You don't mention coliform counts, only E.coli counts. If the coliform
counts were the same as the E. coli counts that indicates a focus of
contamination of E.Coli. An area in the post-cook process where an E.coli
contamination occurred and the conditions are such that it allows the E coli
to have a competitive growth advantage over other bacteria. You also didn't
mention Total Bacterial Counts. This could also shed a light on where the
source could be.
If it is an E. coli focal point, the conditions that would suppress other
contaminants and support E. coli in this type process might be temperature.
E. coli are a slight more heat resistant than their coliform cousins. In
addition, they can grow at 45.5C whereas most coliforms are not able.
The cooking should kill the E. coli if it is in the breading since
pre-cooking usually provides enough heat at the surface for a kill. Of
course if the contaminant load is heavy enough, there can be a residual
number of E. coli left after cooking. There is also the concern that a
pre-cook contamination of the fish on the processing line can occur and
there is not enough heat to kill the E. coli below the breading surface.
Can the E. coli be present on the fish coming into the plant? This may be
highly unusual for this process, but again a source of contamination at some
point must be considered.
Larry Wyatt
Larry Wyatt, PhD
VP, Product Development
FoodHorizon Inc
979-696-7654
Fax: 413-674-9126
www.foodhorizon.com
-----Original Message-----
From: owner-seafood@ucdavis.edu [mailto:owner-seafood@ucdavis.edu]On
Behalf Of Hans Morten Henriksen
Sent: Monday, September 08, 2003 10:36 AM
To: seafood@ucdavis.edu
Subject: E. Coli problem
A client had an E. Coli infection on a full day production.
Levels of counts were 10 to 180 counts pr gram in 1 out of 10 to 1 out of
100 products.
The finished product is battered and breaded fish; prefried before
freezing.
We rule out operator infection:
1. Never found on any other product from these operators
2. Nobody can infect that many items with that small infection
3. The staff hygiene is very fine
The fish raw materials are fine; never found any levels of E. Coli, on
similar product or in the actual batch.
We rule out equipment, since no equipment can infect that many products
with that little amount.
Is anybody aware of a similar problem?
Our suggestion could be an infection in the batter or breading; since this
is the only source that is spread out in the finished product during the
whole day.
For the actual production was used:
125 kg predust
175 kg batter mix
400 kg breading
Or it could be an initial infection of the batter-line, but we doubt.
Other explanations are most welcome.
Yours sincerely
Hans Morten Henriksen
Alcedo - Seafood Business Consultants
Ph +45 4447 3150
Fax -45 4447 3151
hmh@alcedo.dk
www.alcedo.dk
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