Distribution of aflatoxin M1 during production of sheep and goat cheeses

The occurrence of Aflatoxin M1 (AFM1) in milk results from ingestion of contaminated feed with Aflatoxin B1 by dairy animals, its conversion into AFM1, and secretion in milk. The objective of this work was to investigate AFM1 fate along goat and sheep cheese production. Cheese production was carried out using spiked milk (levels between 0.08 and 0.10 ?g/L). Samples were collected throughout the production and analyzed by immunoaffinity cleanup and chromatography. Higher concentration of AFM1 was always observed in curd rather than in whey; with a mean enrichment factor of 1.8. A strong and positive correlation was established between casein content and AFM1 percentage in curd. Throughout production, a significant increase in AFM1 concentration on a wet basis was observed. In turn, on a dry basis, there was no statistically significant reduction during ripening. These observations are justified by the loss of cheese moisture and the absence of AFM1 degradation.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit. PR is grateful to FCT and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2019).