Subject: Re: Q: Risk of Post-Sterilisation Contamination

From: [email-masked] (Doug Rice)
Date: Thu, 1 Aug 1996 14:20:03 GMT

In article <[email-masked]> [email-masked] (David JD Bell) writes:
>From: [email-masked] (David JD Bell)
>Subject: Q: Risk of Post-Sterilisation Contamination
>Date: Wed, 31 Jul 1996 07:03:21 GMT

>Can Pasteurisation backfire in a food process?

>In a hypothetical process, is it better to make pastuerisation the
>initial process stage - forming the basis for a totally clean process?
>Or is it better to make it the final process stage to eliminate the
>the risk of post-pastuerisation contamination?

Hello David:

IN MY OPINION.... Pasteurization should be the last step.  A totally clean 
process is esentially an impossibility in the food industry.  If milk is 
pasteurized as it comes into the packaging plant the risk for post 
contamination is very high.  If it is pasteurized after packaging as it goes 
out the door the only real potential contamination will be in the consumer's 
home.

Yes, pasteurization will kill a lot of the beneficial organisms as well.  
Pathogens can compete much better if normal flora are not in abundance.  
Several studies have shown that the cleanest food plants can have the highest 
populations of Listeria.  Hope this info is what you were looking for.

G' day.
Doug

Douglas A. Rice
CSU-Environmental Quality Laboratory Director
Applied microbiology of food, air, water and soil.
[email-masked]
voice:  (970) 491-6503
"Moderation is for Monks, take big bites out of life."
--Lazarus

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From: [email-masked] (James R. Eilers)
Date: Thu, 01 Aug 1996 19:01:10 GMT

[email-masked] (Doug Rice) wrote:
>.  If milk is 

Doug,

While your example is hypothetically correct, I feel it should be
noted that it does not reflect actual dairy pasteurization practices
with which I am familiar.  It has been 5 years or so since I dealt
with dairy sanitation practices, but I don't expect the state-of-the
art has changed that much in so short a time.

Pasteurization of drinking milk, at the in the U.S. is accomplished as
late as practical prior to bottling, but not after packaging.  I can't
think of a process that doesn't involve pasteurization followed by
chilling and then filling & sealing.

These practices serve to make pasteurization as late as practical in
the process, thus to minimize recontamination.  

Jim