Author Topic: Vacuum Plastic Sealing - Why No Botulism?  (Read 21310 times)

Offline WhiteSageFarms

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Vacuum Plastic Sealing - Why No Botulism?
« on: April 01, 2011, 04:17:58 AM »
Can anyone tell me why Clostridium botulinum bacteria isn't a risk for us when we vacuum pack our cheeses to age them? Logic tells me it should grow, due to the lack of oxygen in the vac'd and sealed package.

Thanks in advance for any answers!  :)

~Laurie
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Tomer1

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #1 on: April 01, 2011, 05:49:34 AM »
Leave a bit of moisture in the vaccum and put the cheese  in a hot room for a week or so to incubate and you have a good chance of growing it given you have a few viable spores.

zenith1

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #2 on: April 01, 2011, 01:29:02 PM »
probably due to both the salt and the acid environment of cheese making would be my guess.

OlJarhead

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #3 on: April 02, 2011, 02:37:42 PM »
I thought I read somewhere that botulism can't grow in a vacuum which is why (partly) we can.  Never heard of it as an issue in cheese though.

MrsKK

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #4 on: April 02, 2011, 06:22:33 PM »
Although I can't cite a source, I have to say from experience that it is the acidity of cheese that prevents botulism from growing.  That's why fruits can be canned in a hot water bath - they are high in acid - while fruits vegetables and meats need to be canned in a pressure cooker, which increases the temperature way beyond what the botulism organism needs to live and thrive.

While a hot water bath-sealed mason jar isn't exactly a vacuum, there isn't much free air in there and botulism thrives if there isn't high enough acidity.

(Modified for correction)
« Last Edit: April 03, 2011, 02:40:31 PM by MrsKK »

Sailor Con Queso

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #5 on: April 03, 2011, 01:42:51 AM »
Although rare, botulism can occur in cheeses and cheese products.

Botulism In Cheese

There currently are seven known types of Clostridium botulinum bacteria. These differ in proteolytic activity, tolerance to salt, minimum growth temperature and resistance to heat.

The proteolytic type A, B and F grow between 55 and 122 F, with most rapid growth occurring at 95F. They produce very heat-resistant spores which are a major concern in the processing of low-acid foods. They digest proteins in foods and produce a foul odor. Type A toxin is more lethal than the others, but it is a protein which is easily inactivated by heating at 180F for 10 minutes. The toxin can be absorbed into the blood stream through the digestive tract but also through respiratory mucous membranes. That means it can be contracted by inhalation as well, so don’t keep sniffing stinky spoiled food.

Inactive C. botulinum spores are commonly found in soil and water and are relatively harmless. The problem occurs when the spores germinate. As the vegetative cells grow they become overpopulated, die, and produce the deadly neurotoxin that causes botulism. Ironically, when starter bacteria die, they too release proteolytic enzymes (without the deadlt toxin).

Acid level is a primary factor. A pH near 7 favors the growth of C. botulinum, while growth is inhibited at a pH of 4.6 or lower. Note – the keyword here is “inhibited”. Slower growth means the bacteria won’t die and release toxin as quickly. Although low-acid vegetables and fish have been the chief culprits, higher-acidity foods such as tomatoes have also been involved. Inadequate processing can permit the growth of molds, yeasts or bacteria, which in turn can raise the pH enough to permit the growth of C. botulinum.

Another important condition affecting the growth of C. botulinum is the presense of oxygen. These organisms can't grow if air or free oxygen is present in their microenvironment (the area immediately next to them). This area is so small that it is not readily observed. Therefore, it is possible to have conditions develop in a food system when it appears that lots of air is available, but in reality there are areas where no air is present and anaerobic organisms, can develop.

Offline WhiteSageFarms

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #6 on: April 03, 2011, 06:52:40 AM »
Actually it's the opposite- the bacteria produces it's deadly toxin in environments devoid of oxygen, which is what vacuum packing does.  ;)

I thought I read somewhere that botulism can't grow in a vacuum which is why (partly) we can.  Never heard of it as an issue in cheese though.
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Offline WhiteSageFarms

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #7 on: April 03, 2011, 07:12:32 AM »
Thanks for the info and the link. I read the article and it's about canned cheese sauce that appears to have been left unrefrigerated for 8 days, and possibly contaminated by some potatoes that were processed near the cheese sauce...  I'm still searching for an answer- now that I think of it, there's a Food Science professor who is sitting in on the Meat Science class I'm in, so I think I'll hit him up for some answers on Monday. He's from Washington State University and is involved with the creamery there. They produce an awesome cheddar cheese that's vacuum packed into cans, which sounds awful, but it's devine. It originated at the onset of WW2, when the manager of the creamery wanted to send cheese to the troops. It's so good that it's still produced the same way today. It's named "Cougar Gold."  I have a good feeling that he'll have an answer, I'll post it when I find out.

