Editor’s note: This is the second of a two-part opinion piece. To read part one, please click here.

In the previous article, I wrote about the decades-old public health problem of poultry-borne salmonellosis. This article will propose declaring the virulent strains that are pathogenic to humans as adulterants and the benefits of doing so.

Regulatory policies for other foodborne pathogens recognize consumer’s inability to handle them. The Code of Federal regulations, 9 CFR 311.2-39 describes a number of conditions for declaring meat carcasses adulterated, including: tuberculosis, arthritis, and odors. The poultry regulations 9 CFR, 381.80 et seq are similar. The Meat Inspection Regulations, 9 CFR 315.2 permit some meat products that are found adulterated under 311 to be passed for cooking – under the oversight of federal inspections, not in consumers’ kitchens. In 1995, the top administrator of the USDA’s Food Safety and Inspection Service (FSIS), Craig Reed, use that principle in his letter permitting lots of ground beef containing Escherichia coli O157:H7 to be cooked in a federal establishment – not in consumers’ kitchens.

Treatment of raw meat and poultry by cooking, irradiation, or high pressure processing would eliminate consumer exposure to those pathogens. However, one of the primary sources of foodborne pathogens now is contaminated produce. A growing body of scientific literature indicates a major source of these pathogens is food animal production via air 2, water 1, and manure 4. (These are only three recent papers of many). The 2018 meeting of the International Association for Food Protection (IAFP) in Salt Lake City had more than 20 sessions addressing preharvest contamination of soil, water and produce. There is also a large body of scientific literature on preharvest interventions in animals including isolation, competitive exclusion, probiotics, prebiotics, and vaccination. 

Interventions cost and thus, producers need incentives. Incentives include altruism, regulations, customer specifications, and litigation. A 2018 IAFP Round Table “RT9: Do Lawsuits Play a Productive Role in Advancing Food Safety?” suggested that customer specifications and regulations produced faster results; lawsuits were too far in the future. The COSTO and Walmart speakers said customer specifications are effective. Regulation has had some effect on E. coli O157:H7 in beef, but certainly not eliminated it in either commerce or preharvest.6 One can only speculate what the results would be if FSIS had not declared it an adulterant in 1994. We know more each year what the effect is of not declaring outbreak strains of Salmonella as adulterants.

The FSIS has the legal means to prevent these adulterants from entering commerce. The Meat and Poultry Inspection Acts 8-9 empower FSIS inspectors to conduct ante mortem and post mortem inspection of all animals before processing them into food. Traditionally, that has been visual inspection but not always. FSIS’s 2013 “Compliance Guide For Residue Prevention” uses laboratory results to compile a list, “The Residue Repeat Violator List.” It is composed of suppliers who have had more than one residue violation in the preceding 12 months. Thus, animals from a producer on that list present a “hazard reasonably likely to occur.” The HACCP (Hazard Analysis and Critical Control Point) rules require establishments to have controls to prevent any product with violative residues from entering commerce. Failure to do so is a violation of 9 CFR 417.6. FSIS can sample carcasses or live animals and the laboratory will report any violation to Field Operations for action. 

The principle used for residues could be applied to outbreak strains of certain bacterial pathogens also. These strains are adulterants as defined by both the Inspection Acts and the Code of Federal Regulations. FSIS routinely samples carcasses and products for pathogenic bacteria. When an outbreak strain is detected and traced back to an establishment, the establishment can identify the producer and that producer would be put on a “Adulterant Carrier List.” Future animals from that producer and their products must either be treated to inactivate any adulterants or tested (ICMSF Case 15) until the producer has implemented validated controls and verified their effectiveness to prevent future contamination. If the establishment cannot identify the producer, then all product from that establishment would be treated or tested under ICMSF Case 15 to prevent any adulterants from entering commerce.

