Effect of Potassium Sorbate and Other Treatments on the Microbial Content and Keeping Quality of a Restaurant-Type Mexican Hot Sauce

Abstract

Spoiled and unspoiled restaurant-made Mexican hot sauces were examined for presence of pathogenic and spoilage microorganisms. Studies to determine whether microorganisms isolated from the sauce could grow and cause spoilage were also carried out. The effects of potassium sorbate at various levels (0, 0.02, 0.03, 0.05, 0.1 and 0.2%) on the keeping quality of the sauce were also determined. Spoiled sauce had microbial counts 4 log-cycles higher than the unspoiled sauce. Bacteria were either very few or absent in all the samples and were unable to grow when reinoculated. The pH of the sauce was below 4.5. Yeasts increased after 10 d of incubation and were the main organisms that caused the spoilage. Potassium sorbate at .05% was inhibitory to yeasts in both original and inoculated sauces. Levels of 0.02 and 0.03% were only fungistatic. Benzoic acid at 0.05% was also inhibitory, while heating at 80°C for 10 min did not extend shelf life appreciably, and acidification to pH 3.5 increased shelf life only slightly.