"What it requires is that first of all you identify the hazards: Where in your production chain can contamination occur? This could be a simple matter of cooking a product to kill bacteria and making sure that the product is actually brought to that temperature."

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However, on many occasions, I examined normal blood and normal tissues and there was no possibility of overlooking bacteria or confusing them with granular masses of equal size. I never found organisms. Thus, I conclude that bacteria do not occur in healthy human or animal tissues.

— Robert Koch