Hi Dipak and All,
I am very interested to read usage of 3-5ppm ozone level. I still can not
imagine how to keep the whole tank of water (applied in situ for
“sanitizing the shrimp”) at 3-5ppm ozone constant in the view that ozone
is very unstable. Do you mean the level on the unit was set at 3-5ppm, in
that case the ozone level in the tank should be much lower when measured
and is difficult to control. By the way, does anybody have the “contact
time” necessary for ozone to kill the bacteria? Which is better, rinsing
(dipping) or soaking, in application? “Soaking” usually brings down shrimp
quality.
I appreciate your point of view in hygienic handling during processing.
But I think, one factor, farm environment (the water source), is the main
source of contamination for certain bacteria like salmonella that can only
be eliminated or reduced by repeat washing at different levels of
processing with the help of sanitizer (chlorine or ozone).
Eddy
"SEAWAVES" <seawavescorp@gmail.com>
Sent by: owner-seafood@ucdavis.edu
01/09/2006 05:49 PM
To
"Ira Somerset" <isomerset@hotmail.com>, <bblakistone@nfi.org>,
<seafood@ucdavis.edu>
cc
Subject
Re: Ozone & chlorine as sanitizers
Hi,
I do agree with Peter and Barbara's views regarding effectiveness of
sanitizers and this is because the sanitizers only act on the surface of
the
product but it can not eliminate the bacterial population within the
tissue
esp gut/gill area. Therefore the only way to regulate microbial count is
to
handle the product very carefully and maintain the temperature below
5~6deg
C. Avoid any cross contamination post harvest.
However, I have found ozone and chlorine very very effective in
eliminating
only surface bacteria. Ozone was more effective at 3~5 ppm but as
mentioned
it should be applied in situ. Otherwise it has absolutely no effect.
Chlorine is effective at 10~20 ppm only and time of application should be
more than 30 secs.
Regards Dipak
----- Original Message -----
From: "Ira Somerset" <isomerset@hotmail.com>
To: <bblakistone@nfi.org>; <seafood@ucdavis.edu>
Sent: Tuesday, January 10, 2006 3:13 AM
Subject: RE: Ozone & chlorine as sanitizers
> Hi~
>
> I have found this question and discussion interesting and recall some
work
> done at NMFS Gloucester a few years ago, but cannot find it. I believe
the
> studies were conducted by Joe Licciardello and his group. As I recall,
they
> were fairly comprehensive studies relating to ozonated ice. The
conclusions
> are unclear in my recollection.
>
> Also, perhaps the International Ozone Institute might have some studies
in
> their archives.
>
> Does anyone have access to those sources?
>
> Ira Somerset
>
> ----Original Message Follows----
> From: "Barbara Blakistone" <bblakistone@nfi.org>
> To: <seafood@ucdavis.edu>
> Subject: RE: Ozone & chlorine as sanitizers
> Date: Mon, 9 Jan 2006 16:02:17 -0500
>
> There is no convincing evidence - convincing to me that is;
> manufacturers of ozonizers might disagree - to suggest that exposure of
> fishery products to solutions of chlorine, or of ozone for that matter,
> significantly reduces overall bacterial counts or of counts of
> pathogens, or increases shelf lives of chill-stored products so there is
> no justification for exposing fishery products to sanitizers such as
> chlorine or ozone.
>
> I did some cooperative studies, when I was at Food Products Association,
> with NCSU, and that's what we found. Ozone offered little significant
> reduction in bacterial counts, and thus shelf life extension was not
> among the benefits. We did see excellent results in bacterial air
> quality improvement and sanitation effects.
>
> Barbara Blakistone, Ph.D.
>
> Director, Technical and Regulatory Affairs
>
> National Fisheries Institute
>
> McLean, VA
>
>
>
> -----Original Message-----
> From: owner-seafood@ucdavis.edu [mailto:owner-seafood@ucdavis.edu] On
> Behalf Of P Howgate
> Sent: Saturday, January 07, 2006 7:02 AM
> To: seafood@ucdavis.edu
> Subject: Ozone & chlorine as sanitisers
>
>
>
> Ref. Use of chlorine in fish processing.
