Dear Colleagues
Thanks to Walter for his helpful comments and useful research study. As many will know, a significant proportion of the histamine producing species (including mahi mahi and various tunas) implicated in toxicity are caught by longlining. Longline fishing technology involves the setting a line sometimes 30-40km in length with hooks at intervals. A typical fishing pattern is 6 hours set + 4 hour rest + 6 hour haul. Therefore, with a "first in-last out" fishing pattern fish hooked at the start of the set can be in the water ("soak time") for 16 hours. Even under optimum conditions (first in-first out) fish could be in the ater for up to 10 hours. Higher catch rates significantly slow down the haul as the crew have to deal with the catch, regularly tricky live sharks, a secondary target in these fisheries. Yellowfin tuna and mahi mahi longline fisheries fisheries are mainly surface sets (compared to much deeper sets at the thermocline for swordfish, bigeye and bluefin). Surface !
water
temperatures in tropical tuna fisheries are typically 28-30 degrees C, frequently higher. Most fish die on the line and are brought on board dead. Some are alive onboard.
Given the results of Walter's study (mahi mahi reaches 50ppm histamine after 12 hours in seawater at 26 degrees C, see below) it it is easy to see how tuna and mahi mahi can be well on the way to becoming toxic by the time they even arrive on board. My view is that the variability in histamine levels measured on imports of fresh tropical fish of these species is due mainly to the stage of the longline set where they are caught. Furthermore it would appear that the typical longline fishing practices eliminate most of the margin for mistreatment.
Whilst taking Walter's point that testing at import is the only means of control for an import authority, it would be preferable to apply vessel level controls to prevent the development of histamine in the first place. What can be done in terms of onboard practices? Maximum soak time is a critical variable and fishing patterns should ensure "first in -first out" to reduce this. Similarly the length of the set should be reduced when seawater tempertaures are abnormally high. On deck, histamine producers should always be dealt with as a priority over non-histamine producers (eg.sharks) irrespective of catch order. Implementing a HACCP plan onboard runs into the problem that strictly speaking we should deal with each single fish as a batch, since the presence of the hazard depends on the catch history of individual fish. The critical variables are the time since death and temperature. However we have no means of measuring time of death, so use the maximum possible time of dea!
th as a
proxy, or note whether the fish is "live on board". Practically, tracking and monitoring temperature/time of individual fish on deck and in the fish room is extremely difficult on a working fishing vessel, but the use of remote temperature sensors and RFID tags seems to offer some promise of providing HACCP data without interfering too much in vessel operations.
In conclusion, it seems that typical longline fishing practices for tropical tunas and mahi mahi give rise to conditions in which fish can acquire histamine toxicity. The only solution to this problem is through a fundamental re-appraisal of the operation of longline fishing practices. In the meanwhile producers are going to have to suffer trade repressive and costly sampling and testing at point of import.
Yours
Ian Goulding
Fisheries consultant
Megapesca Lda. PORTUGAL
-----Original message-----
From: Pamela Tom pdtom@ucdavis.edu
Date: Sun, 7 Nov 2004 14:12:20 -0500
To: Seafood HACCP Mailing List seafood@ucdavis.edu
Subject: [Spam] Re: Histamine sampling of tuna question
To: Seafood HACCP Mailing List
I'm posting the following response from Walter F. Struszkiewicz (U.S. Food
and Drug Administration) and including links to histamine references.
Pamela Tom
Univeristy of California
Sea Grant Extension Program
===========================================================================
"Consumer illness from the ingestion of decomposed and scombrotoxic fish
remains a major public health problem. Most of the unsafe fish are
received as imported products. There has been a long standing problem of
inadequate attention given to preventing bacterial decomposition at the
point of harvest which results in the production of irreversible unsafe
chemical changes in fish.
"The progression of bacterial decomposition which leads to the formation
of histamine and other biogenic amines begins in the anterior end of a
fish and the highest concentrations of the amines are usually found in the
lower anterior region. These changes are not always accompanied by
obvious odors of decomposition within the muscle. It is necessary to
sample the tissue at the anterior end cutting through the transverse
section (backbone to belly) to have a high degree of reliability in
assessing the safety of the fish. The sample location rather than the
amount of tissue is the important factor. Our publication in the January
2004 issue of the J of Food Protection* documents the rapid formation of
biogenic amines in susceptible fish.
"The reality is that fish are harvested, delivered, transported and
offered for sale in the U.S. that contain high concentrations of histamine
due to bacterial decomposition. These shipments of fish usually consist
of a mixture of very good quality fish commingled with decomposed and
unsafe fish. They may be accompanied by "certificates" alleging an
absence of histamine or decomposition. Our laboratories have identified
scombrotoxic levels of histamine in such shipments and we have had
numerous reports of consumer illness from scombrotoxic fish delivered at
the retail level.
