The last few months have witnessed raging controversies arising out of serious public health concerns about Bisphenol A, an important ingredient of some packaging systems, and the large-scale practice of adulteration of milk and milk products with melamine in China. While the former is more a debate-based issue, the latter is a serious breach of propriety as it has affected not only many infants in China itself (four fatalities have been reported so far) but also many products in other countries like dairy products, baby foods, biscuits and chocolates that have been either exported from China or manufactured using Chinese milk powder as an ingredient.
Bisphenol A (normally abbreviated as BPA) is a synthetic chemical compound that is a key monomer in the production of polycarbonate resins and epoxy resin lacquers that are used to line metal cans and closures. It is also used as antioxidant in plasticisers in PVC formulations. There are other non-packaging applications as well but these do not relate to food contact. It also pollutes the environment as it interferes with nitrogen fixation at the roots of leguminous plants.
BPA is normally found to leach from can surfaces into canned foods and from polycarbonate baby bottles. The leaching is aggravated at higher temperatures (hot or boiling water in baby bottles, microwaving or heating of canned foods, cleaning polycarbonate containers in a dishwasher or by using harsh detergents). Exposure to BPA is quite widespread. A US study carried out by CDC between 1988 and 1994 found BPA in the urine of 95 per cent of adults sampled and another study carried out in 2003-2004 established that 93 per cent of adults and children tested showed traces of the chemical. Therefore, a very high percentage of the population is at risk. Foetuses, infants and children around puberty are considered most at risk; the former are especially sensitive as their immature detoxification systems render them more vulnerable and since they are at a delicate stage of development.
While there is no doubt about the fact that BPA is an endocrine disruptor and hormone disruptor causing negative health effects significantly associated with heart disease, diabetes, prostate problems, genital changes, predisposition to cancer etc., the debate is about what is a “safe” exposure level in humans.
The FDA and the American Chemistry Council have long steadfastly maintained that exposure levels are not sufficient to warrant a ban on BPA and the majority of tests carried out so far are based on testing on animals and not human beings. In fact, the EPA considers exposures up to 50 micrograms per kilogram of body weight per day to be safe although this is more a guideline than a level established by conclusive tests. Infants fed with baby formulae from polycarbonate bottles could consume up to 13 micrograms of BPA per kilogram of body weight per day. The present debate has been triggered by fresh reports and several earlier studies on animals, the most sensitive of which have shown negative effects at much lower doses than this figure.
The first study of the effects of BPA on human beings was carried out by Iain Lang and his associates and the findings were published in the September 2008 issue of the Journal of the American Medical Association. The cross-sectional study of almost 1,500 people assessed exposure to BPA by testing the levels of the chemical in urine and found them to be high enough to be significantly associated with heart disease, diabetes and abnormally high levels of some liver enzymes. The National Toxicology Program (NTP) has also released a recent report that contradicts an earlier FDA report endorsing the safety of BPA used in baby bottles. While the NTP report does not recommend an outright ban on BPA, it emphasises the need for more research to understand how it affects human health.
The Canadian government has chosen BPA for more careful study along with about 200 other substances. About 5,000 Canadians will be monitored for BPA levels as a part of the Canadian Health Measures Survey. The Canadian Health Minister has announced that the government intends to ban the import, sale and advertisement of baby bottles containing BPA and many leading retailers like Walmart and Toys-R-Us have stopped selling bottles, food containers, cups and pacifiers containing BPA at their Canadian stores. Walmart will also be phasing out polycarbonate baby bottles in all their stores in the U.S.A. by early 2009.
On the other hand, a spokesman for the tinplate can industry has said that unless cans are lined with BPA based epoxy resins, E. coli and botulism poisoning will be rampant in canned foods, probably the reason why FDA is wary about banning the use of BPA.
Tainted milk powder
Milk powder supplied by many major milk producers in China has been found to be tainted with melamine and this has caused a major scandal there resulting in severe embarrassment to the local authorities. The melamine is believed to have been added to milk to give the impression that it has a high protein content and to mask the fact that it has been watered down. Protein content is generally measured by checking the nitrogen content and melamine contains high levels of nitrogen. The ingestion of high levels of melamine causes kidney stones and can ultimately result in kidney failure over a period of time.
As per the latest figures, some 53,000 children have become sick after consuming the contaminated milk powder and four deaths have been reported so far. According to the European Food Safety Authority (EFSA), in the worst case, children that consume biscuits, chocolates and other foods made from the contaminated milk powder could exceed the tolerable daily intake of the chemical by three times. The tolerable daily intake of melamine is 0.5 milligrams per kilograms of body weight and the reported levels in Chinese baby formula are as high as 2,500 milligrams per kilogram of body weight.
According to news reports, more than 12 countries have now either banned or recalled milk products originating from China. Tesco have pulled milk products from their ethnic goods shelves on the advice of the Food Standards Agency. The whole business has made a serious dent in the image of Chinese products, which were already adversely affected by recalls of toothpaste and food products due to adulteration or contamination earlier this year.