Contamination of fruit and berry products with mycotoxigenic mold fungi

Introduction. To assess the risk of exposure to mycotoxins contaminating fruit and berry products, it is necessary, as a mandatory step, to identify mold fungi growing on fruits, determine their levels and conditions that contribute to the formation of their toxigenic potential. This is relevant in relation to the group of such food products as fresh berries and fruits until now little studied in this aspect.

Materials and methods. Contamination of berries and fruits with mold fungi was studied by cultural methods with micro- and macromorphological identification of species. Mycotoxins (MT) were determined by UHPLC-MS/MS in multi-detection format (28 MT).

Results. In eighty seven samples of berries and fruits without signs of deterioration, there were studied the species composition of mycoflora, its quantitative levels and the content of MT. In most samples (80%), the mold content and total microbial contamination did not exceed the established standard values for similar processed fruit and berry products (quick frozen). The samples of strawberry were the most contaminated, the least — plum and dogwood. Analysis of the taxonomic composition of the epiphytic mycoflora showed the dominance of fungi of the genus Alternaria (gooseberry, currant and plum); Aspergillus sp. (Strawberry); mushrooms of the order Mucorales (raspberries). However, during chemical analysis, dangerous fusariotoxins were found in samples of strawberries, red currants and plums, the producers of which are Fusarium sp. were noted not to be found in the surface microflora. In general, dangerous MTs (fusariotoxins, patulin, aflatoxins, ochratoxin B) and emergent MTs (alternaritoxins, bovericin, enniatines, etc.) were found in berries and fruits, the levels of which were below the levels normalized in food products. A comparison was made of the levels of microbial contamination in fresh berries and fruits and those subjected to technological processing (convection drying and shock freezing). It is shown that the microbiological purity of products with such processing methods is mainly ensured by the quality of food raw materials, since the conditions of convection drying and shock freezing do not lead to microflora inactivation.

Limitations. Within the framework of the study, the species affiliation of MSIs was carried out by mycological methods without the use of PCR analysis, which will be the subject of further research.

Conclusion. The absence of visible spoilage of berries and fruits has been shown to no mean the absence of MT in them, and mycotoxigenic molds may not be detected in the mycoflora of fruits. Contamination of fruit and berry products with a wide range of regulated and emerging MTs was revealed, which confirms the need for an in-depth study of the contamination of these types of products with mycotoxins that are hazardous to human health, with the aim of subsequent assessment of the risk of their entry into the human body.

Compliance with ethical standards. This study does not require the conclusion of a biomedical ethics committee or other documents.

Contribution:
Minaeva L.P. — concept and design of the study, collection and processing of materials of microbiological studies and of the results of phenotypic identification of molds, writing and editing of the manuscript, responsibility for the integrity of all parts of the article;
Evsjukova A.D. — collection and processing of materials of microbiological studies and of the results of phenotypic identification of molds;
Koltsov V.А. — collection and provision of samples for research, technological processing of samples;
Zhidekhina T.V. — development of the concept of selection of varieties of fruits and berries obtained using modern resource-saving agricultural technologies, sampling of fruits and berries;
Sedova I.B., Chalyy Z.A. — collection and processing of material UHPLC-MS/MS research results;
Efimochkina N.R. — sampling, collection and processing of material of microbiological studies;
Sheveleva S.A. — agreement of the research concept, editing.
All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Acknowledgement. The authors express their gratitude to the staff of the Laboratory of Biosafety and Analysis of the Nutrimicrobiome of the Federal State Budgetary Institution of Science “Federal Research Center for Nutrition and Biotechnology”, who took part in the collection of primary material of microbiological research; Mikhail Yu. Akimov Doctor of Agricultural Sciences, Head of the Laboratory of Biochemistry and Food Technologies of the Federal State Budgetary Scientific Institution “I.V. Michurin Federal Scientific Center” for organizing the collection and transfer of research objects. 

Conflict of interest. The authors declare no conflict of interest.

Funding. The study was supported by a grant from the Russian Science Foundation (project No. 18-16-00077-P) “Emergent mycotoxins in food products of plant origin: development of methods of analysis, study of contamination, species characteristics of micromycetes-producers, development of hygienic standards”.

Received: November 7, 2022 / Accepted: March 24, 2023 / Published: April 20, 2023