 
monocytogenes contamination requires reexamination, such a RA can serve 
as a foundation for such reconsideration.

II. Objectives of the Risk Assessment

    As noted previously, FDA and USDA/FSIS are jointly planning to 
conduct an assessment of the risk posed by L. monocytogenes to American 
consumers. A RA is a systematic and comprehensive collection of 
information and analysis of such information that promotes an 
understanding of the interactions of various factors in a complex 
situation and provides a basis for making decisions. The goal of this 
RA is to provide FDA and FSIS with the information needed to review 
current programs relating to the regulation of L. monocytogenes 
contamination in foods to ensure that such programs provide maximum 
public health protection.

III. Risk Assessment Plan

    The RA will seek and analyze three types of information: 
Information concerning the epidemiology of foodborne listeriosis, 
information concerning the level of L. monocytogenes contamination of 
foods and consumption levels of such foods (i.e., an exposure 
assessment), and information regarding the human health consequences of 
such exposure (i.e., a dose-response analysis).
    1. The RA will analyze epidemiological evidence concerning the 
foods implicated both in documented outbreaks and in sporadic cases of 
listeriosis, the numbers of L. monocytogenes consumed, the populations 
which became ill, and the severity of their illnesses.
    2. The exposure assessment component of the RA will determine the 
frequency of occurrence of L. monocytogenes in different classes of 
foods, particularly the ready-to-eat foods that are intended for 
consumption without additional heating. Ready-to-eat foods are 
represented by numerous types of dairy, seafood, meat, and plant 
products. The RA also will collect and analyze information on the 
number of viable organisms associated with these foods at the time of 
consumption. When data are collected at processing stages prior to 
consumption, the RA will utilize models for growth, survival, or 
thermal inactivation to estimate actual exposure of the consumer to L. 
monocytogenes. The RA also will utilize food consumption databases to 
assess the amount of these foods that are consumed. The RA will use the 
information about the frequency of occurrence and numbers of L. 
monocytogenes and food consumption to estimate the number of L. 
monocytogenes cells consumed.
    3. The RA will include an evaluation of the dose-response 
relationship, which will describe the health effects from consuming 
specific numbers of L. monocytogenes organisms. The information that 
will form the basis of the dose-response relationship element of the RA 
may come from epidemiological, animal, or in vitro studies. FDA and 
FSIS recognize that the frequency and severity of illness may be 
affected by the food matrix, characteristics of specific strains of the 
organism, and variability in human susceptibility.
    The RA will examine a number of issues, including: What foods 
contribute most to the consumption of L. monocytogenes, what are the 
numbers of organisms when a food is contaminated, how frequently are 
foods heavily contaminated, are some strains of L. monocytogenes more 
virulent that others, what is the extent of organism growth during 
storage (including storage at refrigeration temperatures), and what is 
the likelihood of illness to various subpopulations from consuming 
different numbers of L. monocytogenes. All assumptions and 
uncertainties in the RA will be identified and documented. The RA 
process will also include an evaluation of the adequacy of current 
scientific knowledge, data, and information. This will suggest where 
future research could be directed to reduce any uncertainty in the risk 
estimate that prevents a clear understanding of the causes and impact 
of listeriosis.

IV. Data and Information Requested

    FDA and FSIS request comments on the risk assessment approach 
outlined previously and the submission of any information relevant to 
this RA. The agencies specifically request scientifically valid data on 
the quantitative levels of L. monocytogenes in foods and data relating 
to rate of consumption of foods likely to contain high levels of L. 
monocytogenes.
    FDA believes that the credibility and validity of the RA require 
that the process for the conduct of the RA be transparent, and thus, 
all the data and information evaluated in the context of the RA and 
utilized in the RA must be publically available. Accordingly, any data 
or information submitted in response to this notice should be in a form 
that permits public disclosure. Submitters of data and information 
should not mark any information as ``Confidential'' and should fully 
expect that any data or information submitted will be made available to 
the public. Questions regarding the public availability of data and 
information submitted in response to this notice should be directed to 
the contact person above.
    As noted, the purpose of this request for data is to gather 
relevant information to facilitate a valid RA of L. monocytogenes with 
the larger goal of providing a sound scientific basis for the agencies' 
policies regarding the regulation of L. monocytogenes contamination in 
food. Although FDA would seek to remove from the market any existing 
food product known to be adulterated, FDA does not intend to utilize 
the submitted data and information to support future enforcement 
activity against the manufacturers submitting the data. Accordingly, it 
is acceptable that data submitted in response to this notice be 
``blinded'' in the sense that the data need not identify the particular 
manufacturer or processor that was the source of the samples underlying 
the results.

