Tuesday, November 25, 2008

Melamine Poisoning: “ Tip of the Ice Cream”

Like many similar incidents in the past, the melamine poisoning scandal is just a symptom of a decadent global food system characterized mainly by corporate greed and government neglect. The government ridiculously tries to show it is doing something to address the problem by parading to the media hurriedly confiscated milk product, yet at the same time, it downplays the dangers by echoing a familiar corporate whitewash that human will have to ingest unrealistically huge volume of contaminated milk to be poisoned. Just as quickly, Nestle and other companies put out expensive adverts proclaiming that their products are safe, even without undergoing the appropriate tests. These short-sighted and self-serving knee-jerk reactions do not protect the health of consumers but perpetuates the pathetic state of affairs as far as safety is concerned.

Food safety has been a serious concern of government and corporations, particularly with the advent of corporate globalization. WTO provisions related to food safely, for example, clearly subordinate protection of health and environment to corporate interest. Countries, especially the weaker countries, are forced to import food products contaminated with toxic chemicals or substances. Any attempt to ban or restrict such harmful substances, even those already banned in other countries, is met with fierce resistance by corporate giants and their host countries. Such is the case, for example, for pesticides, artificial sweeteners and additives, GMOs, and now melamine.

Exposure to melamine and related chemicals, in fact, is not new. Melamine is a triazine synthetic chemical used, usually with formaldehyde, in a wide range of products such as kitchen dishes and utensils, formica, laminate flooring, whiteboards, furniture, cleaning agents, fabrics, glues, colorants, flames retardants, fertilizers and drugs. Melamine is also a metabolite of cyromazime, a triazine pesticide commonly used in vegetable and chicken farms. In 1987, melamine was demonstrated to be present in coffee, orange juice, fermented milk and lemon juice, originating from migration of melamine from the cup made of melamine-formadehyde resin. From 1979-1987, there was widespread melamine contamination of fish and meat meal in Italy and in 2004, there was nephrotoxicity outbreak in pets in Asia. Again, in 2007, thousand of cats and dogs, mostly in the US, became seriously ill or died of acute renal failure after eating pet food contaminated with melamine and related triazine compounds such as ammelide, ammeline trichloromelamine and cyanuric acid. Hogs, chicken and fish were also found to be contaminated with melamine and cyanuric acid. Cyanuric acid is a common disinfectant used in swimming pools together with chlorine. Cyanuric acid was used as an ingredient in herbicides and is also used in the production of melamine and sponge rubber. It is also an intermediate chemical in the bacterial degradation of melamine and in the production of chlorinated bleaches and whitening agents. Trichloromine is the chlorinated form of melamine and is mainly used as disinfectant and cleaning agent.

Melamine may cause adverse reproductive effects, may affects genetic material and may cause bladder cancer based on animal data. It may also cause skin, eye and respiratory tract irritation and irritation of the digestive tract with nausea, vomiting and diarrhea, and may damage the urinary system. Cyanuric acid and trichloromelamine have pretty much the same spectrum of toxicity as melamine. However, cyanuric acid and trichloromelamine have the greater toxicity potential, particularly, in causing kidney damage, development toxicity and cancer.

By themselves, melamine and cyanuric acid are considered to be of low acute toxicity by regulatory agencies based on standard ask assessment for each chemical. It is from this limited risk assessment that official tolerance level (e.g., “15 cups of milk per day fro several months) are derived. However, multiple source and multiple chemical exposures, including exposure to both melamine and cyanuric acid (which has been found to be much more toxic in combination), is the more likely exposure situation and this should be the basis for assessing risks to human health. Other important triazine compounds must also be considered in the assessment of risks. For example, the triazine herbicides are known to cause neuroendocrine and endocrine related developmental, reproductive and carcinogenic effects.

Despite the limited scientific data and the low acute toxicity attribute to melamine and related traizine compound, much can be said about the potential harm that these chemicals pose to animals and human being. The mechanism of rental toxicity melamine and cyanuric acid is well established and that acute or chronic exposure would likely result in adverse renal toxicity that could lead to renal failure. Existing empirical and scientific data indicate that exposure levels sufficient to cause harm likely to be reached under present circumstances. In fact, the European Food Safety Authority, despite using the conservative risk assessment methodology, came up with this statement, “ in worst case scenarios with the highest level of contamination, children with high daily consumption of milk toffee, chocolate or biscuits containing high level of milk powder would exceed the TDI (tolerable daily intake)”. This assessment did not consider potential additional exposures likely to occur in developing countries, such as, cyanuric acid in swimming pools, melamine from the pesticide cyromazine and in contaminated vegetables, fish and meat, and melamine leachate in kitchen wares. Since milk and milk products from products from China were already banned in Europe at the time of the assessment, the worst case scenario for European children did not even consider potential sources from milk and ice cream!

The extent of harm that melamine and related compounds have caused is not at this time but the problem is not just melamine and simply confiscating products will not solve the problem. Government officials should not downplay the dangers of toxic chemicals contaminating food. Mechanisms for appropriate monitoring and timely intervention should be established. Food safety should be placed high in the political agenda and greed, corporate and otherwise, eliminated. Safe food should be put in the hands of the people!

Original article by:
Romeo F. Quijano, M.D.
Department of Pharmacology and Toxicology
College of Medicine, University of the Philippines