Nature of the inactivation by high hydrostatic pressure of natural contaminating microorganisms and inoculated Salmonella Typhimurium and E. coli O157:H7 on insect protein-based gel particles

Cuauhtemoc Marin,Diana Ibañez,Gabriela Rios-Corripio,Jose Angel Guerrero,Dolores Rodrigo,Antonio Martinez

doi:10.1016/j.lwt.2020.109948

Abstract

This work studies and models microbial inactivation by high hydrostatic pressure applied to insect protein (Acheta domesticus) enriched gels. The target microbial groups and pathogens studied were total aerobic mesophilic (TAM) bacteria, molds and yeasts (M&Y), Salmonella Typhimurium and Escherichia coli O157:H7. Results indicated that high hydrostatic pressure reduced the microbial load of both, the natural contaminating microorganisms (TAM and M&Y) and the intentionally inoculated pathogenic microorganisms. However, inactivation of the initial microbial load was lower than 5-log reductions. Kinetic inactivation parameters were deduced by using the Weibull distribution function which presented high goodness of fit. Kinetic parameters of the model showed that the most resistant microbial group was total aerobic mesophilic bacteria, followed by E. coli O157:H7, mold and yeast and Salmonella with kinetic parameters of 2.21, 1.58, 1.27, and 0.17 (min × mL/CFU) at 350 MPa, respectively. Regarding the pathogenic microorganisms inoculated in insect protein gels, E. coli O157:H7 may be a good candidate Gram negative target microorganism for high hydrostatic pressure process development, because it usually contaminates these products and was the one with the highest baro-resistance. These reasons support that high-pressure treatments for this type of food should be designed considering this microorganism as a target.

Highlights

Insects currently constitute part of the diet of approximately 2000 million people and their consumption is being considered as a strategy to combat famine in countries with protein deficits (FAO 2013)
To develop suitable high hydrostatic pressure (HHP) processes for a new food based on gel particles containing insect protein, a kinetic study was carried out considering different groups of microorganisms at different treatment pressures
The results for inactivation of total aerobic mesophilic (TAM) bacteria, and of yeasts and molds (Y&M) as natural contaminating microorganisms in protein gel particle samples treated using various pressures and times are shown in figures 1 and 2, respectively

Summary

Introduction

Insects currently constitute part of the diet of approximately 2000 million people and their consumption is being considered as a strategy to combat famine in countries with protein deficits (FAO 2013). With the January adoption of the Novel Foods Regulation (EU) 2283/2015, insects and their derivatives are considered Novel Foods and are subject to the corresponding approval procedures. This represents a significant change from previous legislation by opening the door to insect consumption. One of the insects under consideration for the production of new high-protein foods for human consumption is Acheta domesticus (common cricket). It could partially or totally replace the protein from these animal sources in foodstuffs

Methods

Results

Conclusion