Spliced feed for The Science Network

Flipping Magnetic Japanese Researchers [SciScoop Science Blog]

Posted:

Japanese researchers have proved it is possible to manipulate magnetic domains in a semiconductor without using magnets. This could lead to more power-efficient and better MRAM.

Melamine Contaminated Milk [Sciencebase Science Blog]

Posted: 29 Sep 2008 04:00 AM CDT

chinese-boy A brief summary and update to the Sciencebase original posts on Melamine in Milk and Melamine Scandal Widens.

Dairy farmers have been feeling the squeeze for years, particularly in parts of the world where technological advancement has been slow in coming and so their profit margins on their milk output have not been lifted by improved efficiency. In order to boost profits milk has been diluted. However, this brings with it the problem of falling quality - dilute with water and measurable concentrations of milk proteins, fats, and sugars fall. Dilution by up to 30% has not been uncommon, which is where melamine (as I’ve mentioned) comes in. Melamine is a small organic molecule with a high nitrogen content that can easily fool the quality control equipment into thinking that nitrogen (from protein) is present at normal levels and so the milk is passed as good.

Unfortunately, it is possible that melamine accumulates
in
the body
and causes toxicity problemsmelamine accumulates in the body and causes toxicity problems - basically damaging the kidneys and forming stones (solid deposits within the kidneys or bladder). Infants fed regularly with milk containing melamine will be particularly susceptible to these effects. As we have seen tens of thousands have been affected and several have died in China. Why this problem is not more widespread, given the rather large number of infants potentially having been drinking contaminated formula-milk for months is unclear.

Hsieh Teh-sheng, director of the Taiwan Urological Association and chief of Cathay General Hospital's Department of Urology told the Taipei Times, that while there is no direct toxicity information on melamine’s health effects on people, the level of melamine found in the milk products is “not particularly high”. He says that kidney stones or other effects blamed on the melamine “could just as easily be caused by other harmful chemicals,” which is a point I discussed in the original post.

However, cyanuric acid is often present in melamine samples and the two can react together to form crystals of uric acid, which can form stones. The current scandal could, whatever the final outcome, provide researchers with useful data on melamine toxicity. That said, if someone were drinking lots of coffee with powdered milk and does not have a lot of fresh water in their diet, this in itself is a risk factor for kidney stones regardless of any contaminants.

Sources in China have now said that Sanlu, which is at the heart of the controversy, was aware that its products were contaminated with melamine as long ago as December 2007. Fonterra, the New Zealand dairy company and 43% stakeholder in Sanlu claims to have approached the Chinese authorities as soon as it heard about the problem but was held back from going public because of the imminent Beijing Olympic Games. One can imagine there were additional pressures that prevented Fonterra from pushing for a solution. But, it cannot blame Chinese regulations for it failing to warn consumers as soon as it knew about the contamination.

Products across the globe containing milk imported from China seem to have been affected and authorities from Australasia and Asia to Europe and the US are withdrawing formula milk, coffee and tea drinks, candies, soup, cheese powder, biscuits, ready-made desserts, and chocolate. however, there are calls from some commentators that the US Food and Drug Administration (FDA) should be more forthright on its recommendations for consumers concerned with the melamine in milk scandal.

For those thinking of testing the products in their store cupboard, there’s a Craigslist item for sale here. It’s described as a “Rapid Melamine test kit—AgraQuant Melamine ELISA test kit”.

But, before you grab your credit card, think carefully whether you’d like to make ELISA (Enzyme-Linked ImmunoSorbent Assay) your friend. It’s a tricky test and probably not one you could rattle off in an afternoon with at least some biomedical background. Also, there’d be no point in testing your Ikea furniture for melamine, the “Melamine” they use is a polymer resin (a plastic, in other words) made from the small organic molecule melamine and formaldehyde, and no there’s no need to worry about using melamine cooking utensils or eating off a melamine-coated kitchen table.

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Melamine Contaminated Milk

Can nutrients in water be traded like carbon? [Earth & Sky Podcast]

Posted: 28 Sep 2008 04:09 AM CDT

Watersheds around the country are creating a market for trading water quality, which is somewhat similar to trading carbon credits. The purpose is to control nutrient pollution in water, which can – for example – cause coastal waters to become toxic to both humans and animals.