Intensive Swine Production and Pork Safety

Abstract

Major structural changes in livestock production in developed countries, particularly intensive confinement production and increases in herd and flock sizes, have raised several societal concerns about the future directions and implications of livestock food production, including the safety of meat products. This review of the major parasitic and bacterial foodborne pathogens associated with pork production indicates that pork safety in the United States has improved demonstrably over recent decades. Most notably, changes in swine production methods have been associated with virtual elimination of risk of the foodborne parasites Taenia solium, Trichinella spiralis, and Toxoplasma gondii from pigs reared on modern intensive farms. This represents a substantial public health achievement that has gone largely unheralded. Regulatory changes have led to demonstrably lower prevalence of Salmonella on pork carcasses, but control of bacterial foodborne pathogens on farms remains a significant challenge. Available evidence does not support the hypothesis that intensive pork production has increased risk for the major bacterial foodborne pathogens that are common commensals of the pig (Salmonella, Campylobacter, Listeria, and Yersinia enterocolitica), or that pigs produced in alternative systems are at reduced risk of colonization with these organisms. However, pigs raised in outdoor systems inherently confront higher risks of exposure to foodborne parasites, particularly T. gondii.

Involvement of Toxoplasma gondii in reproductive disorders in Swiss pig farms

“…It is generally accepted, that the prevalence of T. gondii infection in pigs can vary according to their age and management system, being generally higher in older pigs and in pigs reared outdoors than in young pigs and pigs from bio-secure indoor farms, as they have an increased chance for contact with T. gondii (ingestion of oocysts or infected intermediate hosts, i.e. rodents or birds) [2,[9][10][11]. Interestingly, in this study no significant differences in the seroprevalences according to the housing system were observed.…”

Seroprevalence and risk factors for Toxoplasma gondii infection in pigs in southern Piauí

“…In farmed animals, such as sheep, pigs and goats, infection by T. gondii is common and can lead to great economic loss through stillbirths, miscarriages and birth defects (UZÊDA et al, 2004). Food-borne transmission of T. gondii is considered to be the most important route for human infection (PEREIRA et al, 2010;DAVIES, 2011), which occurs through the ingestion of tissue cysts while handling or eating raw or undercooked meat. Free-range meat production is a trend that may increase the risk of parasite-infection.…”

Yersinia enterocolitica Inhibits Salmonella enterica Serovar Typhimurium and Listeria monocytogenes Cellular Uptake

“…Food-borne pathogens offer an excellent venue for shedding light on alternative infectious outcomes that can emerge due to coinfection. Y. enterocolitica, S. Typhimurium, and L. monocytogenes are enteric pathogens that are known to colonize domesticated animals and are likely to participate in coinfections (58). In this report we demonstrated that Y. enterocolitica blocks the uptake of S. Typhimurium into epithelial cells in a T3SS-dependent manner but does not block S. Typhimurium uptake by macrophages.…”

“…SdiA increases the expression of the rck operon and a putative T3SS effector of unknown function, SrgE. It is not known if Y. enterocolitica AHL production is relevant to S. Typhimurium in nature, although both are prevalent in swine, where they presumably encounter one another (58). We tested the hypothesis that the SdiA regulon (rck and srgE) is used to reverse the host cell uptake blockade imposed by Y. enterocolitica.…”