Mycotoxins are secondary mold metabolites and generally ubiquitous contaminants of food and feed produced by funguses. The most important mycotoxins are aflatoxins-AF (B1, B2, G1, G2), ochratoxin A (OTA), fumonisins (FB1, FB2), zearalenone (ZEA) and trichothecenes (deoxynivalenol-DON, T-2, HT-2). Among the listed mycotoxins, OTA deserves special attention due to several reasons: (1) OTA possesses teratogenic, embryotoxic, genotoxic, neurotoxic, immunosuppressive, carcinogenic, and nephrotoxic properties; (2) OTA is permanently present in various foodstuffs worldwide due to the ecological variety of Aspergillus microfungi and Penicillium. These toxigenic microfungi almost always produce several toxins at the same time, for example ochratoxins A, B, C and citrinin (a powerful nephrotoxin)2. In areas where kidney diseases are common, patients with kidney and urinary tract tumors have higher OTA concentrations in human samples of urine and blood.1
OTA has been detected in foodstuffs of both plant and animal origin. In foodstuffs of plant origin, OTA has been found, in particular, in cereal products, beer, coffee, cacao, chocolate, spices (dried red pepper, chili powder, black pepper, cayenne pepper, nutmeg, coriander, ginger, curcuma), vegetables, green tea, pistachios, figs, raisins, grape juice, wine, liquorice and chestnuts. Foodstuffs of animal origin, such as raw pork meat, pork blood products, kidney or poultry liver, are indirectly contaminated by OTA when animals are fed with contaminated feedstuffs. However, meat products, such as raw ham muscle, cured meats, salami or dry-cured ham, may also be contaminated by OTA in a direct way. Cheese is also directly contaminated by OTA.
Ochratoxin A is a nephrotoxic mycotoxin with carcinogenic properties and it seems that OTA could be "a complete carcinogen" (not only an initiator, but also a promoter of cancer).2 Penicillium verrucosum fungus is a major OTA producer in cereals. OTA often co-occurs in food with other mycotoxins (citrinin-CIT, penicilic acid, fumonisin B1-FB1, aflatoxins-AF) which exert nephrotoxic, carcinogenic or carcinogen-promoting activity.
For lowering pre-harvest contamination, treatment of field crops with fungicides is the traditional technique. The application of insecticides that work against insects (grape-berry moth (Lobesia botrana and Cochylis sp.) that spread ochratoxin producing fungi can also be used successfully to lower OTA levels in grapes and coffee. A strict link was observed between the number of perforations caused by these larvae and OTA concentrations in grapes. Bacillus thuringiensis bacteria significantly inhibits the growth of OTA-producing fungi on grapes. In coffee, the coffee berry borer (also called broca), Hypotenemus hampei, has been shown to spread OTA. Insecticides controlling these insects could be successful in lowering the OTA contamination of coffee beans. Unfortunately, contamination cannot be completely avoided. Therefore, there is an increased focus on effective methods of detoxification for mycotoxins present in foods, and on the inhibition of mycotoxin absorption in the gastrointestinal tract. Because OTA is a moderately stable molecule that can survive most food processing, such as roasting, brewing, and baking to some extent, several strategies are used for the detoxification or decontamination of commodities containing ochratoxins. These can be classified as physical, physicochemical, chemical, and (micro)biological approaches.3
Few European countries determined maximum allowed levels of OTA in meat products: Denmark, Estonia, Romania and Slovakia. However, data on other important mycotoxins in meat products are lacking and the European Commission did not set regulations for such products even though this type of food is consumed in Europe on a daily basis.
- Deleterious Effects of Mycotoxin Combinations Involving Ochratoxin A
- Producers and Important Dietary Sources of Ochratoxin A and Citrinin
- Chemical, Physical and Biological Approaches to Prevent Ochratoxin Induced Toxicoses in Humans and Animals