Upcycling of mycotoxin contaminated grains to food: The Yellow Mealworm (Tenebrio molitor), a safe utilizer of trichothecene-contaminated oats?

Within the European Union (EU), edible insects need to be approved as “Novel Food” according to Regulation (EU) 2015/2283 and must comply with the requirements of European food law with regard to microbiological and chemical food safety. Substrates used for feeding insects are susceptible to the growth of Fusarium spp. and consequently to contamination with trichothecene mycotoxins. Therefore, the current study aimed to investigate the influence of T-2 and HT-2 toxin on the larval life cycle of yellow mealworm (Tenebrio molitor (L.)) and to study the transfer of T-2, HT-2, T-2 triol and T-2 tetraol in the larvae. In a 4-week feeding study, T. molitor larvae were kept either on naturally (oat flakes moulded with Fusarium sporotrichioides) or artificially contaminated oat flakes, each at two levels (approximately 100 and 250 µg/kg total T-2 and HT-2). Weight gain and survival rates were monitored, and mycotoxins in the feeding substrates, larvae, and residues were determined using LC-MS/MS. Larval development varied between the diets and was 44 % higher for larvae fed artificially contaminated diets. However, the artificially contaminated diets had a 16 % lower survival rate. No trichothecenes were detected in the surviving larvae after harvest, but T-2 and HT-2 were found both in the dead larvae and in the residues of naturally and artificially contaminated diets

Distribution of T-2 toxin and HT-2 toxin during experimental feeding of yellow mealworm (Tenebrio molitor)

Within the European Union (EU), edible insects need to be approved as “Novel Food” according to Regulation (EU) 2015/2283 and must comply with the requirements of European food law with regard to microbiological and chemical food safety. Substrates used for feeding insects are susceptible to the growth of Fusarium spp. and consequently to contamination with trichothecene mycotoxins. Therefore, the current study aimed to investigate the influence of T-2 and HT-2 toxins on the larval life cycle of yellow mealworm (Tenebrio molitor (L.)) and to study the transfer of T-2, HT-2, T-2 triol and T-2 tetraol in the larvae. In a 4-week feeding study, T. molitor larvae were kept either on naturally (oat flakes moulded with Fusarium sporotrichioides) or artificially contaminated oat flakes, each at two levels (approximately 100 and 250 μg/kg total T-2 and HT-2). Weight gain and survival rates were monitored, and mycotoxins in the feeding substrates, larvae and residues were determined using LC-MS/MS. Larval development varied between the diets and was 44% higher for larvae fed artificially contaminated diets. However, the artificially contaminated diets had a 16% lower survival rate. No trichothecenes were detected in the surviving larvae after harvest, but T-2 and HT-2 were found both in the dead larvae and in the residues of naturally and artificially contaminated diets

A multidrug-resistant Salmonella enterica Typhimurium DT104 complex lineage circulating among humans and cattle in the USA lost the ability to produce pertussis-like toxin ArtAB

Salmonella enterica subsp. enterica serotype Typhimurium definitive type 104 (DT104) can infect both humans and animals and is often multidrug-resistant (MDR). Previous studies have indicated that, unlike most S. Typhimurium, the overwhelming majority of DT104 strains produce pertussis-like toxin ArtAB via prophage-encoded genes artAB. However, DT104 that lack artAB have been described on occasion. Here, we identify an MDR DT104 complex lineage circulating among humans and cattle in the USA, which lacks artAB (i.e. the ‘U.S. artAB-negative major clade’; n=42 genomes). Unlike most other bovine- and human-associated DT104 complex strains from the USA (n=230 total genomes), which harbour artAB on prophage Gifsy-1 (n=177), members of the U.S. artAB-negative major clade lack Gifsy-1, as well as anti-inflammatory effector gogB. The U.S. artAB-negative major clade encompasses human- and cattle-associated strains isolated from ≥11 USA states over a 20-year period. The clade was predicted to have lost artAB, Gifsy-1 and gogB circa 1985–1987 (95 % highest posterior density interval 1979.0–1992.1). When compared to DT104 genomes from other regions of the world (n=752 total genomes), several additional, sporadic artAB, Gifsy-1 and/or gogB loss events among clades encompassing five or fewer genomes were observed. Using phenotypic assays that simulate conditions encountered during human and/or bovine digestion, members of the U.S. artAB-negative major clade did not differ from closely related Gifsy-1/artAB/gogB-harbouring U.S. DT104 complex strains (ANOVA raw P>0.05); thus, future research is needed to elucidate the roles that artAB, gogB and Gifsy-1 play in DT104 virulence in humans and animals