Review of the Literature


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. 

Analysis of Current Research and Identification of Known Vectors for C. cayetanensis and Vectors for Contamination by C. cayetanensis

( E. Fernandes )

Outbreaks of Cyclospora cayetanensis (C. cayetanensis) have occurred in the USA nearly every year since 2000. Although these outbreaks have historically been connected to imported produce or international travel, the 2018 spike in cyclosporiasis illnesses was connected to domestically grown produce. Foreign research on the public health risk of domestic C. cayetanensis, while informative, did not identify all vectors pertaining to sources of infection in the USA. Therefore, the objective of this review paper was to identify the root causes of the transmission of this protozoan pathogen to humans. Twenty-six papers spanning the past 12 years were analyzed along with product testing results from the FDA between 2018 and 2019, and epidemiological data from the CDC on the two domestic (USA) C. cayetanensis outbreaks implicated in 2018. This review found that public health risk associated with domestic sources of infection by C. cayetanensis was difficult to quantify due to insufficient research. Future studies should focus on transmission routes in the domestic produce supply chain, starting with growing regions where previously contaminated product was sourced.