Dear Kevin,
I can not compete with the knowledge and wisdom of Peter on fresh fish;
however, having observed mahi mahi handling and processing in several Latin
American countries, I have some observations on the subject, and also on
your e-mail, as follows:
(i) There is a general rule. The more your cut your fish the more you
spread spoilage (and eventually) pathogenic bacteria. Of course, there is a
balance, you can not keep whole fish indefinitely and therefore at certain
point it you would have to cut to eliminate guts and the head ("fish spoil
from the head"); obviously this has to be done in an hygienic and proper way
two conditions and not just one. There is not a definite point when to
headed and gut a fish, it will depend on the specie, fatty and small size
fish, in general, have to be transformed in HG fish sooner than other fish.
(ii) Gutting and heading help but they are not the basis for reducing
fish spoilage rate. The basis is use of ice and proper chilling (again two
conditions and not just one). Not just the use of ice as cosmetic (or
additive) to make happy fish inspectors and fool buyers, but ice to chill
fish as soon as possible after catching and keep it chilled afterwards. Even
if not all the people know this, and as research conducted by Prof. Huss in
Denmark has demonstrated scientifically long time ago; proper and quick
chilling is under current conditions more important than hygiene. Definitely
more important than certain hygiene that is only a "esthetical hygiene"
(just for people's eyes, not necessarily for bacteria). I am not saying that
things can be done without hygiene, I am just saying that what can not be
avoided, at all, is chilling. You do not mention the word "ice" in your
message and this is a strong indication that the actual problem could be,
lack of proper chilling, or just that icing is delayed.
(iii) Mahi mahi contains histidine therefore can develop (and develops)
histamine. Again production of histamine can be reduced by icing. Histamine
formation is strongly dependant on temperature, and could eventually form at
low temperatures (e.g. 4-5 degree C), depending on some normal and
contaminant flora, but even in such a case production is slow down by proper
and quick chilling. Histamine is more related to temperature abuse than to
hygienic (esthetical) handling; therefore a fish can appear acceptable from
a sensorial point of view but histamine content could be above what is
accepted by regulations. Again in your e-mail you do not mention the word
"histamine", that definitely it is a relevant hazard in the case of
mahi-mahi.
(iv) Finally, "poor workmanship" can be always solved with training and
retraining, provided there is somebody that could say and teach how the
right procedure is.
I recommend you the lecture of the following two documents:
(a) The Prof. Huss' manual on fresh fish handling, that you can download
free of charge from:
http://www.fao.org/DOCREP/V7180E/V7180E00.HTM
<http://www.fao.org/DOCREP/V7180E/V7180E00.HTM>
(b) The Fish and Fisheries Products Hazards and Controls Guide (3rd
Edition); published by FDA (CFSAN), that can be downloaded, free of charge,
from:
http://www.cfsan.fda.gov/~comm/haccp4.html
<http://www.cfsan.fda.gov/~comm/haccp4.html>
This two documents will provide you with the knowledge that you need to
solve your problem in practice. Do not lean or trust too much (or only) in
HACCP certifications or similar; outside a pure academic environment or the
marketing gymnastics area, certificates (of any kind) are documents to be
verified for its actual worth, always. There are new things and
developments, we forget what we learned, etc. therefore the only corrective
action to our ignorance is to continue studying, observing and thinking.
Kind regards.
Hector M. Lupin
Senior Fishery Industry Officer (Quality Assurance)
Fish Utilization and Marketing Service
Fishery Industries Division / FAO of the UN
Viale delle Terme de Caracalla 00100 Rome Italy
Tel.: +39 06 570 56459 Fax: + 39 06 570 55188
E-mail: hector.lupin@fao.org
Please visit our website: http://www.fao.org <http://www.fao.org/>
-----Original Message-----
From: kevin lyman [mailto:klyman@tiac.net]
Sent: 07 April 2004 00:02
To: seafood@ucdavis.edu
Subject: Poor workmanship in removing blood from fish bellies
Attn: Peter Howgate & everyone else:
When fish such as mahi mahi are gutted and cleaned, does a poor job of
washing the blood out of the bellies, contribute to foul odors, bacteria
growth, and reduced shelf life. We had some mahi come in which had a lot of
blood in the belly cavities and became extremely smelly. My theory is that
the poor job of removing belly blood after removing the internal organs,
contributed to this condition, and that the product should have either
thouroughly cleaned or rejected at the time of inspection. Any scientific
expertise responses will be appreciated. I am HACCP certified but lack the
scientific knowledge and expertise to know if my observation of this poor
workmanship is the cause of the problem we had. Thanks for your help.
Kevin Lyman
John Nagle Company
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