Foodborne pathogens are often difficult to control during food production. Salmonella, which causes more than a million illnesses in the United States each year, is particularly damaging. It can intelligently adapt to its environment to survive in extreme circumstances. In low humidity conditions, for example, Salmonella becomes even more heat resistant, creating a food safety hazard for meat and poultry products cooked in dry heat conditions.

To help alleviate this problem, the US Department of Agriculture in 2017 updated its industry guidelines to Appendix A. According to the new guidelines, a humidity level of 90% should be maintained during meat and poultry cooking process that takes less than an hour to ensure product safety.

Compliance with this new directive has been a problem for many processors, as smaller meat and poultry products, such as chicken nuggets and beef patties, are often cooked for short periods at high temperatures. using an impact oven, a continuous cooking system driven by a conveyor belt. When Salmonella are exposed to these dry heat methods, the bacteria dry out or dry out, making them more heat tolerant and better able to survive high temperatures. Processors needed a way to ensure the inactivation of Salmonella in their products without having to replace their existing impact furnaces, which are bulky and expensive equipment.

A team of researchers from UW-Madison, including Jeff Sindelar, professor and extension specialist in the Department of Animal and Dairy Sciences, and Kathy Glass, distinguished scientist and associate director of the Food Research Institute (FRI), decided to help solve this problem. , working with Meat Industry Advisor Bob Hanson and representatives from many of FRI’s industry partners including Hormel Foods, Johnsonville Sausage, Jones Dairy Farm, SugarCreek Packing, Tyson Foods and ConAgra.

In a study recently published in Biology of meat and muscles, the group shared the results of their collaborative effort to design, test and validate a new treatment method known as hydrated surface lethality (HSL) – which involves steam injection – that meets the new guideline from USDA without requiring major equipment modifications to impact existing ovens.

“The team designed an extensive series of experiments that tested this hypothesis for a range of chicken, pork and beef products using many different process conditions, and conducted these experiments in the FRI laboratories during several months, ”explained Hanson.

Believing that the pathogens hidden inside meat products were already continuously hydrated, the scientists decided to focus on the surface pathogens. They hypothesized that maintaining hydration on product surfaces for a sufficient period of time was the key to killing pathogens. By incorporating HSL steps during cooking to achieve wet bulb temperatures of 160 ° F or higher, researchers were able to inactivate salmonella in finished products. The research paper includes information on how to modify equipment to implement HSL, as well as simple parameters that can be used to validate the food safety of industrial cooking processes using newly modified equipment.

“From my perspective, I was so impressed with the effectiveness of the FRI group,” said Hanson. “This group worked together as a high performing team that thrived through collaboration. Everyone contributed to the success of the project, and it was completed on time and cost effectively. “

The research provides a viable solution that not only benefits processors but also ensures consumer safety, demonstrating the university’s positive reach throughout Wisconsin and beyond.

“It was a great project where we brought together academic and industry experts to find science-based, government-backed, industry-applicable solutions,” Sindelar said.