Two days ago, I sent Unilever a list of questions, in order to better understand the health hazard associated with the recalled Slim-Fast® RTD products. While waiting for a reply, I've been doing some digging on my own.
Based on what I've uncovered, I suspect that the health risk may go far beyond the chance of an upset tummy that would be associated with the Bacillus cereus contamination reported by Unilever. Here's why.
- I found several Slim-Fast Ready-To-Drink ingredient lists on the National Institutes of Health (NIH) website. There are no preservatives in Slim-Fast RTD beverages.
- Slim-Fast RTD beverages rely on an Ultra-High Temperature (UHT) pasteurization process, followed by an aseptic filling procedure (i.e., filling sterile cans under sterile conditions) to ensure product safety and stability at room temperature.
- UHT pasteurization temperatures (at least 250ºF for a fraction of a second) should be far more than is needed to kill Bacillus cereus spores.
If Unilever found Bacillus cereus in a sealed can of Slim-Fast RTD beverage, that means one or more of the following likely happened:
- The UHT pasteurizer failed to reach the necessary temperature; or
- An ingredient of the formula (perhaps the milk powder) contained an unusually high number of Bacillus cereus spores; or
- A cross-connection in the pipes allowed unpasteurized product to contaminate the UHT pasteurized beverage; or
- The filling line was contaminated; or
- The packaging material was contaminated.
It's clear from the scope of the product recall that this is not a one-shot problem. Whatever conditions enabled Bacillus cereus to contaminate Slim-Fast RTD beverages have been in force for a while.
Bacillus cereus is not an especially heat-resistant bacterium. It is killed by temperatures that will leave more heat-tolerant pathogens such as Clostridium botulinum laughing – and asking for more.
I don't know whether the levels of sugar in the Slim-Fast RTD formulas are high enough to prevent the growth of Clostridium botulinum, along with the production of its deadly toxin. Perhaps this weight-loss beverage is an inhospitable environment for bacterial growth. I certainly hope so!
Otherwise, Bacillus cereus might be the least of Unilever's worries.
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