B. cereus about contamination – part 1

One thing is known, you either admit you have contamination problems or you can bury your head in the sand. It is that simple. Contamination can be minimized and kept to a minimum as long as you know it is there. Many companies won’t admit it and that is a problem. Since this is a big topic I am planning to split this into 3 posts.

Contamination can come from a variety of sources. Some off the top of my head are: 

  1. Raw Material 
  2. Dead spots in the process loop 
  3. Bad cleaning procedures

I will explain some examples and what was done in those instances.

1. In graduate school, we were working with a fungus where we would grow it on a semisolid medium with shredded wheat as the solid support. Well, the first time we made the medium and let it sit for a day, we had bacterial contamination on the medium. As it turns out, there was a Bacillus sp. that contaminated the shredded wheat in very minute quantities. When we sterilized the shredded wheat, it helped the bacterium to grow by reactivating the spores present. To alleviate this issue, we used a process called Tyndallization. Basically, we sterilized the material twice with a 1/2 day pause in between. This allowed the spores present to germinate and then we were able to kill them during the 2nd sterilization step.

I will cover contamination types 2 and 3 in my next 2 posts.

David Slomczynski, Ph.D; Geometrick Enterprises

 

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