Salmonella enterica 4,[5],12:i:−, an Emerging Threat for the Swine Feed and Pork Production Industry

Abstract

Salmonella continues to be a significant cause of foodborne illnesses in human medicine. The Centers for Disease Control and Prevention reported Salmonella as the second leading cause of foodborne illness in the United States, and the leading cause of both hospitalizations and deaths. Salmonella enterica 4,[5],12:i:- (STM) is a monophasic variant of S. Typhimurium and it is an emerging threat to both human and animal health. STM was first identified in the 1980’s from poultry products and has become increasingly prevalent in meat products including pork. STM has also been identified in swine farms as well as feed manufacturing environments and feed itself. Similar pulse-field gel electrophoresis profiles have been observed between human clinical cases and the STM samples originating from swine feed. These related profiles suggest a link between swine ingesting contaminated feed and the source of foodborne illness in human. The objective of this article was to better understand the history of STM and the possible pathway between swine feed to the household table. Continued research is necessary to better understand how STM can enter both the feed supply chain and the pork production chain to avoid contamination of pork products destined for human consumption.

Risk-Benefit Assessment of Feed Additives in the One Health Perspective

“…Therefore, while uncertainties on the available analytical methods prevent a robust exposure assessment, data indicate that the use of FA as preservative in feedingstuffs may lead to a limited increase of residues in edible tissues and products with little impact, if any, on the overall consumer exposure. Hence, FA under the proposed conditions of use does not lead to an appreciable risk for consumers ( 64 – 66 ).…”

“…The available residue studies confirmed that the use of FA in feeds increased the concentrations in meat and milk, however the concentrations found in the residue studies were still in the range of the reported background concentrations in foods. Literature data indicate a contribution <20% by FA residues (from whatever source) in foods of animal origin to the overall dietary intake of FA ( 64 , 65 ). Therefore, while uncertainties on the available analytical methods prevent a robust exposure assessment, data indicate that the use of FA as preservative in feedingstuffs may lead to a limited increase of residues in edible tissues and products with little impact, if any, on the overall consumer exposure.…”

“…In the EU, short-term occupational exposure limits for FA based on irritation have been recommended. However, no safe level for long-term exposure of skin, eyes and respiratory system could be established as FA is a potent sensitiser and no threshold for tumor induction could be identified, as the mechanism of carcinogenesis is unclear ( 64 , 65 ). Due to the strong reactivity of FA with proteins and DNA, the carcinogenic action of FA at the contact site (nasopharyngeal and sinonasal cancers) can be due to a direct genotoxic effect, to non-genotoxic events associated to chronic irritation or to a combination of both mechanisms ( 64 , 65 ).…”

“…The demonstration of a uniquely non-genotoxic mode of action would theoretically allow the setting of a threshold for carcinogenesis; however non-irritant local concentrations of FA are known to produce DNA adducts, a lesion causally related with genotoxic carcinogenicity. Considering that the contribution of FA adducts to carcinogenicity cannot be ruled out, a threshold for cancer induction cannot at present be envisaged ( 64 , 65 ).…”

“…In addition, whereas FA induces reproductive toxicity in avian species ( 65 ), the safety in reproducing farm animals could not be established due to the lack of studies. No tolerance studies in cattle were available, but severe gross- and microscopic lesions of the alimentary tract compatible with clinical symptoms were recorded in calves fed formalin-treated skimmed milk; therefore no safe concentration can be established for veal calves ( 64 , 65 ).…”