Probably a hurdle technology i.e. a bit of everything including storage temperature control and a code life. It is not easy to lower the water activity in ready to cook or eat foods to the value of 0.935. Possibly, it would be equivalent to more than 10% of NaCl in your product and please remeber that other salts including phosphates are of a much higher numbers of daltons and consequently lower molatity to change your Aw significantly. There is a significant inhibition of the germination of Clostridium spore in the presence of NaCl but apparently less when glucose or sorbitol are are used and they may be common ingredients in surimi. Any temperature processing would have a significant impact on vegetative cell and spore survival and the type E would be more affected than others. For more detailed review please refer to the FDA HACCP link http://vm.cfsan.fda.gov/~dms/haccp-2m.html as a starting point that would also contain lots of other valuable cross-references. But apart from anything else you would need to know your product and possible origins of various Clostridium strains that in a composite product like fish-cake may come from various sources such as surimi, starches, other ingredients or even cross-contamination during processing.
Andrew Strak
----- Original Message -----
From: Pacific Management Resources, Inc.
To: seafood@ucdavis.edu
Sent: Thursday, August 03, 2000 11:05 PM
Subject: water activity in fishcakes.
Date: August 3, 2000
To: Seafood List
Email: seafood@ucdavis.edu
Re: water activity in fishcakes.
I have a question about water activity in surimi-based fishcakes. Fishcakes (steamed, fried and broiled) are usually vacuum-packed and sold refrigerated. C. bot is a concern. The water activity of these fishcakes runs about 0.96-0.97.
What can be added to lower the water activity to below 0.935 to inhibit growth of C. bot? I have looked at many different fishcakes and imitation crab products sold in the refrigerated case. Either they are all out of compliance (possible) or else they have a recipe that results in a product with lower water activity.
What will do the job without fundamentally changing the nature of the fishcakes? Candidates. Carageenan? Sorbitol? Tripolyphosphate? More sugar and salt? More starch? Any other ideas?
Thanks for any help....John
John Kaneko MS, DVM
Project Director,
PacMar, Inc.
3615 Harding Avenue, Suite 409
Honolulu, Hawaii USA 96816
Ph: (808) 735-2602
Fax: (808) 734-2315
Email: pacusa@pixi.com
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