Effects of infestations of the storage mite Tyrophagus putrescentiae (Acaridae) on the presence of fungal species and mycotoxin production in stored products

Abstract

The storage mite Tyrophagus putrescentiae (Schrank) (Acari: Acaridae) is one of the most important pests of stored foods (cheese, corn, oats, wheat, soy etc.), and is found in heavy infestations. Mites can infest food that are stored under unsatisfactory sanitary conditions, which may also provide conditions for fungi growth, which indicates mite-fungus association. However, little is known about the influence of T. putrescentiae on mycotoxins production under different stored products over time. The main objective of the present study was to identify the fungal species present in oats, corn, and wheat flour associated with T. putrescentiae infestations, and evaluate mycotoxin production before and after six months storage with these infestations. Wheat, corn and oat grain samples were compared, and each crop was stored in six containers infested by T. putrescentiae. Three remaining containers were stored under the same temperature and humidity conditions without introducing the mites, which worked as control. We obtained 55 fungi isolates, and the majority were identified with 99% or 100% of identity and ≥97% of coverage with type strains of each fungal species. Mycotoxin concentrations analyzed from corn flour stored for six months decreased with and without T. putrescentiae (p < 0.05). Regarding mycotoxin concentration with T. putrescentiae, aflatoxin increased in oats (p < 0.05) while zearalenone decreased in wheat (p < 0.05). Our findings proved that T. putrescentiae could significantly induce mycotoxin production in stored products evaluated for six months.