THE OCCURRENCE, GROWTH AND CONTROL OF PATHOGENS IN AFRICAN FERMENTED FOODS

Abstract

Fermented foods have many advantageous attributes such as improved nutritional value and safety against bacterial pathogens. These foods are also important for weaning purposes and hence play a role in protecting infants against foodborne diseases. However, pathogens have been isolated from some fermented foods and challenge tests have shown the possibility of pathogens to survive and grow in some fermented foods. Post processing contamination is often cited as the major cause of food poisoning. Fermented foods with a pH value below 4 are usually safe as most pathogens are unable to survive under these conditions. However, some pathogens such as Escherichia coli O157:H7 are reported to develop acid tolerance. This is a particular problem for fermented sausages. However, there is very little information on the occurrence and growth of pathogens in African fermented foods. Most work on African fermented foods has focused on the isolation and identification of the desirable microorganisms involved in the fermentation process. Some authors have now started focusing on the possibility of some pathogens to survive and grow in some of the fermented foods. This review highlights some of the cases where pathogens have been detected in fermented foods, or have been shown to survive and grow in such foods. The most commonly encountered pathogens in African fermented foods include Bacillus cereus, E. coli, Salmonella sp., Staphylococcus aureus, Vibrio cholerae, Aeromonas, Klebsiella, Campylobacter and Shigella sp. The approaches that can be used to minimise the risk of foodborne diseases through consumption of fermented foods include improved hygiene, use of starter cultures, use of protective cultures and the use of a combination of factors that inhibit the growth of microorganisms (multiple hurdles). The use of concepts such as Hazard Analysis Critical Control (HACCP) system is still problematic at household level. However, this approach has been suggested for some African fermented foods such as kenkey (Ghana). This is thought to help in channelling resources to steps that provide effective protection.


Key Words: fermented foods, pathogens, weaning foods, bacteriocins


AJFAND Vol.4(1) 2004: