Development of a PCR protocol to detect patulin producing moulds in food products

Patulin is a secondary toxic metabolite with important health effects. Several mould species of Penicillium and Aspergillus genera associated with patulin production have been detected in food products. Thus, specific and sensitive methods to detect patulin producing moulds are needed. The aim of this work was to develop a polymerase chain reaction (PCR) method to detect patulin producing moulds in food. 34 patulin producing and 30 non-producing strains belonging to the main species usually reported in food products were used. Patulin production was firstly evaluated by mycellar electrokinetic capillary electrophoresis and high-pressure liquid chromatography-mass spectrometry in all tested strains. Biosynthesis was also used to develop PCR primers derived from the genes involved in patulin. By means of a primer pair based on the isoepoxydon dehydrogenase (idh) gene, a 496-bp amplicon was specifically detected in all the mould strains previously confirmed as patulin producing, regardless of their genus and species. With the developed method it was possible to detect down to 0.5 ng of pure DNA from producing strains and from 1.8 × 102 to 2.7 × 103 conidia g−1 in artificially inoculated foods. No relevant PCR inhibition due to food matrices was observed. The PCR protocol developed could be considered as an appropriate tool to detect patulin producing moulds in food products.

► Development of PCR based on idh gene to detect patulin producing moulds. ► The PCR detects specifically producing moulds regardless genus and species. ► The developed method shows high sensitivity detecting 102-103 conidia g−1 in foods. ► No relevant PCR inhibition due to food matrices was observed. ► The developed PCR should be used to monitor patulin producing moulds in foods.