Review of the Literature


Pre-slaughter Interventions to Reduce Foodborne Illness Caused by Salmonella Dublin: A Thematic Review

( Jane Lewis )

The incidence of cattle pathogen, Salmonella Dublin, has increased in the United States in recent years and concurrent foodborne infections in humans have been associated with beef, milk, and cheese consumption. Since treatment for this serovar is complicated by multi-drug resistance, more severe outcomes are likely for those infected. The purpose of this study was, therefore, to evaluate pre-harvest interventions that may reduce S. Dublin shedding in cattle at the time of slaughter. A review of the scientific literature observed that, although specific feeds and additives were associated with increased levels of Salmonella shedding, the incidence was decreased through direct fed microbials. Other less studied interventions, such as vaccinating cattle for S. Dublin and bacteriophage therapies, show promise but to date have had limited effects with decreasing Salmonella levels in cattle feces. No single intervention to eliminate Salmonella shedding in cattle feces was identified in this review. Therefore, a more effective strategy may involve a combination of these interventions. Further research with vaccinations and bacteriophage therapies may be warranted to find a solution for decreasing S. Dublin shedding in cattle and, ultimately, foodborne infections in humans.

Causes, Economic Effects and Preventive Strategies of Cholera Outbreaks in Africa

( E. D. Baher )

Cholera is an acute infection of the intestine caused by food or water consumption contaminated with the toxigenic bacterium Vibrio cholerae serogroup O1 or O139. Cholera outbreaks - characterized by massive disease burden, high Case Fatality Ratios, and ongoing endemicity - continue to be a public health issue in Africa. The objectives of this study were to identify the most common sources and causative agents of cholera infection and their linkage to food safety; review the direct and indirect cost of cholera’s economic burden; provide prevention strategies; make recommendations to improve the prevention and control strategies of cholera outbreaks. To meet these aims, a thematic search for original research of causes, economic effects, and prevention strategies of cholera outbreaks was conducted via the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (aka, PRISMA) process. Analyses of the results revealed that the V. cholerae O1 type El-Tor was implicated in almost all cholera cases throughout Africa and should be considered the primary causative agent of the cholera outbreaks. Based on these findings, several recommendations were made to combat and prevent further cholera outbreaks in Africa.


A Literature Review of Salmonella Growth and Survival in Low Water Activity Foods

( M. A. Cahill )

Foods manufactured with water activities below 0.85 have been shown to prevent the production of many pathogens. However, there is still a risk for foodborne illness with certain foods that are considered to have low water activity. The risk for contamination is independent of the processing phase and, therefore, can be present in the finished product if a pathogen is in the raw material. This literature review specifically addresses the survivability of Salmonella in spices, powders, flours, peanut butter and dried fruits and meats; all considered to be low water activity foods. Salmonella’s ability to adapt to, and resist destruction in, typical manufacturing environments has made this pathogen an issue for many dry food processing manufacturers. In addition, the survival of Salmonella under low water activity is neither serotype nor food dependent. Risk based process controls must be validated and applied consistently from receipt of raw materials to shipment of finished product since Salmonella contamination of the food can occur at any point. Although foods with low water activity are typically not good hosts for most bacteria associated with foodborne illnesses, Salmonella’s ability to survive through adaptation makes it a special concern for dry food processing manufacturers.