Monitoring Aflatoxin M1 levels in ewe's and goat's milk in Thessaly, Greece; potential risk factors under organic and conventional production schemes

Consumers prefer organic food as they consider it healthier and safer. Since Aflatoxin M1 (AFM1) in milk and dairy is considered as hazard to human health this study aimed to assess the level of AFM1 contamination in ewes and goats raw milk in Greece, identify possible risk factors and compare organic and conventional milk. Thirty-nine organic and 39 conventional farms participated in this study and 243 samples were collected, during a lactation period (December–July). A standardized questionnaire and a sampling protocol were completed for all farms and samples, including information for the farming system. Samples were screened for AFM1 with ELISA and confirmed with HPLC. Analytical results were statistically analysed as to explore any associations with the questionnaire data for possible risk factors. Out of 234 samples analysed, in 191 (81.6%) samples AFM1 was not detected, while 4 (1.7%) were found above the EU maximum tolerable limit of 50 ng kg−1. There was no conventional samples found over the maximum limit for AFM1 (0/117), while 4/117 (3.4%) organic samples exceeded 50 ng kg−1 [no statistically significant difference (p-value = 0.122)]. It was found more possible for organic farms to present AFM1 contamination in comparison to conventional [no statistically significant difference (RR 1.2, 95%CI 0.71–2.02, p-value = 0.492)]. Among several potential risk factors investigated for AFM1 milk contamination, the use of warehouse for feed storage (OR 2.69, 95%CI 1.25–5.79), winter season (OR 2.58, 95%CI 1.07–6.24) and feeding field pea (OR 4.17, 95%CI 1.41–12.32) were identified as statistically significant. Organic milk samples were not found less contaminated with AFM1, but even higher contamination is possible, in comparison to conventional milk. The complex of the associated risk factors in AFM1 contamination found (winter season, feed storage practises and feeding pea), indicates that these should be associated when assessing AFM1 contamination risk in milk and that constant monitoring and increased farmer's awareness is needed. •AFM1 contamination levels in raw milk in Greece are relatively low (18.4%).•Organic milk is not less contaminated with AFM1 in comparison to conventional.•Organic milk is possibly even more contaminated with AFM1 compared to conventional.•Possible risk factors for AFM1 contamination could be season, feed storage and feed type.•Constant monitoring and increased awareness is needed to control AFM1 levels.