Validation of pathogen destruction during manufacture of a meat-based potato snack (Chiparoo)

A Chiparoo is a comminuted rabbit and sweet potato dehydrated snack chip manufactured using a process suitable for underdeveloped regions of the world. The purpose of this study was to evaluate the ability of the Chiparoo manufacturing process to adequately deliver 5 log reductions in Listeria monocytogenes, Escherichia coli O157:H7, Salmonella typhimurium, and Staphylococcus aureus per gram of food product. These four pathogens were inoculated into regular (pH∼6.0) and lime juice added (pH∼5.0) formulations of rabbit and sweet potato Chiparoos. They were inoculated as a cocktail of four microorganisms at concentrations of approximately 10⁶/g of each pathogen. Individual inoculations of each pathogen at the same concentration (10⁶/g) were also prepared. After inoculation, the product was held for 5 h at 37C, to simulate the maximum hold time in a sub-Saharan Africa manufacturing facility, then dehydrated at 55C (+/- 5C) for 9 h. Samples of the product were taken during the hold and dehydration steps, decimally diluted and plated on the appropriate enumeration medium. The regular formulation (pH∼6.0) did not achieve the required 5 log reduction of each of the four pathogens, while the lime juice added formulation (pH∼5.0) achieved the desired minimum 5 log reduction for each of the four foodborne pathogens tested.