Use of instant controlled pressure drop technology for the preservation of edible insects' (yellow mealworm) quality: assessment of microbial inactivation

The world population is expanding, and with it, so is the need for proteins for the food and feed sectors. Conventional livestock production is correlated with negative environmental repercussions such as global warming, land degradation, and biodiversity loss. The nutritional content of edible insects is comparable to that of conventional meat, and insect farming offers various environmental advantages over livestock production, making it a favorable sustainable protein resource. However, to be placed on the market, insects should be processed, and their microbial load should be within the accepted range of the European Commission regulation (EU) 2021/882. The purpose of this research is to investigate the use of instant controlled pressure drop (DIC) technology for the microbial inactivation of yellow mealworm larvae. This innovative decontamination treatment was compared to blanching in hot water, the conventional processing method. We also investigated the impacts on enzymatic browning. Results showed that the application of rapid (20 s) DIC treatment at 0.3 MPa allowed reducing the total aerobic count and the total yeast and mold count of larvae below the thresholds authorized by the commission regulation. Pressure, temperature, and number of cycle factors were found to have significant effects on the decontamination, while the treatment time had no effect for most treatments. In regard to blanching, we were able to get the authorized load at 90 °C for 360 s. Decimal reduction times for DIC and blanching treatments were found to be 3.8 s and 67.8 s for total aerobic count, and 3 s and 57 s for total yeast and mold count, respectively. Furthermore, DIC-treated larvae showed a significant increase in juice color brightness, which could be traced back to the oxidative enzymatic inactivation of larvae, whereas there was a slight difference between blanched and untreated larvae juice colors.