Ochratoxin A exposure assessment of the inhabitants of Lisbon during winter 2007/2008 through bread and urine analysis.

A survey on the occurrence of ochratoxin A (OTA) in 41 bread samples was carried out in the Portuguese capital, Lisbon. Maize (5) and wheat bread (36) and 43 representative urine samples from the Lisbon region were assayed for OTA levels using immunoaffinity column cleanup (IAC) and HPLC with fluorimetric detection (LC–FD). The percentage of OTA-positive samples was slightly higher for maize bread (80%) than wheat bread (70.8%), although, due to its higher consumption, the latter contributes more to OTA exposure, featuring a higher estimated daily intake (EDI). In the urine samples analyzed, both female and male residents displayed similarly high levels of OTA frequency and average contamination. In summary, OTA is a food contaminant of concern and may constitute a hazard for public health through consumption of cereal-based products.