Quantitative characterization of microbial load in wild-harvested edible insects of Nagaland, India

Abstract

Aim: To analyze the microbial load in raw and roasted insects in an attempt to determine the efficiency of heat treatment in removing the microbial load. Methodology: Fresh as well as roasted (over low flame for 15 min) insect samples were used to determine the microbial contaminants. Crushed insect samples were suspended in sterile half-strength nutrient broth solution and were further serially diluted 10-fold (up to 10-10) in isotonic half-strength nutrient broth solution. The total number of aerobic mesophilic microorganisms were determined on plate count agar and expressed as log Cfu g-1. Results: Differences in the number of microbial colonies were observed in fresh and roasted samples. The microbial load ranged from 6.30-8.75 log Cfu g-1 and showed that the highest microbial colonies were present in the fresh samples. The average log Cfu g-1 in fresh insect samples (7.57±0.87) was significantly higher (P<0.05) as compared to roasted samples (7.07±0.76). Interpretation: Edible insects require proper processing before consumption to reduce microbial contamination and further study is needed to identify specific microbes/food pathogens to develop microbial quality and parameters to ensure consumer safety. Key words: Alternative food, Edible insects, Food safety, Microbial contaminants, Traditional foods