I appreciate the info you posted, it's really pretty interesting stuff. Scarey, but interesting.

~Laurie

Although rare, botulism can occur in cheeses and cheese products.

Botulism In Cheese

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linuxboy

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #8 on: April 03, 2011, 07:39:19 AM »
It's an easy answer made complicated by bacteriology in general and dairy science and contamination specifically. To put it simply, the combination of raw material, handling, bacterial ecosystem, and affinage make it difficult for botulism spores to gain a foothold and to grow.

Botulism requires a nutrient-rich medium, one in which it can move, and one that has good conditions. Those good conditions are a low salt content, a high pH, and proper temp. Cheese matches few of these, and moreover, cheese bacteria tend to outcompete botulism.

For example, during the initial stage, when milk is fresh, those lactic bacteria multiply so quickly that botulism never gets a chance. And if it did get a chance, the acidity becomes low rather quickly. And then after the acidity, there's the salt. Botulism is inhibited at 4-6%, and I'm talking about pretty drastic inhibition.

Then after that you're stuck with a pretty solid block of protein and fat. If botulism is inside, it has little food. It's not like soup or processed cheese. And it can't move to find food.

And then suppose you have spores on the surface due to post-make contamination. If you do that, ok, then there's a chance. Except not. What would they eat? Nothing, the rind is dry. And it has all sorts of bacteria and molds on it, and yeast, even when vacuum packed. And then you have the affinage. After a couple of months, it's not really an issue anyway. And the botulism can't ever make enough toxin to be a real issue. In washed rind cheeses, it's possible, except in classic washed rind, you have many generations of bacteria that kill spores. b linens, S xylosum, etc.

So there you have it. If you approach it from a HACCP point of view in terms of the contamination vectors, it's tough to contaminate. Even if you do contaminate, there's so much stacked against botulism that it can't grow. It's not simple, you can't just say, just because the environment is anaerobic, botulism will grow, or because the pH is a certain level, it won't grow. You have to look at the bacterial ecosystem, the media, and everything else, to make a determination of risk vector and threat probability.
« Last Edit: April 03, 2011, 08:03:13 AM by linuxboy »

MrsKK

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #9 on: April 03, 2011, 02:47:02 PM »
Brian - I modified my post with the verbage that I intended...

Linuxboy, are you truly human?  When I read your posts, it amazes me how much information you have stored in your databanks! 

All in good fun - I certainly don't want to miff you!

OlJarhead

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #10 on: April 03, 2011, 03:05:00 PM »
Brian - I modified my post with the verbage that I intended...

Linuxboy, are you truly human?  When I read your posts, it amazes me how much information you have stored in your databanks! 

All in good fun - I certainly don't want to miff you!

Agreed 100%

Didn't you say you taught cheese making in WA?  If so perhaps I need to take a field trip! ;)

tananaBrian

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #11 on: April 03, 2011, 03:11:34 PM »
Linuxboy, are you truly human?  When I read your posts, it amazes me how much information you have stored in your databanks! 
Agreed 100%
Didn't you say you taught cheese making in WA?  If so perhaps I need to take a field trip! ;)

If LB wrote a book, I'd be all over it like brie on a cracker...

Brian

Offline ArnaudForestier

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #12 on: April 03, 2011, 03:26:14 PM »

If LB wrote a book, I'd be all over it like brie on a cracker...

Brian

Methinks, let's all keep our spreading knives ready...
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OlJarhead

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #13 on: April 03, 2011, 03:32:28 PM »

If LB wrote a book, I'd be all over it like brie on a cracker...

Brian

Methinks, let's all keep our spreading knives ready...

What a grand idea!  LB? 

Offline ArnaudForestier

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Re: Vacuum Plastic Sealing - Why No Botulism?
« Reply #14 on: April 03, 2011, 03:40:12 PM »
Aw, come on, folks...it's really not a big deal.  Just grab every scientific, cultural and historical text, likely, related to dairy, husbandry and cheese making, retain it fully after a cursory first run, and implement and improve upon it in an energy output rivaling Rabelais's Gargantua and Pantagruel, and you, too, can opine on anything known to turophilic mankind - as easily as if it were rudimentary and ubiquitous knowledge. ;D
- Paul