Epizootiology and Control Measures for Salmonella in Pigs

Campylobacteriosis, Salmonellosis, Yersiniosis, and Listeriosis as Zoonotic Foodborne Diseases: A Review

“…in slaughterhouses by direct or indirect contact with a carcass with the intestinal content or faeces, or through the production environment [ 115 ]. Pigs may be infected at the stage of breeding, via feed, infected by animals from other farms, from the environment, or by vectors such as insects, fleas, birds, dogs, or cats [ 129 ].…”

Non-typhoidal Salmonella in the Pig Production Chain: A Comprehensive Analysis of Its Impact on Human Health

“…This pig colonization can occur throughout all stages of pig production chain by horizontal (through external agents in the environment, e.g., rodents, birds, people, trucks, pets, other foodstuffs) and vertical transmission (e.g., from sow to piglet and from pig to pig at herd to slaughter). Additionally, a designated circular transmission (combination of vertical and horizontal transmission), which is a permanent cycle of contamination on a farm (e.g., environmental contamination through pig shedding and pig contamination through farm environment) can also determine pig colonization [11,13,32,33,34]. The presence of Salmonella in those healthy pig carriers (e.g., tonsils, gut and gut-associated lymphoid tissue) is suggested to be the main risk factor for the spread and transmission of these bacteria across pig production chain to humans: in pre-harvest (holding period of pig on the farm), in the harvest stage (during slaughter and further processing of meat carcasses) and in the post-harvest stage (during final preparation of pork meat and products thereof) [11,13,32,33,35,36].…”

“…These data have shown that breeding pigs may be a relevant source of Salmonella dissemination along the pig production chain (e.g., to slaughter pigs through trade and movement of live animals and contamination of holding, transport, lairage and slaughter facilities), leading to pork meat contamination and consequently to human infections [32]. In fact, high levels of Salmonella contamination occurred in slaughterhouses by diverse routes (e.g., pork meat carcasses cross-contamination, slaughter environment and equipment, meat handlers), as reported in diverse studies [11,13,39]. Another EU survey based on the analysis of quantitative microbiological risk assessment of Salmonella in slaughter and breeder pigs showed that an 80–90% reduction of Salmonella prevalence in lymph nodes should result in a comparable reduction in the number of human cases attributable to pork meat products [40].…”

“…Salmonellosis has been mostly associated with the consumption of poultry products, including eggs and egg products, at a global level [2,5,6,7,8,9,10]. However, pork meat has been considered one of the major food products of animal origin responsible for Salmonella transmission to humans in diverse countries, including industrialized ones [2,11,12,13]. In the EU, pork meat has been a common source of human salmonellosis cases (varying from 2% to 13%), after eggs and egg products [5,6,7,8].…”

“…In the EU, the successful implementation of mandatory Salmonella control programmes along poultry/egg production chain was responsible for the reduction of the prevalence of Salmonella serotypes considered relevant for public health, particularly S. Enteritidis [5,6,29]. In contrast to poultry production, where Salmonella control programmes are harmonized, for pig production each EU member state applies a specific national monitoring programme [5,6,13]. In addition, the intensive food production/farming and increased globalization of food supply (live animals and foodstuffs), with pork meat being one of the most consumed and traded meat products (pork exports increased in value by 18.2% from 2015 to 2016) [30,31], may trigger new problems regarding salmonellosis control.…”