Insects and mites are common inhabitants and accidental invaders of food, including durable commodities, and their presence can have both direct and indirect effects on human health. The most common direct effect is contamination of food with arthropod fragments and related contaminants, which may be allergenic or even carcinogenic. The most important indirect effect is that their presence can change the storage microenvironment, making durable products suitable for the rapid development of fungi and other microorganisms. Some of these fungi can produce toxins (e.g., aflatoxins) that endanger human health. Insects may actively or passively contribute to the spread of microorganisms, increasing product contamination, and they may host bacteria that have developed antibiotic resistance, contributing to their spread in food. Several species also may host, attract, or transmit tapeworms, predators, or parasitoids that may affect health. This review synthesizes research on these topics and suggests directions ...

Health Hazards Associated with Arthropod Infestation of Stored Products

A faunistic survey of mites was conducted in many product stores during a 6-year study period, 2000–2005, in Greece. A total of 1,073 samples were taken from 34 Greek counties. The survey was carried out on grains (wheat, maize, oat, barley), flour, bran, manufactured agricultural foodstuffs, dried fruits (figs, raisins), residues and dust, stored in varying quantities in five types of storage facilities (stores of agricultural cooperative unions, farm stores, commercial stores, flour mills and silos). Dominance-frequency analysis and redundancy analysis (RDA) were used to reveal the preferences of the collected taxa. Approximately 55% of the samples contained mites and 65 mite taxa were identified, belonging to 15 families in four orders. Six species, namely, Acarus gracilis Hughes, A. immobilis Griffiths, Caloglyphus oudemansi (Zachvatkin), Suidasia medanensis Oudemans, Tyrophagus perniciosus Zachvatkin and Kleemania plumigera (Oudemans), were new to the fauna of Greece. Five species, Tyrophagus similis Volgin, Blattisocius mali (Oudemans), Neoseiulus barkeri (Hughes), Cheyletus cacahuamilpensis Baker and Storchia robustus (Berlese), were recorded for the first time in stored products in Greece. Lepidoglyphus destructor (Schrank), Tyrophagus putrescentiae (Schrank) and Acarus siro L. were dominant or intermediate in all storage facilities examined. Cheyletus malaccensis Oudemans was the most common predatory mite. The highest percentage of infestation (65.3) was recorded in the samples from stores of agricultural cooperative unions. Residue-type materials had the highest degrees and percentages of infestation.

Mites associated with stored products in Greece

Internal bacterial communities of synanthropic mites Acarus siro, Dermatophagoides farinae, Lepidoglyphus destructor, and Tyrophagus putrescentiae (Acari: Astigmata) were analyzed by culturing and culture-independent approaches from specimens obtained from laboratory colonies. Homogenates of surface-sterilized mites were used for cultivation on non-selective agar and DNA extraction. Isolated bacteria were identified by sequencing of the 16S rRNA gene. PCR amplified 16S rRNA genes were analyzed by terminal restriction fragment length polymorphism analysis (T-RFLP) and cloning sequencing. Fluorescence in situ hybridization using universal bacterial probes was used for direct bacterial localization. T-RFLP analysis of 16S rRNA gene revealed distinct species-specific bacterial communities. The results were further confirmed by cloning and sequencing (284 clones). L. destructor and D. farinae showed more diverse communities then A. siro and T. putrescentiae. In the cultivated part of the community, the mean CFUs from four mite species ranged from 5.2 × 102 to 1.4 × 103 per mite. D. farinae had significantly higher CFUs than the other species. Bacteria were located in the digestive and reproductive tract, parenchymatical tissue, and in bacteriocytes. Among the clones, Bartonella-like bacteria occurring in A. siro and T. putresecentiae represented a distinct group related to Bartonellaceae and to Bartonella-like symbionts of ants. The clones of high similarity to Xenorhabdus cabanillasii were found in L. destructor and D. farinae, and one clone related to Photorhabdus temperata in A. siro. Members of Sphingobacteriales cloned from D. farinae and A. siro clustered with the sequences of “Candidatus Cardinium hertigii” and as a separate novel cluster.

