Microbiological Testing of AMS Purchased Meat, Poultry and Egg Commodities

Background

Under authority of the Richard B. Russell National School Lunch Act, the Agricultural Marketing Service (AMS) works with its sister Agency, the Food and Nutrition Service (FNS), to purchase and distribute foods through various Federal nutrition assistance programs. These programs include, but are not limited to, Commodity Supplemental Food Program, Food Distribution Program on Indian Reservations, Temporary Emergency Food Assistance Program and the National School Lunch Program (NSLP), which provides nutritious meals to over 31 million school children in over 100,000 participating public and private nonprofit schools and institutions each year.

As part of its food purchase programs, AMS oversees microbiological testing activities to ensure safe, wholesome commodities are procured. Boneless beef, ground beef, diced cooked chicken, and egg products are tested for the presence of standard plate counts (mesophilic aerobic plate counts), coliform bacteria, generic Escherichia coli, and other indicators of process control; and for foodborne pathogens, including Salmonella spp., Listeria monocytogenes, E. coli O157:H7, and Non-O157 STECs (O26, O45, O103, O111, O121, O145).

AMS continually reviews its microbiological testing programs through internal audits, soliciting reviews from independent scientific bodies, including the National Academies and the National Advisory Committee on Microbiological Criteria for Foods, and working with stakeholders, with the intent of constantly strengthening its purchase programs and ensuring that its requirements are based on the best available science.

The data generated under these testing programs are used to determine the eligibility of vendors to supply food to Federal nutrition assistance programs, and to continually refine and strengthen the microbiological testing requirements for AMS purchase programs. Moreover, summaries of this data provide an overall picture of vendor performance.

Sample Collection and Processing

AMS sampling procedures and frequencies are described in the specification documents of each commodity (Boneless Beef, Ground Beef, Cooked Diced Chicken, and Egg Products). Samples are collected and processed by establishment personnel and tested using laboratory methods specified by AOAC International, the Food Safety and Inspection Service (FSIS) Microbiological Laboratory Guidebook, and/or the Food and Drug Administration (FDA) Bacteriological Analytical Manual. Samples are collected in areas free from air currents on work surfaces that have been cleaned and sanitized. Samples are collected in an aseptic manner assuring that no foreign sources of microbial contamination are introduced. Tools used for sampling are sterilized before use and protected from outside contamination during use. Samples are then placed into sterilized containers and placed in refrigerators or freezers. Refrigerated samples are shipped to laboratories on ice in insulated containers, while frozen samples are shipped packed in dry ice in insulated containers using overnight courier service. Samples are identified by FSIS establishment number, production/sample date, and lot/sublot number(s).

Laboratory Analysis

AMS contracts with commercial laboratories to perform microbiological testing of its commodities. As part of the contractual process, AMS does in-depth audits of the laboratories to ensure they are capable and equipped to conduct the necessary analyses. Each laboratory is audited annually by representatives of the AMS Science and Technology program. Audit specifications include accreditation to International Standards Organization (ISO) 17025 (pdf) and participation in the American Proficiency Institute’s or similar sample proficiency program. Corrective actions are required to remedy any deficiencies identified during audits and subsequent confirmation of the implementation of corrective actions is necessary to gain final audit approval.

Microbiological Testing Results

Boneless Beef

Boneless beef produced by AMS vendors is sampled and tested for the following indicator microorganisms: standard plate count (mesophilic aerobic plate counts), total coliforms, and generic E. coli, with critical limits of 100,000 colony forming units (cfu)/gram (g), 1,000 cfu/g, and 500 cfu/g, respectively. Any lot of product found to exceed any of these control limits is rejected for purchase by AMS.

Boneless beef is also tested for E. coli O157:H7, Salmonella, and Non-O157 STECs (O26, O45, O103, O111, O121, O145), with zero tolerance.

Ground Beef

Ground beef produced by AMS vendors is sampled and tested for the following indicator microorganisms: standard plate count (mesophilic aerobic plate counts), total coliforms, and generic E. coli, with critical limits of less than 100,000 cfu/g, 1,000 cfu/g, and 500 cfu/g, respectively. Any lot/sub-lot of product found to exceed any of these control limits is rejected for purchase by AMS.

Ground beef is also tested for E. coli O157:H7 and Salmonella, with zero tolerance.

For a detailed discussion of boneless and ground beef testing results, see Doerscher DR, Lutz TL, Whisenant SJ, et al. (2015) Microbiological Testing Results of Boneless and Ground Beef Purchased for the National School Lunch Program, 2011 to 2014. J. Food. Prot. 78:1656-63 (View the Abstract).

Cooked Diced Chicken

Cooked diced chicken produced by AMS vendors is sampled and tested for the following indicator microorganisms: standard plate count (mesophilic aerobic plate counts), total coliforms, generic E. coli, and Staphylococcus (S.) aureus, with critical limits of 1,000 cfu/g, 50 cfu/g, 10 cfu/g, and 10 cfu/g, respectively. Any lot of product found to exceed any of these control limits is rejected for purchase by AMS.

Cooked diced chicken is also sampled and tested for Salmonella and L. monocytogenes, with zero tolerance.

Egg Products

Unpasteurized liquid whole eggs produced by AMS vendors are sampled and tested for the following indicator microorganisms: standard plate count (mesophilic aerobic plate counts), total coliforms and generic E. coli with critical limits of 100,000 cfu/g of sample, 5000 cfu/g, and 1,000 cfu/g, respectively.

All purpose egg mix and frozen pasteurized whole eggs produced by AMS vendors are sampled and tested for the following indicator organisms: standard plate counts (mesophilic aerobic plate counts) and total coliforms, with critical limits of 1,000 cfu/g and 10 cfu/g respectively; and for Salmonella, with zero tolerance.

Additional Resources