Occurrence of aerobic bacterial endospores in dried dairy ingredients

Abstract

The present study investigated types of bacterial endospores in powdered dairy ingredients. For enumeration, the samples were heat‐treated at 80°C/12 min for regular spore type, 100°C/30 min for high‐heat‐resistant spores (HHRS), and 106°C/30 min for specially thermoresistant spores (STS), followed by incubation for 24 h at 37°C (for mesophiles) and 55°C (for thermophiles). Of the three types, the regular spore type (80°C/12 min) was observed to be the most prominent endospore type, and Bacillus licheniformis as the predominant bacterial species in the tested dairy ingredients. This study would be helpful to utilise dry ingredients based on the potential activation of endospores during the product manufacturing processes.