Monday, September 22, 2008

Spliced feed for The Science Network

Spliced feed for The Science Network

Sun sets due west on equinox September 22 [Earth & Sky Podcast]

Posted: 22 Sep 2008 04:09 AM CDT

September 22, 2008. The September equinox falls today at 3:44 p.m. At the instant of this year’s September equinox, the noonday sun will be directly overhead at the equator as seen from northern Brazil.

This posting includes an audio/video/photo media file: Download Now

Melamine Scandal Widens [Sciencebase Science Blog]

Posted: 22 Sep 2008 02:15 AM CDT

chinese-babyFour infants in China have died and at least 53,000 are reportedly ill, many seriously so, having been fed milk powder contaminated with the industrial chemical melamine. A three-year old girl in Hong Kong is also ill, but has now been released from hospital, she was the first reported case outside mainland China. Major formula milk producer Nestle says none of its products in China has been contaminated with melamine, although the Hong Kong government says it has found the contaminant in the company’s milk formula.

I guess it’s no surprise that this scandal has emerged after, rather than before or during, the Olympic Games, but that is not something that would be peculiar to China. Governments the world over try to manage bad news and China certainly does not have a monopoly on cover-ups. If melamine is the primary contaminant, then regardless of claims that other compounds may be present, long-term use (six months or so) would be enough for this toxic compound to accumulate in an infant and lead to toxic effects such as kidney stones. The LD50, or acute toxic dose is not entirely relevant if an infant is being fed contaminated milk day after day. Incidentally, LD50 is a measurement per kilogram of body mass, so it is not higher for people than it is for rats, although it may be different because of differences in our body’s biochemistry.

I used to use an analytical instrument when I worked part-time in quality control in a milk-processing plant during my early post-student days. The machine could give you an almost instantaneous printout of fat, protein and sugar levels in the milk passing through the dairy. Those in QC also had to look at the milk for colour and quality and smell and taste it to check for taints (from pipe disinfectants, bacterial action, or contaminants). Indeed, one of the qualifications for the job was to have a palate sensitive enough to detect phenolic (smoky) compounds down to a few parts. It would usually have been quickly apparent if there was a problem with any incoming milk supply and I cannot see how others in the supply chain in China were not duplicitous in this conspiracy.

There could, of course, be other contaminants, I alluded to that in the original melamine in milk post. If someone is unscrupulous enough to add melamine to baby milk falsify protein levels, then there’s no reason why they would use expensive chemically pure material. This would answer partly one of the questions asked by a commenter on the original post. Apparently, th Chinese government reported findings 2565 ppm or 0.25% of melamine in Sanlu’s milk powder. The cost of melamine is relatively high, so what would be the economic justification for such an irresponsible act if it were only increasing the apparent protein level by 1.2%?

The melamine may have been obtained from low-quality sources that are themselves contaminated with other toxic compounds, or it may be high-quality melamine, but stolen to order at some point in the supply chain? It has been suggested that other contaminants may be urea and aminopterin, but I have not seen any official note on that anywhere.

Melamine decomposes on heating, so one commenter on the original post was curious as to how does
survive the
pasteurization and evaporation processes
how does melamine survive the pasteurization and evaporation processes without decomposition used to make milk powder from raw milk.

Apparently, melamine has been mentioned in dispatches across China for more than 15 years, why is it that a pet food scare in 2007, and now this infant formula milk scandal are the only times that the western media has covered the problem?

nissin-cha-cha-dessertIt is becoming apparent that contaminated baby formula is not the only problem. Milk, ice cream, yoghurt, confectionery such as chocolates, biscuits and sweets, as well as any foods containing milk from China have been banned from import into Singapore after the country’s agri-food and veterinary authority found melamine in imported samples. Similarly, Taiwanese authorities seized imported products after notification of contamination from Beijing earlier this month. Japan has recalled various products. Canada’s Food Inspection Agency has warned citizens not to eat a dessert - Nissin Cha Cha Dessert - imported from China that has been found to be contaminated with melamine. The authorities in the Philippines are currently testing.

It is curious, but perhaps not surprising, that the Chinese authorities say not a single hospitalisation case has any connection with contaminated milk. Fonterra, parent company of milk producer Sanlu which is at the centre of the scandal says the whole debacle is one of sabotage and that there is no point in the production process at which melamine could have been added. Fonterra chief executive Andrew Ferrier claims an unknown third party put the banned chemical melamine into raw milk supplied to Sanlu. However, the company new about the contamination on August 2, just ahead of the Olympic Games, and claims that Chinese regulations prevented it from going public at the time.

Melamine Scandal Widens

Autumn Leaves [Sciencebase Science Blog]

Posted: 21 Sep 2008 06:00 PM CDT

google-autumn-logoToday, is the first day of autumn, the fall, and Google is celebrating with a new leafy logo. But, why do leaves turn red in the fall? It’s all down to chemistry. Red pigments known as anthocyanins form in leaves from many plant and tree species at the same time as the green photosynthetic apparatus is dismantled by the plant during which nutrients containing nitrogen (N) and phosphorus (P) are re-absorbed by the plant from its leaves for winter storage. If these nutrients are not resorbed next year’s growth is inhibited. As the levels of green compounds in the leaf falls and anthocyanins rise so the leaves of many species change from verdant to rusty with a range of colours in between.

red-leavesFor more information on why leaves turn red in autumn, check out this page from Wisconsin University. Science Made Simple has a nice explanation too as does Dr David Wilkinson from Liverpool John Moore’s University, and the USDA.

Autumn leaves is a jazz classic about the bittersweet symphony that’s life. My singing group Big Mouth cover it in a medley of standards. I’ve created a playlist of the other stuff we do on Youtube.

This is an updated post Sciencebase from November 2006.

Autumn Leaves

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