Wed, Apr 25, 2012 page16

• Storing opened canned goods in fridge does not cause toxicity: experts 罐頭食品放冰箱　專家：不會鋁中毒

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  Aluminum has recently been found in tap water, donuts, and fried dough sticks. This has also caused an e-mail making the rounds on the Internet, warning that “opened canned foods should never be stored in the refrigerator. Beware of aluminum toxicity,” to once again stir up a debate.

  The e-mail alleges that unfinished satay sauce, corn or tuna in aluminum cans that are stored in the refrigerator can cause chronic aluminum toxicity, and that if symptoms such as depression, fatigue, or chest tightness occur it might be signs of poisoning. It suggests that people should put unfinished canned foods in glass or porcelain containers prior to putting them in the refrigerator.

  The article seemed genuine enough. The name and contact number of an employee from the Industrial Technology Research Institute (ITRI) were even included in the article, making it look quite authentic. As soon as Lin Chieh-liang, director of the Department of Toxicology at Chang Gung Memorial Hospital, heard about the article, he said it was nonsense because all cans have a coating inside and that cans are not even made of aluminum, begging the question how they could cause aluminum toxicity. The ITRI employee whose name appears in the article also said long ago he did not write the report.

  

  A shopper walks down a food aisle at a supermarket in Hong Kong on April 12. 一位購物者四月十二日在香港的超級市場逛食物通道。

  Photo: EPA
  照片：歐新社

  Apparently the only type of cans that currently requires being disinfected at high temperatures are cans made of iron. The cans are coated inside to keep foods from being directly exposed to the iron and spoiling from oxidization. Lin says that a zinc coating is usually applied inside iron cans, and sometimes another layer of coating is also added. Therefore, if anything got out, it would be zinc, but zinc is something the human body needs and it has a very low level of toxicity. Large quantities of zinc would upset the stomach, causing symptoms similar to stomach upsets such as diarrhea. As long as canned foods are stored properly and consumed in appropriate amounts, there is no need to worry.

  Cheng Wei-chih, head of the Division of Food Safety under the Food and Drug Administration, says that as soon as a can is opened it is no longer a germfree environment, and that it is always a bad idea to leave it out for an extended period of time. Canned foods that are not finished could be stored in glass or porcelain containers with plastic wrap covering them before being placed inside the refrigerator to avoid cutting oneself on the sharp edges.

  (Liberty Times, Translated by Kyle Jeffcoat)

  最近不僅是自來水含鋁，甜甜圈、油條含鋁，也使得「吃不完的罐頭千萬不要直接放入冰箱！小心鋁中毒！」這則流傳網路的郵件，再度引起討論。

  

  Canned goods on shelves at a supermarket in Taipei on August 4 last year. 罐頭食物去年八月四日擺在台北超級市場的架子上。

  Photo: Yang Jiou-yin, Liberty Times
  照片：自由時報記者楊久瑩

  郵件認為包括沙茶醬、玉米粒以及鮪魚罐等「鋁製」罐頭，吃完之後如果直接冰入冰箱冷藏，將造成慢性鋁中毒；若因此出現包括情緒低落、疲倦、胸悶等症狀，都可能中毒了。建議民眾將未食用完的罐頭食物置於玻璃瓶或陶瓷容器內，再放進冰箱。

  整篇文章不僅言之鑿鑿，還留下工業技術研究院人員姓名與聯絡電話，看起來似乎真實性十足；不過，林口長庚醫院臨床毒物科主任林杰樑一聽，便說這根本「亂講」，這些罐頭內層都有塗膜、也不是鋁罐，怎麼可能鋁中毒？被點名的工研院人員更早已發聲明澄清，該文並非他的報告。

  據了解，目前需要高溫殺菌的罐頭，幾乎都是鐵罐；而且為了避免食物直接跟鐵接觸、造成氧化變質，內層還有塗膜。林杰樑表示，很多鐵罐內面塗的是鋅，部分額外再塗佈一層膜。也因此，如果要溶出、也是鋅溶出。不過，鋅是人體必要元素、毒性相當低，除非是大量食用，可能造成腸胃刺激，引起腹瀉等類似腸胃炎症狀，只要罐頭保存得當，適量食用，並不需要過度擔心。

  食品藥物管理局食品組科長鄭維智表示，罐頭一打開，就不再是原本的無菌環境，久放本來就不對；吃不完的罐頭食品，倒入玻璃或陶瓷容器中，包上保鮮膜再放入冰箱，更可以避免被罐口鋒利處割傷。

  （自由時報記者洪素卿）

  For your information

  TODAY’S WORDS 今日單字

  1. fatigue n. 疲倦 (pi2 juan4) 例: Fatigue is one of the main side effects of the drug. (疲倦是這個藥物的主要副作用之一。) 2. spoil v. 變質 (bian4 zhi2) 例: If you don’t store it well, it will spoil within a day or two. (若你不儲存好，過一兩天就會變質。) 3. germfree adj. 無菌的 (wu2 jun1 de5) 例: It is important to keep the environment germfree when a surgery is being performed. (開刀時保持無菌環境很重要。)
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