OTA AND NON-OTA-PRODUCING MOULDS IN DRY-CURED HAM MODEL

APPLICATION OF NEAR-INFRARED SPECTROSCOPY IN THE DIFFERENTIATION OF OTA AND NON-OTA-PRODUCING MOULDS IN DRY-CURED HAM MODEL

E. Cebrián1, A. González-Mohino2, I. Martín1, F. Núñez1, M. Rodríguez1, S. Grassi3

1Food Hygiene and Safety, Meat and Meat Products Research Institute (IProCar), Faculty of Veterinary Science, University of Extremadura. Cáceres, Spain; 2 Food Technology, Meat and Meat Products Research Institute (IProCar), Faculty of Veterinary Science, University of Extremadura. Cáceres, Spain 3Department of Food, Environmental, and Nutritional Sciences (DeFENS), Università degli Studi di Milano, Milan, Italy.

evcebrianc@unex.es

Moulds commonly grow on the surface of dry-cured meat products. Some of them are able of producing ochratoxin A (OTA), posing a food safety concern. Therefore, the detection of the OTAproducing moulds before OTA synthesis is convenient. To the aim, this work evaluated the potential of near infrared spectroscopy (NIRS) as a rapid and non-destructive method, for the discrimination between OTA-producing (P. nordicum, P. verrucosum and A. westerdijkiae) and non-producing mould (P. commune and P. polonicum) species on dry-cured ham-based substrate. Cultures were incubated at 12 and 25 ºC for 32 days. Four NIRS measurements (5, 13, 25 and 32 days after inoculation) were taken in quintuplicate at five locations for each plate at the two study temperatures. The collected spectra were used to develop Support Vector Machines–Discriminant Analysis (SVMDA) models by a hierarchical approach. First a SVM-DA model was developed to classify into OTA and non-OTA producing moulds. Then, two models were tested to discriminate species among the ochratoxigenic and non-ochratoxigenic moulds. The SVM-DA model could discriminate OTA and non-OTA producers with 85% of sensitivity and 86% of specificity in prediction. The following models were able to differentiate among non-ochratoxigenic species (95% of sensitivity and specificity) and among OTA-producing species (69% of sensitivity and 90% of specificity). This preliminary in vitro study is promising and the use of a portable NIRS system could be a rapid and non-destructive tool to monitor the presence of ochratoxigenic moulds on dry-cured ham surfaces. Therefore, further assays have been started on dry-cured ham to test its effectiveness.

Acknowledgements. This work has been financed by the Spanish Ministry of Science and Innovation, Government of Extremadura and FEDER (PID2019-104260GB-100, GR18056). E. Cebrián is recipient of a pre-doctoral fellowship from the Spanish Ministry of Science and Innovation (PRE2020-093605).

Keywords: toxigenic moulds; ochratoxin A (OTA); near-infrared spectroscopy (NIRS); portable device

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