"Until a valid control mechanism is established from the point of harvest
at sea through the delivery of fish, chemical analysis will remain the
only reliable test of safety for scombroid-type fish. "Certificates" and
good intentions will not suffice as substitutes."
Walter Staruszkiewicz
Research Chemist
FDA
Laurel, MD
*Journal of Food Protection: Vol. 67, No. 1, pp. 134141. Effects of
On-Board and Dockside Handling on the Formation of Biogenic Amines in
Mahimahi (Coryphaena hippurus), Skipjack Tuna (Katsuwonus pelamis), and
Yellowfin Tuna (Thunnus albacares) WALTER F. STARUSZKIEWICZ, JAMES D.
BARNETT, PATRICIA L. ROGERS, RONALD A. BENNER, JR., LYNN L. WONG, and JOHN
COOK
SeafoodNIC Histamine Links:
http://seafood.ucdavis.edu/organize/histaminetoxin.htm
attached mail follows:
To: Seafood HACCP Mailing List
I'm posting the following response from Walter F. Struszkiewicz (U.S. Food
and Drug Administration) and including links to histamine references.
Pamela Tom
Univeristy of California
Sea Grant Extension Program
===========================================================================
"Consumer illness from the ingestion of decomposed and scombrotoxic fish
remains a major public health problem. Most of the unsafe fish are
received as imported products. There has been a long standing problem of
inadequate attention given to preventing bacterial decomposition at the
point of harvest which results in the production of irreversible unsafe
chemical changes in fish.
"The progression of bacterial decomposition which leads to the formation
of histamine and other biogenic amines begins in the anterior end of a
fish and the highest concentrations of the amines are usually found in the
lower anterior region. These changes are not always accompanied by
obvious odors of decomposition within the muscle. It is necessary to
sample the tissue at the anterior end cutting through the transverse
section (backbone to belly) to have a high degree of reliability in
assessing the safety of the fish. The sample location rather than the
amount of tissue is the important factor. Our publication in the January
2004 issue of the J of Food Protection* documents the rapid formation of
biogenic amines in susceptible fish.
"The reality is that fish are harvested, delivered, transported and
offered for sale in the U.S. that contain high concentrations of histamine
due to bacterial decomposition. These shipments of fish usually consist
of a mixture of very good quality fish commingled with decomposed and
unsafe fish. They may be accompanied by "certificates" alleging an
absence of histamine or decomposition. Our laboratories have identified
scombrotoxic levels of histamine in such shipments and we have had
numerous reports of consumer illness from scombrotoxic fish delivered at
the retail level.
"Until a valid control mechanism is established from the point of harvest
at sea through the delivery of fish, chemical analysis will remain the
only reliable test of safety for scombroid-type fish. "Certificates" and
good intentions will not suffice as substitutes."
Walter Staruszkiewicz
Research Chemist
FDA
Laurel, MD
*Journal of Food Protection: Vol. 67, No. 1, pp. 134141. Effects of
On-Board and Dockside Handling on the Formation of Biogenic Amines in
Mahimahi (Coryphaena hippurus), Skipjack Tuna (Katsuwonus pelamis), and
Yellowfin Tuna (Thunnus albacares) WALTER F. STARUSZKIEWICZ, JAMES D.
BARNETT, PATRICIA L. ROGERS, RONALD A. BENNER, JR., LYNN L. WONG, and JOHN
COOK
SeafoodNIC Histamine Links:
http://seafood.ucdavis.edu/organize/histaminetoxin.htm
> -----Original Message-----
> From: Pamela Tom [mailto:pdtom@ucdavis.edu]
> Sent: Saturday, October 30, 2004 1:21 AM
> To: Seafood HACCP Mailing List
> Subject: Histamine sampling of tuna question
>
> To: Seafood HACCP Mailing List
>
> A subscriber to this list asked me to post this message. If you have
> information, would you either share via the listserv for open discussion
> or with me privately (pdtom@ucdavis.edu)?
>
> "During my visit to Ecuador a question came up about sampling for
> histamine in tuna. The firm packs headed and gutted tuna (high quality)
> for the US fresh market - Miami Seafood market and NY Fulton Seafood
> market. They air freight everyday. After an FDA inspection they were
> told to sample each fish for histamine by removing at least 50 grams of
> flesh near the neck line fins (instead of the previous tail location).
>
> This type of sampling will destroy the esthetic quality of the fish and
> make it unsaleable in this particular market. How is this matter is being
> handled by other sellers of this product?"
>
> Pamela Tom
> University of California
> Sea Grant Extension Program
This archive was generated by hypermail 2b29 : Mon Nov 08 2004 - 00:50:23 PST