Assessment of contamination of coffee, cocoa and cocoa products, marketed in Russian, with mold fungi — potential producers of mycotoxins

Introduction. Beverages and products based on coffee and cocoa are included in the basic products in the consumer basket. The mycoflora of coffee and cocoa raw materials may contain mycotoxigenic molds from tropical and subtropical regions. This causes the hazard of contamination of finished products with mycotoxins (MT) and the need for in-depth study of potential MT producers.

Materials and methods. Microbial contamination of samples of coffee, cocoa beans and cocoa products (retail chain of the Moscow region) was studied by cultural methods. Toxin formation of single-spore isolates (SSI) of molds under in vitro conditions was determined in the culture substrate by the UHPLC-MS/MS method in the multidetection format (18 MT).

Results. All samples examined were characterized by low microbial contamination. The surface mycoflora was dominated by Aspergillus species of the section Nigri. The contamination of the internal microflora of green coffee beans with molds was studied. Infection was 70–100%, mainly Aspergillus spp.; 48 SSI were isolated: 60% — Aspergillus species of the Nigri section, 12.5% — Aspergillus of the Flavi section and 27% — Aspergillus spp. Under in vitro conditions, the formation of dangerous MTs was detected in 50% of SSI, the maximum amount reached (mg/kg of substrate): fumonisin B2 — 24.0 (A.niger), ochratoxin A — 518.0 (Aspergillus section Nigri), aflatoxin B1 — 27.9 and aflatoxin B2 — 1.44 (A.flavus), sterigmatocystin — more than 380.0 (A.parasiticus).

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. Aspergillus spp. were shown to dominate in the surface mycoflora of finished food products and the internal mycoflora of unprocessed raw materials. There has been established the ability of strains of Aspergillus sp. from the internal microflora of green coffee to the formation of high levels of hazardous MTs. The presence of potential risk of MT contamination of these types of food products necessitates monitoring their contamination with MT-producing molds. The presence of toxigenic activity in molds isolated from green coffee has been shown in Russia for the first time.

Contribution:

Minaeva L.P. — concept and design of the study, collection and processing of the results of toxin formation and 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 the results of phenotypic identification of molds;

Markova Yu.M., Polyanina A.S., Bykova I.B., Stetsenko V.V., Efimochkina N.R. — collection and processing of material of microbiological studies;

Chalyy Z.A. — collection and processing of material UHPLC-MS/MS research results;

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.

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

Acknowledgement. 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 30, 2021 / Accepted: April 12, 2022 / Published: April 30, 2022