Evaluation of Tenebrio molitor larvae as an alternative food source

Abstract

Edible insects have gained an increasing interest as a food product in recent years. They may represent an alternative source of protein and micronutrients compared to conventional meat sources. Thus the objective of this work was to determine the nutritional value as well as the chemical and microbiological contamination for a better evaluation of the risk/benefit of yellow mealworm larvae consumption. These larvae have a nutritional value (10.4% of fat and 13.7% of protein) similar to conventional meat sources. Their main fatty acids were oleic (37.8%) and linoleic (33.2%). The results showed these larvae fulfill the requirements for essential amino acids (all were above 100% of the daily contribution), with the exception of lysine. Our findings also showed that T. monitor larvae are an excellent source of minerals like phosphorus, magnesium and zinc (114%, 109 to 128% and 117% above RDI). In spite of having a low contribution of potassium and iron (16–17% and 20% of RDI), the lower sodium content is an advantage in terms of human health since high intake increases blood pressure. Mercury and lead values were below the detection limit and cadmium level was 0.10 mg/kg. Yellow mealworm larvae had high bacterial loads but no pathogenic bacteria were detected. Starvation for eight days at 5 °C reduced the total counts of all microorganisms, specially yeasts and total mesophilic anaerobic spore-forming bacteria.