Q&A: How dangerous is botulism?

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Question 1: What tainted the milk powder?

"Tests (of whey protein concentrate) indicated the potential presence of a strain of Clostridium in a sample, which can cause botulism,” New Zealand-based Fonterra, the world’s biggest dairy exporter said in a statement released on August 3. Whey protein concentrate is the basic ingredient for producing milk powder.

When people talk about this incident they call it “poison milk powder” case. But Clostridium botulinum, the bacterium found in the tainted milk ingredient, is harmless to human beings. What is poisonous is botulism, which is produced by Clostridium botulinum under anaerobic conditions.

Less than 1 microgram of botulism can result in death. Botulism toxins mainly work on nervous system. The symptoms of botulism could be blurred vision, pupil dilation, difficulty with talking, dyspnea, dizziness, muscle weakness even paralysis.

If Clostridium botulinum, rather than botulism, is found in food, then the food will not necessarily lead to symptoms of botulinum. For adults, small amount of Clostridium botulism can be broken down through body’s natural metabolic pathways.

Question 2: How to avoid the toxin produced by Clostridium botulinum?

It’s known that the suitable temperature for Clostridium botulinum’s growth and toxin production is between 18 and 30 degrees Celsius.

If the temperature is below 15 degrees Celsius or above 55 degrees Celsius, Clostridium botulinum will stop growing. Condition with pH scale higher than 9 or lower than 4.5 will have the same effect.

Botulism has low tolerance for heat and can be damaged when being heated to above 75 degrees Celsius for 30 minutes, or 100 degrees Celsius for 10 minutes.

Another statement published by Fonterra may explain why there was no report about poison case caused by the tainted whey protein concentrate.

On Aug. 4, Fonterra said on its website that “the combination of low pH and ultra-high temperature treatment gives us complete confidence” that beverages and yoghurts of Coca-Cola and Wahaha, which are among the affected, are safe. In the case of Vitaco, the ultra-high temperature treatment gave Fonterra the same confidence.

Question 3: What’s the hidden danger?

The spores of Botulism also cause concern. The bacteria produce spores which are very hard to kill. These spores can survive under high temperature or low temperature, or in a very dry environment. Some bacteria’s cells can be killed in 10 minutes at 70-80 degrees Celsius. But spores can survive for a few hours between 120 and 140 degrees Celsius. It means spores will not be killed by boiling.

If spores of Botulism exist in milk powders, it causes Botulism toxin. Compared with adult, infant are more easily affected by Botulism toxin, because on one hand infants are main consumers of milk powders, and on the other hand, their intestine are not fully grown. So, people should avoid purchasing the contaminated milk products.

Special coverage on tainted milk imports:

• Fonterra promises 'extreme care' in Taiwan trade
• New Zealand farmers head apologizes to China for dairy scare
• Less loopholes for int'l firms in China
• 3 foreign dairy producers exempt from punishment
• Dairy firms hit with fines
• Fonterra tainted milk scraps luster of New Zealand pureness
• More infant formula recalled
• China's latest effort to improve dairy products safety
• Price-fixing fine adds to Fonterra troubles, dairy prices still high
• Fonterra products recalled in China and abroad

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