An Overview of Shiga-Toxin Producing Escherichia coli Carriage and Prevalence in the Ovine Meat Production Chain

Abstract

Shiga-toxin producing Escherichia coli (STEC) are zoonotic foodborne pathogens that are capable of causing serious human illness. Ovine ruminants are recognized as an important source of STEC and a notable contributor to contamination within the food industry. This review examined the prevalence of STEC in the ovine food production chain from farm-to-fork, reporting carriage in sheep herds, during abattoir processing, and in raw and ready-to-eat meats and meat products. Factors affecting the prevalence of STEC, including seasonality and animal age, were also examined. A relative prevalence can be obtained by calculating the mean prevalence observed over multiple surveys, weighted by sample number. A relative mean prevalence was obtained for STEC O157 and all STEC serogroups at multiple points along the ovine production chain by using suitable published surveys. A relative mean prevalence (and range) for STEC O157 was calculated: for feces 4.4% (0.2-28.1%), fleece 7.6% (0.8-12.8%), carcass 2.1% (0.2-9.8%), and raw ovine meat 1.9% (0.2-6.3%). For all STEC independent of serotype, a relative mean prevalence was calculated: for feces 33.3% (0.9-90.0%), carcass 58.7% (2.0-81.6%), and raw ovine meat 15.4% (2.7-35.5%). The prevalence of STEC in ovine fleece was reported in only one earlier survey, which recorded a prevalence of 86.2%. Animal age was reported to affect shedding in many surveys, with younger animals typically reported as having a higher prevalence of the pathogen. The prevalence of STEC decreases significantly along the ovine production chain after the application of postharvest interventions. Ovine products pose a small risk of potential STEC contamination to the food supply chain.

Potential Zoonotic Pathovars of Diarrheagenic Escherichia coli Detected in Lambs for Human Consumption from Tierra del Fuego, Argentina

“…Previous studies have reported prevalence in ovine, which were observed to be considerably variable between authors. McCarthy et al (2021) [ 28 ] calculated the relative prevalence of STEC in ovine feces from published data, which was established in 33.3% with ranges from 0.9% to 90.0%; according to this analysis, our prevalence results at 26.63% were similar. Despite the fact that we used a specific diagnosis route for STEC O157 detection, which included a selective enrichment, immunocromatography, and IMS, we were unable to detect STEC O157 in contrast to other authors [ 29 , 30 , 31 ].…”

Faecal Carriage of Escherichia coli 0157:H7 Serotype by Free-Ranged and Confined Small Domestic Ruminants within Cross River State, Nigeria

“…"The diagnostic automation Enzyme-linked immunosorbent assay (ELISA) technique was used for the qualitative detection of E. coli 0157 antigens in all enriched samples" [22].…”

“…More recently, feces of small domestic ruminants such as sheep and goats have emerged as important sources of E. coli O157:H7 implicated in human infections particularly with the widespread of petting farms and the increasing use of sheep and goats as major sources of meat [18][19][20][21][22][23]. However, information on this pathogen associated with small domestic ruminants in Nigeria still remain scanty and most often conducted in the Northern part of the country [21,[24][25][26].…”

Occurrence, Serotypes and Virulence Characteristics of Shiga-Toxin-Producing Escherichia coli Isolates from Goats on Communal Rangeland in South Africa

“…Domestic ruminants including cattle, sheep, and goats are the main reservoirs of STEC [ 2 , 3 , 4 , 5 ]. Ingestion of contaminated meat, dairy products, vegetables, and water is a risk factor for acquiring STEC infection in humans [ 2 , 6 , 7 ].…”