>
> There are only a few studies on the formation of carcinogens or possible
> carcinogens from the exposure of fishery products to chlorine. Following
> is a bibliography of references I found in a literature search in 1999.
> At that time chlorine was used at quite high levels in poultry wash
> water and the bibliography cites some studies of this process. Mutagens
> are formed on contact of fishery products with high, greater than 100
> ppm, concentrations of chlorine, but the Codex report considered there
> was no risk to human health on exposure up to 10 ppm. However, there is
> no convincing evidence - convincing to me that is; manufacturers of
> ozonisers might disagree - to suggest that exposure of fishery products
> to solutions of chlorine, or of ozone for that matter, significantly
> reduces overall bacterial counts or of counts of pathogens, or increases
> shelf lives of chill-stored products so there is no justification for
> exposing fishery products to sanitisers such as chlorine or ozone.
>
> A correspondent in this discussion referred to adverse health affects of
> chloramine. Chloramine, the result of reacting together chlorine and
> ammonia, is used as a sanitiser by water authorities for sanitising
> potable water and as far as I am aware is considered safe for this
> purpose by regulatory authorities. Safe for humans that is; toxic to
> fish.
>
> Peter Howgate
>
> ***************************
>
> Codex Alimentarius Commission, Codex Committee on Fish and Fishery
> Products (2000). Discussion paper on the use of chlorinated water.
> CX/FFP/13
>
> Ghanbari, H.A., Wheeler, W.B. & Kirk J.R. (1981). The fate of
> hypochlorous acid during shrimp processing: a model system. Journal of
> Food Science, 47, 185-187, 197
>
> Ghanbari, H.A., Wheeler, W.B. & Kirk J.R. (1982). Reactions of aqueous
> chlorine and chlorine dioxide with lipids: chlorine incorporation.
> Journal of Food Science, 47, 482-485.
>
> Haddon W.F., Binder, R.G., Wong, R.Y., Harden, L.A., Wilson, R.E.,
> Benson, M. & Stevens, K.L. (1996). Potent bacterial mutagens produced by
> chlorination of simulated poultry chiller water. Journal of Agricultural
> and Food Chemistry, 44, 256-263.
>
> Johnston, J.J., Ghanbari, H.A., Wheeler, W.B. & Kirk, J.R. (1983).
> Chlorine incorporation into shrimp. Journal of Food Science, 48,
> 668-670.
>
> Lin, W.F., Huang, T.S., Cornell, J.A., Lin, C.M. & Wei. C. (1996 ).
> Bactericidal activity of aqueous chlorine and chlorine dioxide solutions
> in a fish model system. Journal of Food Science, 61, 1030-1034.
>
> Owusu-Yaw, J., Toth, J.P., Wheeler, W.B. & Wei, C.I. (1990).
> Mutagenicity and identification of the reaction products of aqueous
> chlorine or chlorine dioxide with L-tryptophan. Journal of Food Science,
> 55, 1714-1719, 1724.
>
> Richardson, S.D., Thruston, A.D, Caughran, T.V., Collette, T.W.,
> Patterson, K.S. & Lykins, B.W. (1998). Chemical by-products of chlorine
> and alternative disinfectants. Food Technology, 52(4), 58-61.
>
> Schade, J.E. Tsai, L-S., Tong, L., Wilson, R. & MacGregor, J.T. (1990).
> Extraction of mutagens from chlorinated poultry chiller water. Journal
> of Food Science, 55, 635-639, 657.
>
> Sen, A.C., Owusu-Yaw, J., Wheeler, W.B. & Wei, C.I. (1989). Reactions of
> aqueous chlorine and chlorine dioxide with tryptophan,
> N-methyltryptophan, and 3-indolelactic acid: kinetic and mutagenicity
> studies. Journal of Food Science, 54, 1057-1060.
>
> Tsai, L-S., Higby, R. & Schade, J. (1995). Disinfection of poultry
> chiller water with chlorine dioxide: consumption and byproduct
> formation. Journal of Agricultural and Food Chemistry, 43, 2768-2773.
>
> Tsai, L-S., Wilson, R. & Randall, V. (1997). Mutagenicity of poultry
> chiller water treated with either chlorine dioxide or chlorine. Journal
> of Agricultural and Food Chemistry, 45, 2267-2272.
>
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