engleski

Distribution of mycotoxigenic moulds isolated from traditional meat products in different Croatian climate regions and their ability to produce mycotoxins

Mycobiota grow on the surface of traditional meat products (TMP), which gives them a specific texture, flavour, and colour. However, in unfavourable conditions moulds produce mycotoxins if they possess the genes involved in their biosynthesis. The most toxic mycotoxins in TMP products are aflatoxin B1 (AFB) and ochratoxin A (OTA), while the incidence of cyclopiazonic (CPA) acid and citrinin (CIT) on meat products has until now not been researched. The aim of this study was to identify moulds species capable of producing the studied mycotoxins by proving the existence of the genes involved in their biosynthesis. This study analysed 250 TMPs sampled during 2020 and 2021 from five different climate regions of the Republic of Croatia (eastern, northern, central, western, and southern). The tested genes involved in the AFB1 biosynthesis are: aflD encoding norsolorinic acid reductase, aflM encoding versicolorin A dehydrogenase and aflP encoding sterigmatocystin-Omethyltransferase, OTA otanpsPN encoding OTA nonribosomal peptide synthetase and otapks encoding OTA polyketide synthase ; CIT pksCT gene encoding CIT polyketide synthase, and CPA dmaT encoding dimethylalyl tryptophan synthase. A total of 181 isolates of 9 different potentially toxic mould species were identified, out of which 50 % of the identified isolates of potential AFB1 producers (A. flavus), 58 % isolates of potential OTA producers (P. nordicum, A. niger, A. westerdijkiae, A. welwitschie, A. tubingensis), 71 % of isolates of potential CIT producers (P. citrinum) and 48 % of isolates of potential CPA producers (P. commune, A. flavus, P. polonicum) all had the investigative genes involved in mycotoxin biosynthesis. In 21 % of the samples contaminated with some of the detected mycotoxins (OTA or CPA), their producers (P. nordicum, P.commune and A. flavus) were determined, while contamination of the samples in which the producers were not identified can be explained either by some previous contamination of TMP ingredients or by the possibility that the producers had been covered and became overgrown by other mould species at the end of the ripening stage and therefore avoided detection. The incidence of the number and identified mould species has been linked to data on the weather conditions relating to the various Croatian regions. Therefore, the western region had the highest number of isolated toxic mould species, followed by the northern region, while the greatest diversity of toxic mould species was in the western and eastern regions.

Aspergillus ; dry-cured meat ; mycotoxin biosynthesis ; Penicillium ; regional weather conditions

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