[Occurrence of the mycotoxin ochratoxin a in breast milk samples from Germany]

Breast milk is the best form of nutrition early in life, yet it may contain contaminants which were ingested by mothers. Ochratoxin A (OTA) is a well-known nephrotoxin with carcinogenic properties and a frequent food contaminant. Ingested OTA is partly excreted with human milk and studies conducted in different countries have shown a wide range of OTA concentrations. The aim of this study was to assess the exposure of infants to OTA by analysing breast milk samples from 2 German areas.

Breast milk samples were obtained from 90 mothers who had signed an informed consent sheet. The previously validated analytical method (LOD=10 ng/L, LOQ=30 ng/L) involves liquid-liquid extraction and analysis by HPLC with tandem mass spectrometric detection. A preliminary risk assessment was done using the TDI approach.

More than 50% of the collected 90 milk samples contained detectable OTA levels. Overall, the average concentration in milk from -Dortmund (24.4 ± 21.1 ng/L (n=30), range:<10-100 ng/L) were significant higher than those measured in the Hannover cohort (14.4 ±1 5.1 ng/L (n=60), range: <10-78 ng/L). The OTA levels of 13 samples were measured with concentrations≥ LOQ. The burden of breast milk in different lactation stages, differentiated by colostrum, transitional milk and mature milk, did not differ in the 2 samples collectives Dortmund and Hannover. The infants' exposure was assessed by calculating their OTA intake via human milk. These results were then compared to the recently re-evaluated Tolerable Daily Intake (TDI) of 3 ng/kg body weight/day. In 29% of the cases (with 26 milk samples), the TDI of 3 ng/kg body weight/day was exceeded.In summary, infant exposure to OTA with human milk in Germany is usually low compared to several other countries. Given that in some cases the TDI is exceeded, further efforts to regulate OTA levels in food with the aim of reducing the contamination should be made to minimize the exposure of lactating women to OTA.