Another lethal danger in storing Salmon.... Vacuum packing.

[precookingsmoker]

Sent: Wednesday, November 10, 2010 8:31 AM
To: [email protected]
Subject: Question on Re-freezing "home-cured" commercial fish.

Thank you for any consideration of my question.
I have purchased frozen Salmon from a local food chain market(WinCo).
I will do a brine followed by a cold, then a hot smoke at proper
temperatures and periods of time to obtain smoked salmon.

My question; Is it safe to vacuum seal and RE-FREEZE this newly smoked
salmon for longer storage of up to 1 month?
Thank you. -Larry

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Dear Larry,

Yes, it is safe to seal and re-freeze smoked salmon for a month.  It might last longer (the problem is rancidity, but the vacuum packaging helps to minimize the oxidation).

Be sure to thaw your product in the refrigerator.  If you remove it from refrigerated conditions, then you must open the package to prevent the potential growth and toxin production by Clostridium botulinum type E bacteria which can occur in low oxygen conditions created by the vacuum package.  The smoking temperature is not sufficient to destroy C. botuluninum spores in the product.  Refrigeration below 38F also inhibits growth. This web site explains the risks of vacuum packaged seafood which must be refrigerated: http://seafood.ucdavis.edu/pubs/vacuum.htm   .

Kenny Lum, Seafood Products Association President, recommends that the smoked fish be rapidly cooled after smoking and before vacuum packaging.  That would reduce the risk of high temperature exposure in reduced oxygen conditions. 

Pamela Tom, California Sea Grant Advisor
Mailing Address:
Pamela Tom
University of California

Food Science and Technology Dept.
One Shields Avenue
Davis, CA 95616  USA

Web:    http://seafood.ucdavis.edu (UC SeafoodNIC)
            http://foodscience.ucdavis.edu (UC Davis, Food Science & Technology Dept.)

E-mail: [email protected]

[BuyLowSellHigh]

There is no problem so long as you adhere to the broad an general handling guidelines for meats, poultry and fish  -- keep it cold, below 40 °F.  Vacuum packaging creates an an anaerobic environment, which is what Clostridium botulinum needs to grow and develop.  That bacteria is a spore former and it grows and develops from the spores.  The spores themselves are not toxic, but they are the seed for the bacteria which produces an extremely potent toxin (one of the most potent known).  Preparation, cooking and smoking of meat, poultry and fish focuses on destroying or inactivating the then present bacteria, but usually are not sufficient to destroy the spores.  For that reason even cooked meats, poultry, fish and low acid foods (green beans is the usual example) need to be kept at temperatures where the spores won't bloom into active bacteria.  In vacuum packaging it becomes more critical because of the anaerobic environment.

So long as you keep that vacuum packaged fish below 40 °F you should be fine.  As she points out, "If you remove it from refrigerated conditions, then you must open the package to prevent the potential growth and toxin production by Clostridium botulinum type E bacteria which can occur in low oxygen conditions created by the vacuum package."  For packaging after smoking, chill first, then vac pack would be preferred.

BTW, this is the same for any vacuum packaged meat, poultry or fish, including the cryopacked stuff in the meat department.

[punchlock]

This is very interesting and important information. I always assumed that vacuum sealing made your food safer. I really appreciate you bringing this to light. A lack of oxygen and bacteria growth is not a connection that I would have ever made.

[BuyLowSellHigh]

Another tidbit I failed to include is about thawing.  Do it cold (like in a refrigerator or ice water) or remove it from the vac or cryopac.  This is especially important for anything that will not be reheated to a food safe temperature after thawing, as smoked fish would not be, and many leftovers that folks only want to rewarm.

[Keymaster]

I used a High mountain Brine on my last salmon Smoke. It had 3.99% Sodium Nitrite and 0.8 % sodium erythorbate, Do I have to worry about Bacteria? My salmon is Vacuum packed, in the freezer, I thaw it in the fridge and then it goes on a plate and down the hatch very quickly.  ;D

[punchlock]

I used a High mountain Brine on my last salmon Smoke. It had 3.99% Sodium Nitrite and 0.8 % sodium erythorbate, Do I have to worry about Bacteria? My salmon is Vacuum packed, in the freezer, I thaw it in the fridge and then it goes on a plate and down the hatch very quickly.  ;D

