Publication Type

Journal Article

Journal Name

International Journal of Tropical Insect Science

Publication Date

1-1-2025

Abstract

Rearing edible insects on different agricultural waste streams predisposes them to microbial contamination which poses health risks to consumers. In this study, the effect of pre-harvest starvation on microbial load, weight loss and proximate composition of the edible field cricket (Gryllus bimaculatus) and the desert locust (Schistocerca gregaria) were investigated, with a view to evaluating this practice as a safety measure against pathogenic microbes in farmed edible insects. The allocated starvation times were 0 h, 12 h, 24 h, 36 h and 48 h. The weights of the starved insects were monitored and the weight loss computed. Live starved insects were cultured on standard media for detection of Salmonella and Campylobacter pathogens; and for microbial quantification. Proximate composition of the starved insects was determined using standard chemical analyses. The weights of both species of starved insects reduced by 20–45%; and their dry matter, crude protein, crude fat, crude ash and crude fibre contents were also significantly reduced by the different durations of starvation. The total viable count (TVC) and yeast and mould count (YMC) reduced significantly from unstarved insects, in both G. bimaculatus and S. gregaria, reaching their minima after 12 h and 24 h of starvation, respectively. However, the bacterial and fungal loads in both insect species increased with further starvation to levels above or below prestarvation points, respectively. Irrespective of the starvation period, all samples of G. bimaculatus and S. gregaria tested positive for Salmonella, but negative for Campylobacter species. Clearly, even though the pre-harvest starvation significantly reduced the microbial loads in the edible insects, there is a need for a benefit–cost analysis of the safety enhancement of the practice vis a vis the losses in weight and the nutritional composition of the insects.

Keywords

Bacterial loads, Food safety, Fungal loads, Mass rearing, Nutrtional composition

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