33 No. 4
This summary highlights some aspects of the International Union of Food Science and Technology’s recent, informative report on chemical hazards in food. Released in January 2011, this Scientific Information Bulletin presents authoritative science on this important food science issue.
The report covers natural and environmental toxins and contaminants. The group of natural toxins and contaminants are discussed in great detail, including compounds such as lectins, glycoalkaloids oxalates, and cyanogenic alkaloids on the one hand and mycotoxins and shellfish toxins on the other. Mycotoxins are produced by a range of funghi and molds and have a high toxic potential. When talking about natural contaminants in food, they are one of the greatest potential risks to human health. Many of them, like aflatoxin B1, are carcinogenic and may cause liver damages such as ochratoxin. Typical food items that might contain mycotoxins at elevated levels are corn, peanuts, and three nuts. Specific climate conditions, such as high humidity, favor the formation of mycotoxins. In order to protect consumers from potential adverse health effects, many countries have introduced legal limits for mycotoxins in different food items.
Chlorinated compounds are an example of the type of environmental contaminants that may accumulate at high levels in food and foodstuff, mainly because of their persistence in the environment. Several measures have been taken by government authorities to cope with these types of contaminants, including banning some of these substances. For instance, in many countries, polychlorinated biphenyls (PCBs) have been banned from use in industry. This decision also contributed to reducing polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), since PCBs often contain traces thereof. Furthermore, legal limits in food and foodstuffs have been established for many chlorinated substances, including PCDD/Fs. A number of polycyclic aromatic hydrocarbon substances, such as Benzo(a) pyrene, have very high toxic profiles. They can enter into our food through various pathways, including via thermal processing or contaminated oil containing these substances. Since the complexity of this group renders the setting of limits more difficult, specific marker substances are often utilized, for which legal limits have been set in various food items.
There are also contaminants in food that derive from specific processing conditions. For instance, acrylamide is a known carcinogen and is formed during baking, frying, or roasting of various food items. Based upon intensive research conducted to identify the mechanism of the formation of acrylamide, an online toolbox was developed to help food processors reduce the undesirable formation of acrylamide. Other examples of process-derived contaminants are chloropropanols and furans.
Melamine is an example of a contaminant that was illegally added to food to simulate a higher protein content in samples. This was possible (1) since melamine is characterized by a high nitrogen content and (2) the commonly used techniques for protein determination, namely Kjeldahl and Dumas, measure protein via the determination of nitrogen. In 2008, melamine was found at high levels in milk powder, resulting in the death of several babies.
Another group of contaminants found in food results from the residues of pesticides and veterinary drugs that have been used under regulated conditions. Maximum residue limits (MRLs) have been set for many of these substances and food samples are often checked to determine if they are within safe limits.
The report also elaborates on the criteria for how MRLs limits are established. Three aspects are taken into account, namely (1) toxic characteristics of the substance concerned, (2) conclusions from good manufacturing practice, and (3) the availability of appropriate analytical methods to enforce MRLs.
A key factor in enforcing legal limits of target analytes in food samples is the availability of appropriate analytical methodology. Here, various strategies are pursued such as the use of screening methods enabling the laboratories to increase the sample throughput. Afterwards, positive samples are analyzed by confirmatory methods to establish whether these samples comply with legal requirements or not. Methods to be used for official control purposes need to be validated against internationally recognized guidelines. There are trial validated methods available for specific analyte/matrix combinations, but in many cases single laboratories validated methods are applied.
The International Union of Food Science and Technology (IUFoST) is the global federation of national scientific organizations representing more than 200 000 food scientists and technologists from over 65 countries. IUFoST has four regional groupings: ALACCTA representing Central and South America, EFFoST representing Europe, FIFSTA representing the ASEAN region and WAAFoST representing West Africa. IUFoST links the world’s food scientists and technologists.
last modified 30 June 2011.
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