Sounds dangerous to me Keymaster. You might be best to just send me what's left so I can dispose of the contaminated product safely.  ;) ;D

[BuyLowSellHigh]

I used a High mountain Brine on my last salmon Smoke. It had 3.99% Sodium Nitrite and 0.8 % sodium erythorbate, Do I have to worry about Bacteria? My salmon is Vacuum packed, in the freezer, I thaw it in the fridge and then it goes on a plate and down the hatch very quickly.  ;D

My only concern, from what you have described,  is the "down the hatch very quickly" part.  Don't choke.   :D   ;D

[KyNola]

You just gotta love the food police. ;)

[Caneyscud]

Exactly the reason I'm so leary of the anaerobic conditions while "wet-aging" cryovacced meats. 

[porterdriver]

Some questions regarding this thread.  I have only heard of wet-aging beef.  Does this crowd wet-age other meats as well?  Is beef as subject to Botulism as fish?  Typically, don't we cook beef to a higher temp (185+) than fish, doesn't that mitigate the botulism danger?

[precookingsmoker]

From what I just finished reading Porterdriver.....

All foods, meats and fishes are threatened equally from the varieties of C. Botulinum spores, regardless wet-aging or ANY low oxygen condition above 38 degrees F.

Different varieties of these spores are "controlled" or inhibited in growth, but NOT killed, under different conditions.

C. Botulinum spore has several types (Groups) some of which are resistant to heat.... and are not killed until temperatures go OVER 212 F.

It appears "inhibiting" the growth of C. Bot. spore is the best most of us can do, and our ability to actually destroy all C. Bot spore varieties will not occur until we have turned the meats and fishes into charcoal.

Really nasty stuff.....having deadly biological weapon capability too......

Refer to:
 
http://www.ext.colostate.edu/pubs/foodnut/09305.html
http://en.wikipedia.org/wiki/Clostridium_botulinum
etc.
-Larry

[precookingsmoker]

After adding the previous points in this discussion, it should have contained another comment.....

It is likely the greatest danger in the development of toxins produced by C.Bot spores when any form of vacuum sealing is done.........is not to ourselves......but to those we give our chilled and frozen packages to.

We do not know what temperatures the packs (now starting to de-thaw) reach after they are "tossed" in the trunk of another persons car for transport home, even if ice is used in some kind of "Cooler", nor do we know how long the packs are in their kitchens unopened and what the temperature is when they are actually opened.....

One thing seems clear. Going above 38 degrees F. allows the spores to BEGIN producing toxins. By the time the spores have reached 90 degree F. temperatures they are producing MASSIVE amounts of toxins, while still sealed in their low oxygen environment.

VIP !!!  -We risk our friends and family members if they do not understand the steps or toxin countermeasures they must take if the packages are unopened.  :-[

This likely applies to fruits too. Which I vacuum pack a lot of........

What a learning curve! ....... earning a B.S. &  B.B. (Bachelor of Smoke & Bachelor of Bugs.)

[BuyLowSellHigh]

One thing seems clear. Going above 38 degrees F. allows the spores to BEGIN producing toxins. By the time the spores have reached 90 degree F. temperatures they are producing MASSIVE amounts of toxins, while still sealed in their low oxygen environment.

The spores DO NOT produce the toxin that is the cause of botulism. Only the bacteria do that. The spores are the "seed" for bacteria.  

Cooking to food safe temperatures destroys the then active bacteria. The toxin produced by the bacteria is deactivated by heating to 176 °F for 10 minutes. The spores can survive to 250 °F. depending on strain.

Refrigeration below 38 °F keeps the bacteria and spores dormant. Cooking to food safe temps destroys the bacteria and any toxin then present. The problem comes when food products that have spores present and will not be further cooked or heated to temperatures sufficient to destroy the bacteria and toxin are held at conditions that allow the spores to germinate. Hence the concern for cooked foods (e.g., smoked fish) that will not be further cooked.

If you follow normal food handling and storage practices you should be just fine.

This is the best practical overview of botulism I know of.
http://www.ext.colostate.edu/pubs/foodnut/09305.pdf

[KyNola]

You know it's really pretty simple.  If you're that leery and concerned about the danger of vac sealing ANY food product, then simply don't do it.

[NePaSmoKer]

Ohhhhh Jeebus  :D

IN COMING  :D