In August 2022, the US Department of Agriculture (USDA) announced that it would be declaring Salmonella an adulterant in breaded and stuffed raw chicken products. These products will be considered adulterated when the presence of Salmonella exceeds one colony forming unit (CFU) per gram of breaded and stuffed raw chicken. By doing this, the Food Safety and Inspection Service (FSIS) of USDA would have the authority to recall affected products and ensure they are not sold to consumers.

“Since 1998, breaded and stuffed raw chicken products have been associated with up to 14 outbreaks and approximately 200 illnesses,” USDA said following its announcement. “Products in this category are found in the freezer section and include some chicken cordon bleu or chicken Kiev products. These products appear cooked, but they are heat-treated only to set the batter or breading, and the product contains raw poultry. Continual efforts to improve the product labeling have not been effective at reducing consumer illness.”

USDA-FSIS followed that announcement with the release of a proposed regulatory framework for a new strategy to control Salmonella contamination in poultry products and reduce foodborne illnesses attributed to these products. USDA Deputy Undersecretary Sandra Eskin acknowledged that Salmonella in poultry is a complex problem but said the agency had identified strategic actions FSIS could take that are likely to reduce Salmonella infections linked to consumption of poultry products. The proposed framework consists of three key components:

  • Requiring that incoming flocks be tested for Salmonella before entering an establishment;
  • Enhancing establishment process control monitoring and FSIS verification; and
  • Implementing an enforceable final product standard.

As part of its regulation making process, FSIS said the agency would determine whether a different standard for adulteration – such as zero tolerance or one based on specific serotypes – would better serve the purpose of protecting public health.

Consumer advocacy groups have urged USDA to declare certain “outbreak serotypes” of Salmonella to be adulterants in all meat and poultry. Proponents of this strategy say it would encourage increased monitoring efforts and ensure public health and safety.

In 2021, Center for Science in the Public Interest (CSPI) and Marler Clark LLP, a law firm that specializes in litigating foodborne illness complaints, petitioned FSIS requesting that the agency declare outbreak serotypes – including Salmonella Agona, Anatum, Berta, Blockely, Braenderup, Derby, Dublin, Enteritidis, Hadar, Heidelberg, I 4,[5],12:i:-, Infantis, Javiana, Litchfield, Mbandaka, Mississippi, Montevideo, Muenchen, Newport, Oranienburg, Panama, Poona, Reading, Saintpaul, Sandiego, Schwarzengrund, Senftenberg, Stanley, Thompson, Typhi, and Typhimurium – as adulterants in meat and poultry products.

Chicken cordon bleuThe USDA now considers Salmonella an adulterant in breaded and stuffed raw chicken products. (Source: ©HOMANK76 - STOCK.ADOBE.COM)

 

Research priorities

The announcements signaled USDA-FSIS’ resolve to reduce rates of foodborne illness outbreaks caused by Salmonella which have remained flat while overall rates of foodborne illnesses have fallen. It also was a sign that more research could inform some aspects of the agency’s new strategy to combat Salmonella illness outbreaks.

The US Poultry & Egg Association (USPOULTRY), Tucker, Ga., compiled a list of research priorities such as breeder management, food safety, animal welfare, employee safety, nutrition and other topics. USPOULTRY highlighted food safety research projects — some new and some ongoing — the association believes will help regulators as they develop frameworks and strategies for controlling Salmonella. For example, a previous study focused on enrichments (a culture that isolates and makes conditions for growth favorable to an organism) industry utilizes to determine the concentration of pathogens on raw poultry.

“There are multiple commercially available enrichment and non-enrichment-based Salmonella quantification methods,” said Denise Heard, DVM, MAM, ACPV and vice president, Research Programs at USPOULTRY. “Those have been developed to support the industry efforts to reduce the public health impact of Salmonella.

“In raw poultry products, those methods are specifically designed to determine the concentration of Salmonella in raw poultry products so that poultry producers can then in turn use the concentration data to take appropriate action about what to do with their products (and) the disposition of their products.”

However, Heard said, currently there is no publicly available research or data that shows the equivalency of those enrichments versus non-enrichment Salmonella quantification approaches. So, the objective of a recent USPOULTRY study funded in response to the FSIS declaring Salmonella an adulterant in breaded chicken products “…is to subject routine turkey and chicken samples to different Salmonella quantification testing with three commercially available methods currently being used, to provide real-world data for the evaluation of method equivalency,” Heard explained.

Another project USPOULTRY funded in the spring of 2022 that is ongoing and relevant considering the USDA-FSIS proposed framework is titled “Risk Assessment Comparing Alternative Approaches to Regulating Salmonella and Poultry by Public Health Impact Factors.” Not all Salmonella and poultry products have an impact on public health, but current USDA performance standards for raw poultry not only treat all Salmonella equally, but also treat all contamination levels equally, Heard said.

“This project that we’re funding asked the question, can we reduce foodborne illness by regulating Salmonella and poultry using metrics that account for different impacts of specific strains, or high levels on the risk of the disease,” she said. “So, the objectives for this project are to build a farm-to-fork, quantitative microbial risk assessment of Salmonella subtypes and poultry products incorporating different production strategies to comply with the performance standards, and then also to use the risk assessment to assess the likely impact on foodborne disease of performance standards for Salmonella levels and or specific strains.”

“So, Salmonella Kentucky rarely causes human disease,” she added, “so why would you treat Kentucky the same way that you’re treating Salmonella Infantis or something like that?”

Heard said the information gleaned from that research will be provided to FSIS as the agency pursues risk assessments and to the poultry industry to provide more information about how stakeholders can combat the Salmonella strains of most concern and the intervention strategies that are most appropriate to deal with them.

Production-side solutions

Also making the USPOULTRY list of research needs is development of vaccines that are proven effective against Salmonella strains.

An outbreak of Salmonella Reading exposed the need for effective control of the pathogen in turkey production; vaccination can reduce Salmonella in poultry. An investigation by the Atlanta-based Centers for Disease Control (CDC) and Prevention found 356 cases of Salmonella Reading in 42 states between November 2017 and March 2019. Among the 300 patients with information, one person died, and 132 individuals were hospitalized.

The outbreak strain was found in 178 samples of raw turkey products from 24 slaughter and 14 processing facilities over 21 states. However, a single, common supplier of the raw turkey products or live turkeys was not identified, according to the CDC.

In December, USPOULTRY and the USPOULTRY Foundation announced the completion of a funded research project in which Shawn Bearson, PhD, a microbiologist with the Food Safety & Enteric Pathogens Research Unit at the USDA, ARS, National Animal Disease Center, assessed the vaccine efficacy of two live-virus Salmonella vaccines, AviPro Megan Egg vaccine and an internally developed cross-protective BBS 866 DIVA vaccine.

Research findings showed that vaccination with BBS 866 or AviPro Megan Egg “...significantly reduced colonization by S. Reading in turkeys, indicating that these vaccines are cross-protective and could be a pre-harvest intervention strategy against this serovar,” the study said. “This would thereby potentially reduce Salmonella carriage into the human food chain, limit foodborne outbreaks, diminish the cost of meat product recalls to the industry, and provide the public with a safer food supply.”

“I know the turkey industry in particular will be very pleased with this new vaccine as well as the findings of a currently used vaccine and the ability that it has to reduce Salmonella Reading,” Heard said.