[[Page 24663]]

    The RA team plans to present a summary of available literature to 
the National Advisory Committee on Microbiological Criteria for Foods 
at a meeting scheduled for May 26 through 28, 1999, in Chicago, IL. A 
copy of the literature summary will be available prior to that meeting 
on the Internet at ``http://vm.cfsan.fda.gov''. Comments and data 
submitted in response to this notice or at that meeting will be 
incorporated into the RA process, and the completed RA will be 
publically presented in September 1999.
    Two copies of comments and scientific data and information are to 
be submitted, except that individuals may submit one copy. Comments and 
scientific data and information should be addressed to the Dockets 
Management Branch (address above) and identified with the docket number 
found in brackets in the heading of this document. Received materials 
may be seen in the Dockets Management Branch between 9 a.m. and 4 p.m., 
Monday through Friday.

V. References

    The following references have been placed on display in the Dockets 
Management Branch (address above) and may be seen by interested persons 
between 9 a.m. and 4 p.m., Monday through Friday.
    1. Ryser, E. T. and E. H. Marth, Listeria, listeriosis, and food 
safety, Dekker, NY, 1991.
    2. Farber, J. M. and P. I. Peterkin, ``Listeria monocytogenes, a 
Food-borne Pathogen,'' Microbiology Review, 55:476-511, 1991.
    3. FDA, Bad Bug Book (Foodborne Pathogenic Microorganisms and 
Natural Toxins), 1999, Internet address: ``http://vm.cfsan.fda.gov/
mow/intro.html''.
    4. Pinner, R. W., A. Schuchat, B. Swaminathan, P. S. Hayes, K. 
A. Deaver, R. E. Weaver, B. D. Plikaytis, M. Reeves, C. V. Broome, 
and J. D. Wenger, ``Role of Foods in Sporadic Listeriosis. 2. 
Microbiologic and Epidemiologic Investigation,'' Journal of the 
American Medical Association, 267:2046-2050, 1992.
    5. CAST, ``Foodborne Pathogens,'' Council for Agricultural 
Science and Technology, Task Force Report 122, Ames, IA, 1994.
    6. Rocourt, J. and P. Cossart, ``Listeria monocytogenes,'' In 
Food Microbiology, Fundamentals and Frontiers, edited by M. P. 
Doyle, L. R. Beuchat, and T. J. Montville, ASM Press, Washington, 
DC, 1997.
    7. Miller, A. L., J. L. Smith, and G. A. Somkuti, ``Foodborne 
Listeriosis,'' Soc. Indust. Microbiol., Elsevier, NY, 1990.
    8. CDC, Morbidity and Mortality Weekly Report, ``Incidence and 
Foodborne Illnesses-Foodnet,'' 47(37);782, 1997.
    9. Farber, J. M., W. H. Ross, and J. Harwig, `` Health Risk 
Assessment of Listeria monocytogenes in Canada,'' International 
Journal of Food Microbiology, 30:145-156, 1996.
    10. ICMSF, ``Choice of Sampling Plan and Criteria for Listeria 
monocytogenes,'' International Journal of Food Microbiology, 22:83-
96, 1994.
    11. IFST, Microbiological Criteria for Retail Foods, 
Professional Food Microbiology Group, Inst. Food Science and 
Technology, Lett. Appl. Microbiol, 20:331-332, 1995.
    12. Health Canada, Compliance Guide/Policy on Listeria 
monocytogenes in Ready-to-Eat Foods, 1994.
    13. FSIS, Salmonella Enteritidis Risk Assessment, Shell Eggs and 
Egg Products, USDA, FSIS, Washington, DC, 1998.

    Dated: April 29, 1999.
William K. Hubbard,
Acting Director Commissioner for Policy.
[FR Doc. 99-11319 Filed 05-06-99; 8:45 am]
BILLING CODE 4160-01-F