DEVELOPMENT OF LOOP-MEDIATED ISOTHERMAL AMPLIFICATION (LAMP) ASSAY FOR RAPID DETECTION OF OCHRATOXIN A-PRODUCING ASPERGILLUSWESTERDIJKIAE STRAINS ON CACIOCAVALLO CHEESE

Background and Aims Aspergillus westerdijkiae , a fungal species that produces the harmful mycotoxin ochratoxin A (OTA), is frequently isolated from aged foods, including dry-cured meats and cheese. Mycotoxin occurrence in food is worldwide regulated, because of the toxic effects that these fungal secondary metabolites couldhave on consumers' health. However, in dairy products, only the carcinogenic aflatoxin M1 is regulated, even thoug also OTA has been often detected insuch products. Monitoring and early detection of OTA-producing fungi in foods are among the most effective strategies to manage OTA contaminationand to prevent human consumption of OTA-contaminated food products. DNA-based diagnostic tools for rapid, simple, and cost-effective detection of toxigenic food-borne fungi have been developed and are effective. Loop-mediated isothermal amplification (LAMP) is one of these innovative methods, suitable for direct application “on-site” in food chain production. Methods In this study, a LAMP assay was developed for the specific detection of toxigenic Aspergillus westerdijkiae on Caciocavallo cheese surface. The assay isbased on the detection of bZIP gene, a key gene in the biosynthesis of OTA and has been combined with an in-tube colorimetric detection method for anaked eye evaluation of positive and negative samples. Results Results showed that the assay is able to selectively detect the DNA of A. westerdijkiae at a very low concentrations (10fg/reaction). Conclusions The developed assay represents an alternative rapid, specific and sensitive DNA-based method suitable for application directly “on-site”, notably in theaging step of cheese production.