Detection and Identification of Species-Specific Bacteria Associated with Synanthropic Mites

The pest potential of stored product mites depends on the reproduction rate that is affected by the environmental conditions. In this study we investigated the effect of temperature, ranging from 5 to 35°C, on the population growth of three important mite species, Acarus siro, Tyrophagus putrescentiae and Auleroglyphus ovatus at 85% r.h. Starting with 10 individuals the population increase of mites was observed after 3 weeks of cultivation, or after 6 weeks for those kept at low temperatures (5, 10, 12.5, and 15°C). The rate of increase was calculated for each temperature and species. The obtained data were fitted with polynomial models. The mite population growth rates increased with increasing moderate temperatures until 25°C, when rm-values were 0.179, 0.177 and 0.190 for A. siro, A. ovatus and T. putrescentiae, respectively. The lower development threshold was 10.2°C in all three species. Estimated upper temperature threshold was higher in T. putrescentiae (49°C) than in A. siro and A. ovatus (38°C). Simulation of the rate of population increase under ideal conditions, using real temperature records obtained from Czech grain stores, showed that the pest mite populations increase only during 3.5 months within a typical 9-month storage season in Central Europe. These results indicate that control of mites, be it chemical, physical or biological, is recommended during the months when allergens and pests are produced, i.e. from September to mid November and in May.

Temperature-dependent population growth of three species of stored product mites (Acari: Acaridida)

Current literature accepts 17 species in Penicillium section Sclerotiora. Several produce colonies in bright yellow to orange colours and have monoverticillate conidiophores, apart from P. herquei, P. malachiteum and P. nodositatum, which are biverticillate. The focus of this paper is to refine the concepts of the species currently accepted in the section and introduce five new species, named after the Dutch Royal family as P. vanoranjei, P. maximae, P. amaliae, P. alexiae and P. arianeae. Penicillium vanoranjei produces orange (Dutch = oranje) colonies in culture, and is named after Willem-Alexander Claus George Ferdinand, ‘Zijne Koninklijke Hoogheid de Prins van Oranje’ (translated from Dutch as: ‘His Royal Highness the Prince of Orange’) and his family, to coincide with his coronation. We review the current taxonomic positions of P. lilacinoechinulatum and P. nodositatum, both currently considered to be synonyms of P. bilaiae. Sequence data generated in this study show that both species are phylogenetically distinct. Penicillium lilacinoechinulatum is closely related to P. amaliae sp. nov., whereas P. nodositatum does not belong to Penicillium sensu stricto. All species were compared morphologically and phylogenetically, based on β-tubulin and calmodulin DNA data. A table summarising the morphological characters of all species is included, together with photomicrographs and recommended DNA markers for identification.

Five new Penicillium species in section Sclerotiora: a tribute to the Dutch Royal family

Toxigenic and allergen-producing fungi represent a serious hazard to human food and animal feed safety. Ninety-four fungal species were isolated from mite-infested samples of seeds taken from Czech seed stores. Fungi were isolated from the surface of four kinds of seeds (wheat, poppy, lettuce, and mustard) and from the gut and external surface of five species of mites (i.e., Acarus siro L., 1758, Caloglyphus rhizoglyphoides (Zachvatkin, 1973), Lepidoglyphus destructor (Schrank, 1781), Tyrophagus putrescentnae (Schrank, 1781) and Cheyletus malaccensis Oudemans 1903) separately. Multivariate analysis of fungi complex composition showed that the frequency of fungal was species significantly influenced by the kind of seed. Fungal frequencies differed between mites gut and exoskeleton surface and between the surfaces of mites and seeds. Three groups of fungal species were recognized: 1) mite surface-associated fungi: Penicillium brevicompactum, Alternaria alternata, and Aspergillus versicolor; 2) mite surface- and seed-associated fungi: Aspergillus niger, Penicillium crustosum, Penicillium aurantiogriseum, Penicillium chrysogenum, and Aspergillus flavus; and 3) seed-associated fungi: Cladosporium herbarum, Mucor dimorphosporus f. dimorphosporus, Botrytis cinerea, Penicillium griseofulvum, and Eurotium repens. Mite-carried species of microfungi are known to produce serious mycotoxins (e.g., aflatoxin B1, cyclopiazonic acid, sterigmatocystin, ochratoxin A, and nephrotoxic glycopeptides) as well as allergen producers (e.g., A. alternata and P. brevicompactum). Storage mites may play an important role in the spread of some medically hazardous micromycetes. In addition, these mite-fungi associations may heighten the risk of occurrence of mycotoxins in food and feed stuffs and cause mixed contamination by fungal and mite allergens.

https://bioone.org/journals/journal-of-economic-entomology/volume-97/issue-6/0022-0493-97.6.2144/Mites-and-Fungi-in-Heavily-Infested-Stores-in-the-Czech/10.1603/0022-0493-97.6.2144.pdf

Mites and Fungi in Heavily Infested Stores in the Czech Republic

https://web.natur.cuni.cz/ekologie/jarosik/cze/pdf/D58.pdf

E. Žd’árková

Papers

Mites and Fungi in Heavily Infested Stores in the Czech Republic

Differential natural performance of four Cheyletus predatory mite species in Czech grain stores