Survey of intact and non-intact raw pork collected at retail stores in the mid-Atlantic region of the United States for the seven regulated serogroups of Shiga toxin-producing Escherichia coli

Authors: Jung, Yang Jin; Porto-Fett, Anna; Shoyer, Brad; Shane, Laura; Henry, Elizabeth; Osorio, Manuela; Luchansky, John

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2019
Publication Date: 11/1/2019
Citation: Jung, Y.N., Porto Fett, A.C., Shoyer, B.A., Shane, L.E., Henry, E.D., Osoria, M., Luchansky, J.B. 2019. Survey of intact and non-intact raw pork collected at retail stores in the mid-Atlantic region of the United States for the seven regulated serogroups of Shiga toxin-producing Escherichia coli. Journal of Food Protection. 82. https://www.doi.org/10.4315/0362-028X.JFP-19-192.
DOI: https://doi.org/10.4315/0362-028X.JFP-19-192

Interpretive Summary: According to the USDA Food Safety and Inspection Service (USDA-FSIS), pork is the most consumed meat worldwide. Although it is not a common vehicle for food borne illness due to Shiga toxin-producing cells of Escherichia coli (STEC), over the last 25 years there have been a handful of STEC outbreaks caused by pork products. As such, it is not so surprising that STEC have been recovered from swine and raw pork products, but such isolates have only rarely displayed the target surface antigens and associated virulence genes to be confirmed as the serogroups of STEC most likely to cause human illness. Since the true prevalence of the seven serogroups of STEC (O26, O45, O103, O111, O121, O145, or O157:H7; STEC-7) responsible for most food borne illnesses has not been fully elaborated for raw pork products, we surveyed raw pork samples from grocery stores in Pennsylvania, Delaware, and New Jersey for the presence of STEC-7. None of the 514 raw pork samples (i.e., 395 ground or tenderized products and 119 whole muscle products) harbored a viable isolate of STEC-7 possessing the required virulence genes or cell surface markers. Thus, based on the lack of scientific or epidemiological data to the contrary, and in light of our findings that STEC-7 were not recovered from raw pork products, it would seem that the risk to human health caused by STEC in retail pork is relatively low in the mid-Atlantic region of the U.S.

Technical Abstract: A total of 514 raw pork samples (395 ground/non-intact and 119 intact samples) were purchased at retail stores in Pennsylvania, Delaware, and New Jersey between July and December of 2017. All raw pork samples were screened for serogroup O26, O45, O103, O111, O121, O145, or O157:H7 cells of Shiga toxin-producing Escherichia coli (STEC-7) using standard microbiological and molecular methods. In short, 5.3% (21 of 395 samples) of the ground/non-intact pork samples and 3.4% (3 of 119 samples) of the intact pork samples tested positive via the BAX system real-time PCR assay for the stx and eae virulence genes and for the somatic O antigens for at least one of the STEC-7 serogroups. However, none of these 24 presumptive positive pork samples yielded a viable isolate of STEC displaying a STEC-7 serogroup-specific surface antigen in combination with the stx and eae genes. These data suggest that serogroups O26, O45, O103, O111, O121, O145, or O157:H7 of STEC are not common in retail raw pork samples in the mid-Atlantic region of the U.S.