The presence of Salmonella in raw, frozen and breaded chicken products in Canada, as well as associated human salmonellosis cases, decreased significantly after the Canadian Food Inspection Agency (CFIA) enhanced its regulation of these products in 2019, according to a study published in Epidemiology and Infection. The study was authored by experts at the Public Health Agency of Canada’s Center for Foodborne, Environmental, and Zoonotic Infectious Diseases.

The Issue of Salmonellosis Linked to Raw, Frozen and Breaded Chicken Products

In Canada, nontyphoidal S. enterica is a leading cause of foodborne illness, and epidemiological investigations of foodborne salmonellosis cases between 2000 and 2010 identified raw, frozen and breaded chicken products as a significant source of illness. Recent estimates show these types of chicken product to be responsible for approximately 12.9 percent of Canadian salmonellosis cases from 2000–2010. Between April 2017 and April 2019 alone, whole genome sequencing (WGS) directly linked 12 outbreaks comprising 285 cases of salmonellosis to raw, frozen and breaded chicken products. This issue could partly be due to the fact that consumers believe these raw products to be ready-to-eat (RTE); a 2018 study found that 35 percent of Canadians mistakenly believed raw, frozen and breaded chicken products to be pre-cooked for reheating.

To address the issue of salmonellosis linked to raw, frozen and breaded chicken products, in April 2019, CFIA implemented a requirement for industry to implement control measures at manufacturing/processing to reduce the presence of Salmonella to undetectable levels in certain types of these products (i.e., non-intact, raw, and breaded par-fried products like chicken nuggets and popcorn chicken, sold at retail). Such control measures could include a validated cooking process resulting in a RTE frozen product, implementation of a testing program to demonstrate undetectable levels of Salmonella, or a combination of both. Industry could also implement a Salmonella test-and-hold program for finished products.

The Effectiveness of CFIA’s 2019 Requirements

To understand the impact of CFIA’s April 2019 requirements for industry to control Salmonella levels in certain raw, frozen and breaded chicken products, researchers estimated the proportion of salmonellosis cases attributable to these products prior to and after the implementation of the regulation. The researchers used data from two Canadian enteric disease surveillance systems, the National Enteric Surveillance Program and FoodNet Canada. The data included human cases of salmonellosis, and surveillance for Salmonella in retail foods.

Analysis of the surveillance data for retail samples showed the prevalence of Salmonella in raw, frozen and breaded chicken products fell from 28 percent to 2.9 percent after April 2019. The researchers found that the remaining presence of Salmonella in these products after April 2019 was largely due to those products not covered in the new requirement, but still included in FoodNet Canada retail sampling activities.

Moreover, there was a 23 percent decline in salmonellosis incidence after April 2019, estimating that 26 percent of salmonellosis cases in the pre-intervention period were attributed to raw, frozen and breaded chicken products. Overall, the researchers concluded that CFIA’s 2019 requirement for raw, frozen and breaded chicken products was successful at substantially reducing Salmonella in these products at retail, and significantly contributed to a reduction in human salmonellosis incidence.

Efforts to Control Salmonella in Raw, Frozen and Breaded Chicken Products in the U.S.

The issue of salmonellosis cases attributable to raw, frozen and breaded chicken products is not limited to Canada. In the U.S., these products represented approximately 5 percent of all chicken-associated Salmonella outbreaks between 1998 and 2020, despite only accounting for less than 0.15 percent of the U.S. chicken supply, according to the U.S. Department of Agriculture (USDA). Since 1998, USDA’s Food Safety and Inspection Service (FSIS) and its public health partners have investigated 14 salmonellosis outbreaks comprising approximately 200 illnesses associated with these products.

In this context, in April 2024, USDA-FSIS finalized a determination declaring Salmonella an adulterant in raw, breaded and stuffed, not-ready-to-eat chicken products at levels exceeding 1 colony forming unit per gram (CFU/g). This action by FSIS is part of a greater strategy by the agency to reduce human cases of salmonellosis attributable to chicken; in July 2024, USDA-FSIS published a revision to its proposed regulatory framework for Salmonella in raw poultry, setting an enforceable final product standard for the pathogen at certain levels in a range of product types.