Hi,
How much C perfringens would there be? It is primiarly a meat and
poultry pathogen. There might be 50 spores per gram in hamburger. It
should be in the spore form when the tuna is caught. It grows rapidly at
110F. But it stops growing in most meat at 59F. If it were in tuna, I
would not expect it to be more dangerous than in hamburger.
Pete Snyder
----------------
Barber, Kathleen G. (BB) wrote:
>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, Ph.D. Hospitality Institute of Technology and Management 670 Transfer Rd, Suite 21A, St. Paul, MN 55114 http://www.hi-tm.com Tel 651-646-7077 Fax 651 646 5984 One worldwide set of qualified food safety guidelines
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