Risk analysis of ochratoxin A in the frame of food safety: Exposure assessment.

Ochratoxin A (OTA) is a toxic secondary metabolite produced by certain species of the fungal genera Aspergillus and Penicillium that may contaminate foods and feeds. This mycotoxin has nephrotoxic, hepatotoxic, neurotoxic, immunogenic, teratogenic, and carcinogenic properties in animals. In humans, chronic exposure to OTA has been related to the development of tumours in the urinary tract, and to the Balkan endemic nephropathy. The International Agency for Research on Cancer classified OTA as possibly carcinogenic to humans. OTA can be found in several foods of vegetal origin, such as cereals and derivatives, beer, coffee, wines and grape juices, nuts and dried fruits, cocoa and derivatives, spices, and in certain animal by-products. Such ubiquity may lead to a chronic exposure by humans. The assessment of the exposure of a population to a food contaminant, in this case, OTA, can be done through two main procedures. In the first case, through the detection of this compound in the foodstuffs that are supposed to be contaminated by OTA and the study of the consumption habits of the assessed population regarding the mentioned foodstuffs. In the second case, through the use of biomarkers of the exposure, which implies the detection of OTA or its metabolites in biological fluids of individuals of the selected population. The general objective of this work was the evaluation of the exposure to OTA of certain groups of people who live in the Spanish region of Catalonia, through the estimation of the daily intake of the toxin. For this, the procedures mentioned above were followed: possibly contaminated food products were purchased in this region, and consumption data by the inhabitants were collected. Biomarkers of exposure were also studied, and the collected fluids were blood plasma and urine. Occurrence in certain foodstuffs and in body fluids confirmed the exposure of the studied population to OTA. Contamination levels in the analysed foodstuffs were below the limits set by the European Commission, and the occurrence in most cases was below the 50%. In the case of biomarkers, occurrence was almost 100% in plasma, lower in urine (12.5%), and it was observed that the metabolite ochratoxin alpha had a higher incidence (60.6%) in urine than OTA. No correlation was observed between OTA levels in plasma and the consumption of possibly contaminated foodstuffs, but significant correlations were observed between OTA and its metabolite ochratoxin alpha in urine and food consumption. Differences in the results could be observed when the population was classified by gender and age, although a general tendency among the studies of this work could not be established. Regional or seasonal variations of the exposure were not statistically significant. The daily intake of OTA was estimated by deterministic and probabilistic methodologies, by modelling food consumption and contamination data. It was also estimated by considering the levels of OTA in plasma, by means of theKlaassen equation. Mean and median results of daily intake obtained through both methodologies were below the suggested by the European Food Safety Authority (17 ng/kg bw/day): up to 3% of that value, in the first case, and up to 10% in the second. However, outliers were observed when the estimation was done from OTA levels in plasma: such values ranged from 14 to 43 ng/kg bw/day. Therefore, exposure to OTA will not produce adverse health effects to the general assessed population, but further efforts should be invested in order to minimize the exposure, as extreme cases of exposure were observed.

Full-text available at: http://hdl.handle.net/10803/52802