This would be a harsh rule and FSIS would likely be sued by the industry. The outcome should be similar to Texas Food Industry Ass’n v. Espy7 where E. coli O157:H7 was found to be an adulterant in ground beef because consumers would eat the product rare. So why not Salmonella? The difference would be that FSIS could use the half century of scientific findings that cross contamination within consumer’s kitchens is a major source of foodborne illnesses, not just undercooking. Thus poultry and other meat products would be included.

The outcome of FSIS promulgating such a regulatory policy would be that preharvest control of pathogenic bacteria in food animal production would begin to be addressed. This action would begin to reduce the environmental contamination that reaches produce fields via waterways and even highways5.

Assays for pathogens have advanced rapidly in the past decade3. Methods are more rapid, sensitive, and specific. The FSIS, processors, and producers can use these methods to rapidly verify that interventions are working and adulterants are not being found in products.

It would be wonderful if altruism was the incentive for preventing adulterants from entering commerce. Alas, we do not live in that world. But let us take USC 602 to heart and apply it to preharvest control.


1. Alegbeleye OO, Singleton I, Sant’Ana AS. 2018. Sources and contamination routes of microbial pathogens to fresh produce during field cultivation: A review. Food Microbiology. 73: 177-208. https://doi.org/10.1016/j.fm.2018.01.003

2. Berry ED, Wells JE, Bono JL, Woodbury BL, Kalchayanand N, Norman KN, Suslow TV, López-Velasco G, Millner PD. 2015. Effect of proximity to a cattle feedlot on Escherichia coli O157:H7 contamination of leafy greens and evaluation of the potential for airborne transmission. Appl Environ Microbiol 81:1101–1110. doi:10.1128/AEM.02998-14.

3. Besser, John M. 2018. Salmonella epidemiology: A whirlwind of change. Food Microbiology 71:55-59.

4. Heredia, Norma, Santos, García. 2018. Animals as sources of food-borne pathogens: A review. Animal Nutrition. In Press  https://doi.org/10.1016/j.aninu.2018.04.006

5. Seedorf J, Schmidt RG.. 2017.  The simulated air flow pattern around a moving animal transport vehicle as the basis for a prospective biosecurity risk assessment. Heliyon 3:00358

6. Swaggerty, Christina L., Ester Grilli, Andrea Piva, Nicolae Corcionivoschi, Steven C. Ricke, Todd R. Callaway. 2018. The First 30 Years of Shiga Toxin–Producing Escherichia coli in Cattle Production: Preharvest Intervention Strategies.  Food and Feed Safety Systems and Analysis- Chapter 8. Pages 133–151 https://doi.org/10.1016/B978-0-12-811835-1.00008-7

7. Texas Food Industry Ass’n v. Espy, 870 F. Supp. 143 (W.D. Tex. 1994) US District Court for the Western District of Texas – 870 F. Supp. 143 (W.D. Tex. 1994) December 13, 1994

8. 21 U.S. Code § 455. Inspection in official establishments (Poultry Inspection)

9. 21 U.S. Code § 603 – Examination of animals prior to slaughter; use of humane methods (Meat Inspection)

About the author: Carl Custer is an independent consultant for food safety microbiology. He retired from The U.S. Department of Agriculture’s FSIS in 2007 after more than 34 years as a bench and a desk scientist. The food safety issues he worked on include:

  • Carl Custer

    Inhibition of Clostridium botulinum;

  • Inhibiting nitrosamine formation;
  • Analysis and inactivation of Trichinella spiralis;
  • Physics and microbiology of cooling heated foods;
  • Thermal and non-thermal inactivation of bacterial pathogens in traditional and ethnic foods;
  • Predictive microbiology;
  • The microbiology and safety of fermented and dry-cured meat products; and
  • HACCP development and implementation for both processing and slaughter

These issues included developing the scientific basis for regulatory policy development and rule promulgation. Carl also served as a trainer for FSIS inspectors, the FSIS Hotline, retail processors and inspectors, small farm processors, and country ham processors. Custer is a lifetime member of the International Food Protection Association (IAFP) and the American Society for Microbiology.  He was also a member of the Food Microbiology Research Conference executive board for twelve years, serving as the chair for two years.

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