Monday, April 2, 2012

2 cases of botulism linked to tofu

Tofu, sold in NY City, has been linked to 2 cases of botulism. The tofu was purchased by a couple in a NY City store. The tofu was displayed in a non-refrigerated, water filled bin. This is the first cases of botulism in NYC in more than 15 years.

Tofu is made by coagulating soy milk and pressing the resulting curds. The process begins by soaking, grinding, boiling and straining dried or fresh soybeans. Coagulation of the protein and oil (emulsion) suspended in the boiled soy milk is the most important step in the production of tofu. This process is accomplished with the aid of coagulants. Two types of coagulants (salts and acids) are used commercially. The third type of coagulant, enzymes, is not yet used commercially but shows potential for producing both firm and "silken" tofu’. (adapted from Wikeapedia).

Clostridium botulinum spores would survive the boiling and then be able to grow in the non-refrigerated product (in the absence of a secondary inhibitor. Tofu products vary greatly, even in terms of inclusion of antimicrobial parameters.) The spores will germinate and grow in the protein rich, non-refrigerated product. The product sitting in water would ensure a sufficient water activity as well as help support an anaerobic environment, both essential for C. botulinum. As C. botulinum grows, it produces a neurotoxin. If ingested, the neurotoxin enters the bloodstream and shuts down muscle function, potentially leading to death through the inability of the victim to breath.

Tofu is a considered a potentially hazardous food (TCS food) and thus requires refrigeration during distribution, at retail, and by the consumer.

 Tofu suspected of giving botulism to two people in QueensBotulism is a rare but potentially fatal foodborne illness


Saturday, March 31, 2012, 2:18 AM
Read more:

Two people got botulism - a rare but potentially fatal foodborne illness - after buying tofu at a store in Flushing.

The city Health Department said in a release Friday evening that it confirmed one case of the potent form of food poisoning, and suspected another case.

Both of the afflicted are Chinese-speaking Queens residents who recently bought fresh, unrefrigerated bulk tofu from Flushing market. The tofu was not made at the store, and its source is under investigation, the Health Department release states.

"This kind of tofu -- commonly sold in an open, water-filled bin -- is highly suspected to be the source of these cases; however it has not yet been confirmed," the release states.

Fresh, unrefrigerated tofu is used to make fermented tofu and is an ingredient in a popular Chinese dish called chou doufu, or stinky tofu. Anyone who has bought this variety of tofu is urged to throw it away, even if they cooked it, because the toxic spores can survive cooking.

A Health Department spokewoman said neither patient has died of the illness, but declined to comment on their condition. She also declined to name the Flushing store where the two bought the tofu.

"We're still investigating the origin and destinations of the tofu, and because of that we aren't disclosing the name of the store," she said.

Botulism impairs the body's nervous system. Symptoms of botulism include blurred or double vision, weakness or paralysis, poor reflexes, and difficulty swallowing, speaking or breathing. The symptoms usually show up 12 to 36 hours after eating the offending food, but they can also emerge days later. If you ate fermented tofu and experience these symptoms, contact a doctor immediately.

New York City has seen only one other case of foodborne botulism in the past 15 years.

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