Effects of Thymol, Carvacrol and Some Weak Organic Acids on Growth and Ochratoxin A Production by the Food Spoilage Aspergillus ochraceus

Contamination of foods and feeds with mycotoxins represents a high risk for human and animal health. One of the toxins of growing importance in the last decade is ochratoxin A (OTA), a nephrotoxic mycotoxin with carcinogenic and teratogenic properties in rats and possibly in humans (group 2B) (1). Aspergillus ochraceus (Ao) is an important contaminant of various substrates, such as cereals, and produce OTA (2). In humans, dietary exposure to OTA has been associated with Balkan endemic nephropathy, a chronic kidney disease linked to tumours of the renal system (3). OTA is highly nephrotoxic and may cause both acute and chronic lesions of kidneys. Similarly, neoplasia in kidney have been reported in the Bulgarian cases of mycotoxic porcine nephropathy. OTA is a moderately stable molecule that remains unaltered during most processes of food transformation and may undergo bio-concentration in some animal tissues/organs reaching concentrations in meat products that are not acceptable for human consumption (4). Moreover, this mycotoxin has been detected frequently in cereal products (5). The consumer demand for the reduced use of chemical preservatives in food has prompted the search for alternatives to fungicides in the control of postharvest diseases. Likewise, chemicals usually applied during cereal storage are becoming less favoured (6). New strategies to reduce and prevent the spoilage of cereals during storage include the use of antifungal plant extracts or weak organic acids (7). The aim of this work was to evaluate the inhibitory effects of phenolic components and weak acids on the growth and OTA production by Ao.