#18-049

Complete

Date Full Report Received

01/08/2021

Date Abstract Report Received

01/08/2021

Investigation

Institution:
Primary Investigator:

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Several products made from pork trim are currently being sampled by USDA FSIS under their Raw Pork Products Sampling Program Phase II (USDA FSIS Notice 30-17). This proposal intends to evaluate the impact of commercially viable interventions on reducing non-typhoidal Salmonella on pork trim and on ground products made from pork trim. In addition, it will evaluate sampling plans and provide statistical comparisons between the plans, in regard to their abilities to provide reliable information to processors. In 2015, there was an outbreak of Multidrug-Resistant Salmonella I 4,[5],12:i:- infections linked specifically to roaster pigs, with 134 confirmed cases (see https://www.cdc.gov/salmonella/pork-08-15/ ). All of the pigs were processed at the same federally inspected establishment in Washington State. The establishment would be classified as “very small” by USDA Food Safety and Inspection Service (FSIS), and although they were following standard industry practices, they were not using any microbial interventions. It was suggested by several individuals at both USDA FSIS and the Centers for Disease Control that perhaps this serovar was unusually heat resistant, which is why it survived cooking and caused the outbreak. Alternately it was suggested that the bacterium could have been located in the lymph nodes, and this combined with a hypothetical increased heat resistance could have contributed to the outbreak.

The research reported here demonstrates there is no evidence to suggest that Salmonella serovar I 4,[5],12:i:- presents a new or unique challenge to fresh pork. The responses of a mixed culture of different isolates of Salmonella serovar I 4,[5], 12:i- was evaluated for susceptibility to carcass interventions, survival during refrigerated storage and thermal resistance after refrigerated storage.
There were no observed differences in the response of a mixed culture of different isolates of Salmonella serovar I 4,[5], 12:i- when compared to mixed culture of reference Salmonella serovars. Based on these studies, there is no evidence to suggest that Salmonella serovar I 4,[5],12:i:- presents a new or unique challenge to fresh pork.

Key Findings:
• The response of Salmonella serovar I 4,[5],12:i:- to commonly used pork carcass interventions was not different from the response of common Salmonella serovars. There is no evidence to suggest that Salmonella serovar I 4,[5],12:i:- presents a unique challenge to pork carcass decontamination.
• The survival of Salmonella serovar I 4,[5],12:i:- during refrigerated storage in ground pork was not different from the survival of common Salmonella serovars. There is no evidence to suggest that Salmonella serovar I 4,[5],12:i:- presents a unique challenge during the refrigerated storage of pork.
• The heat resistance of Salmonella serovar I 4,[5],12:i:- during refrigerated storage in ground pork was less than the heat resistance of common Salmonella serovars. There is no evidence to suggest that Salmonella serovar I 4,[5],12:i:- presents a unique challenge during cooking of pork, and does in fact suggest that Salmonella serovar I 4,[5],12:i:- may be less of a risk than the common Salmonella serovars.
• The heat resistance of both common Salmonella serovars and Salmonella serovar I 4,[5],12:i:- decreased during refrigerated storage. All of the Salmonella serovars evaluated in this study were less heat resistant after 14 days storage at 5oC.
• General Conclusion: Based on these studies, there is no evidence to suggest that Salmonella serovar I 4,[5],12:i:- presents a new or unique challenge to fresh pork.