Hello all,
I recently came across a paper by Yoshinaga and Frank "Histamine-Producing
Bacteria in Decomposing Skipjack Tuna", from Applied and Environmental
Microbiology, Aug. 1982, p. 447-452, Vol. 44, No. 2. This research found
that Clostridium perfringens accounted for 1/2 the histadine decarboxylase
in decomposing tuna.
I believe C. perfringens is more heat tolerant than Morganella or Hafnia (I
was given a D value of 0.3 to 20 minutes at 212 Farenheight).
Kathleen Barber
-----Original Message-----
From: Graham Fletcher [mailto:FletcherG@crop.cri.nz]
Sent: Sunday, November 23, 2003 7:38 PM
To: osnyder@hi-tm.com; byrom@soltai.com.sb
Cc: Carolyn Osborne; seafood@ucdavis.edu
Subject: Re: Cooling time for cooked tuna loins
David
Pete is probably right that 63°C will eliminate histamine-producing
bacteria. Work in our laboratories (Bremer & Osborne, 2000) showed that
it took 1.46 min to eliminate 10 million Morganella morganii ( the most
prolific histamine-producing bacteria) at 62°C and an estimate of less
than a minute at 63°C.
Although you don't describe the history of the tuna before
pasteurization, a fish would have to be pretty seriously mistreated to
have reached this level of contamination. Hafnia alvei (another common
histamine producer) was more heat sensitive that Morganella (Bremer et
al, 1998) so would be even less of a concern. However, if Listeria were
a pathogen of concern to you, you may need to hold product for 5 minutes
at 63°C to achieve a 5D reduction (100,000 organisms) - Bremer & Osborne
1995
If any concern remained regarding histamine-producing bacteria, large
tuna that have not been subjected to a pasteurization step are allowed
to take 6 hours to cool from ambient to 10°C so it would seem
over-zealous to require anything stricter for a pasteurized product.
Bremer, P.; Osborne, C. 1995: Thermal-death times of Listeria
monocytogenes in green shell mussels (Perna canaliculus) prepared for
hot smoking. Journal of Food Protection 58: 604-608.
Bremer, P.J.; Osborne, C.M. 2000: Application of the Bigelow (Z-value)
model and histamine detection to determine the time and temperature
required to eliminate Morganella morganii from seafood ,. Journal of
Food Protection 63: 277-280.
Bremer, P.J.; Osborne, C.M.; Kemp, R.A.; van Veghel, P.; Fletcher, G.C.
1998: Thermal-death times of Hafnia alvei cells in a model suspension
and in artificially contaminated hot-smoked kahawai (Arripis trutta).
Journal of Food Protection 61: 1047-1051.
Food and Drug Administration. 2001. Fish and fishery products hazards
and controls guidance. Third ed. Washington, D.C.:p 88, FDA.
Regards
Graham C Fletcher
Seafood Scientist,
Seafood Research Unit,
Crop & Food Research, Private Bag 92169
Auckland, New Zealand
Physical Address:
Mt Albert Research Centre
120 Mt Albert Road, Mt Albert, Auckland
Phone: 64-9-815 8718
Fax: 64-9-815 4214
Email: FletcherG@crop.cri.nz
Website: www.crop.cri.nz
>>> Peter Snyder <osnyder@hi-tm.com> 21/11/03 3:21:31 a.m. >>>
David,
Pasteurization at 63C would eliminate the histamine producing
vegetative
cells so histamine production during cooling is not a significant
hazard. What survives pasteurization are the spores of B cereus, C
perfringens and Non-proteolytic C botulinum. My research with Dr Juneja
show that cooling meat and poultry from 130F to 45F in 15 hours
controlled the outgrowth of the spores. The 6 hours is a government
number not based on research but rather personal opinion. They have no
scientific paper reference.
Your cooling procedure is safe.
Pete Snyder
David Byrom wrote:
>Dear List,
>Can anybody give me the scientifically proved safe length of cooling
time
>for tuna for the production of cooked frozen tuna loins ?
>
>The tuna are defrosted from -18°C to -2 to 4°C and cooked to a BB
>temperature of 63°C. They are then showered with water and attain a
backbone
>temperature of 30-35° C in approx. 4-5 hours (depending on fish size)
after
>leaving the cooker. Ambient temp. is 25-30°C.The fish are pre-skinned
and
>cleaned, vacuum packed and blast frozen. The BB temp. of the vacuum
sealed
>pack achieves -18°C within 16 hours of being loaded into the blast
freezer.
>
>I have heard widely conflicting ideas on the safe length of cooling
time of
>the fish after cooking, from 6 hours to 24 hours by experienced
seafood
>experts and industry people. I would be grateful if anybody could
>assist.with the correct answer to this issue.
>Thanks
>
>
>David J. Byrom
>Honiara
>Solomon Islands
>
>
>
>
>
>
-- O. Peter Snyder, Jr., Ph.D. Hospitality Institute of Technology and Management 670 Transfer Road, Suite 21A, St Paul, MN 55114 http://www.hi-tm.com Tel 651-646-7077 Fax 651-646-5984 One Worldwide qualified set of food safety guidelines.______________________________________________________ CAUTION: The information contained in this email is privileged and confidential. If you read this message and you are not the intended recipient, you are hereby notified that any use, dissemination, distribution or reproduction of all or part of the contents is prohibited. If you receive this message in error, please notify the sender immediately.
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