Background:

Food destined for human consumption, including meat and poultry, are known to harbor enteric bacteria. Antimicrobial resistance among these foodborne bacteria has been documented and may be associated with the use of antimicrobial agents in food animals. These bacteria may include organisms such as Salmonella , Campylobacter , E. coli , and Enterococcus . Retail meats represent a point of exposure close to the consumer and, when combined with data from slaughter plants and on-farm studies, provides insight into the prevalence of AR in foodborne pathogens originating from animals. To gain a better understanding of AR among enteric bacteria in the food supply, FoodNet and NARMS monitor antimicrobial susceptibility/resistance phenotypes in bacteria isolated from retail meats.

NARMS retail meat surveillance is an ongoing collaboration between the U.S. Food and Drug Administration (Center for Veterinary Medicine ), the Centers for Disease Control and Prevention, and in 2002, six of the 11 current FoodNet laboratories: Connecticut , Georgia , Maryland , Minnesota , Oregon , and Tennessee. The primary purpose of the NARMS retail meat surveillance program is to determine the prevalence of antimicrobial resistance among foodborne pathogens and commensal organisms, in particular, Salmonella, Campylobacter, Enterococcus and E. coli, recovered from retail foods of animal origin. The results generated by the NARMS retail meat program will establish a reference point for analyzing trends of antimicrobial resistance among these foodborne bacteria. Inferences concerning likelihood of human exposure to various species of bacteria should not be made on the basis of species prevalence for all meat types combined.

FoodNet is the principal foodborne disease component of CDC's ( EIP ; http://www.cdc.gov/foodnet/). It is a collaborative project of the CDC, eleven EIP sites ( California , Colorado , Connecticut , Georgia , New York , Maryland , Minnesota , Oregon , Tennessee , Texas and New Mexico ), the U.S. Department of Agriculture (USDA) , and the Food and Drug Administration (FDA). The project consists of active surveillance for foodborne diseases and related epidemiologic studies designed to help public health officials better understand the epidemiology of foodborne diseases in the United States . The NARMS/FoodNet Retail Food Study was developed to monitor the presence of AR among E. coli , Salmonella , Campylobacter , and Enterococcus from convenience samples of fresh meat and poultry purchased monthly from grocery stores in the participating States. These isolates were then subjected to standardized antimicrobial susceptibility testing methods in order to determine the prevalence of resistance.

Retail meat sampling :

For calendar year 2002, retail meat sampling started in January of 2002 for five of the six participating FoodNet laboratories, with the exception of Oregon . Oregon did not join the NARMS retail meat program until the last quarter (September to December) of 2002. For each of the FoodNet sites, samples were purchased monthly, with as many different stores as possible visited each month. The object was to purchase as many different brands of fresh (not frozen) meat and poultry as possible. A total of 40 food samples were purchased per month including 10 samples each of chicken breast, ground turkey, ground beef, and pork chops. For each meat and poultry sample, the FoodNet sites recorded the store name, brand name, lot number (if available) sell-by date, purchase date and lab processing date on log sheets (appendix A-5). Additional information with regard to whether or not the meat or poultry was ground or cut in-store was also collected, if possible. Samples were kept cold during transport from the grocery store(s) to the laboratory (appendix A-6).

Microbiological analysis :

In the laboratory, samples were refrigerated at 4 ° C and processed no later than 96 hours after purchase. After microbiological examination, recordings were made on the log sheets whether or not the meat and poultry samples were presumptively positive for Salmonella , Campylobacter , E . coli , and Enterococcus . Each laboratory used essentially the same procedure for sample collection (appendix A-6). Retail meat and poultry packages were kept intact until they were aseptically opened in the laboratory at the start of examination. For chicken and pork samples, one piece of meat was examined, whereas, 25 g of ground product was examined for ground beef and ground turkey samples. The analytical portions from each sample were placed in separate sterile plastic bags, 250 mL of buffered peptone water was added to each bag, and the bags were vigorously shaken. Fifty mL of the rinsate from each sample was transferred to separate sterile flasks (or other suitable sterile containers) for isolation and identification of Salmonella , Campylobacter , E. coli , or Enterococcus using standard microbiological procedures (appendix A-6). Once isolated and identified, bacterial isolates were sent to FDA's CVM Office of Research for further characterization including species confirmation, antimicrobial susceptibility testing and PFGE analysis (S almonella and Campylobacter only).

Meat and poultry rinsates were cultured for the presence of Salmonella and Campylobacter at all six FoodNet sites. Additionally, at four of the six FoodNet laboratories ( Georgia , Maryland , Oregon , and Tennessee ), meat and poultry rinsates were cultured for the presence of E. coli and Enterococcus.

NARMS retail meat working group, 2002

U.S. Food and Drug Administration

Centers for Disease Control and Prevention

Acknowledgements

Much thanks to Joanne Kla for editorial assistance, and Deborah Brooks, Michelle Talley and Stephanie Dove for providing outstanding web support to the NARMS program.

Contact : Dr. David G. White, dwhite@cvm.fda.gov

Suggested citation:

U.S. FDA, Center for Veterinary Medicine. National Antimicrobial Resistance Monitoring System for Enteric Bacteria (NARMS): NARMS Retail Meat Annual Report, 2002. Rockville , MD : U.S. Department of Health and Human Services, FDA, 2004.