I think that your interpretation of Reddy et al is rather conservative.
They carried out botulinum challenge studies and presented 'margin of safety' values as the time between sensory rejection and toxin development. They found very good margins of safety for all MAP fish stored at 4°C. At 8°C, marine fish (cod) had a very good margin of safety (>36 days) while aquacultured species varied from Tilapia (23 days) to salmon (0 days). At 16°C Marine cod had a margin of safety of only 1 day with tilapia and catfish having margins of 0 days and salmon of -1 day. On first reading, one might conclude that MAP aquacultured fish are unsafe. However, they also presented data on air packaged fish and found very similar margins of safety. Air packed salmon at 8°C had a margin of 0 days and catfish and salmon both had safety margins of 0 days at 16°C. MAP tilapia and catfish at 8°C had higher safety margins than air packed fish. Unfortunately the experiments weren't able to give a estimations of error for the results but my reading of them is that there was probably no significant dif
ference in the hazard from temperature abused MAP fish and temperature abused air packed fish. The hazard did not come from the packaging but from the temperature abuse and initial level of contamination with C. botulinum type E spores (100 spores per gram).
MAP of fish has been commonly used in some parts of Europe for a number of years with, to my knowledge, no incidents of botulism.
Graham C Fletcher
Food Microbiologist,
Seafood Research Unit,
Crop & Food Research, Private Bag 92169
Auckland, New Zealand
Phone: 64-9-815 4200 Ex 7018
Fax: 64-9-815 4214
Email: FletcherG@crop.cri.nz
>>> "Douglas L. Marshall" <microman@ra.msstate.edu> 22/6/00 9:48:15 AM >>>
Hi Chong,
The general opinion (FDA) in the U.S. is that modified atmosphere (or
vacuum) packaging of fresh fish is too risky due to the potential for
outgrowth and toxin production of nonproteolytic Clostridium botulinum
(primarily type E) prior to spoilage, especially during mild to moderate
temperature abuse storage conditions. For recent research evidence
supporting this position see Reddy et al., 1999. J. Food Safety 19:171-183.
However, you may be able to prove safety by demonstrating strict temperature
control (<3.3 C) during the entire expected storage life of the product.
FWIW,
Doug
********************************************
Douglas L. Marshall, Ph.D.
Professor & Food Scientist
Department of Food Science & Technology
Mississippi State University
Box 9805
Mississippi State, MS 39762-9805 USA
Ph 662-325-8722
Fax 662-325-8728
http://www.msstate.edu/dept/fst/Homepage
********************************************
-----Original Message-----
From: owner-seafood@ucdavis.edu [mailto:owner-seafood@ucdavis.edu]On
Behalf Of chong lee
Sent: Wednesday, June 21, 2000 11:53 AM
To: seafood@ucdavis.edu
Cc: phowgate@rsc.co.uk
Subject: MAP for fish
I wonder if anyone could provide the information on the current status of
MAP on shelf-life extension of fresh fish, primarily processed - e.g.
fillet. There have been some reports in the past, but I found the gas
composition somewhat varies with species and reports. There seems to be no
general agreement on what the makeup of the gas should be. Any
information would be greatly appreciated.
Chong Lee
Chong M. Lee, Professor
Dept. of Food Science & Nutrition
University of Rhode Island
Kingston, RI 02881
Tel. 401-874-2862; Fax. 401-874-2994
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