# Why 4 hrs



## ak1 (Sep 8, 2010)

I'm wondering,

Why does the USDA guidelines state 4 hrs to go from 40 deg to 140 deg.

I checked Health Canada, and all they say is to cook to safe temperature. So I called and was told that as long as the food gets to the safe temperature in a reasonable amount of time it will be fine.

So I'm wondering? Is there a reason why USDA guidelines state 4 hrs?


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## richoso1 (Sep 8, 2010)

You might try contacting the USDA directly. At least you'd get the answer straight from the source.

http://www.usda.gov/wps/portal/usda/usdahome?navtype=MA&navid=CONTACT_US


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## Bearcarver (Sep 8, 2010)

Health Canada: "Safe Temp in a reasonable amount of time?"

Now there's some accuracy for ya!

Do the speed limit signs in Canada say, "Please Drive At Safe & Reasonable Speeds"?

I would think may scientists have spent many hours with many meats, with many probes, at many temps, and came up with the  minimum temp & time to smoke cook meats, because of people like us, who want to make meat as good tasting as possible, but still safe to eat.

Bearcarver


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## princess (Sep 8, 2010)

WAIT WAIT!!! I know this one!!  This is all that fermentation stuff I have been studying!!

It has everything to do with microbiology and the rate at which bacteria multiply and are able to make spores that can be heat resistant!!  ::cheer::

But.. I am at work and won't have time to REALLY reply to this until later. :)

Super-nerd to the rescue!

-Princess


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## brdprey (Sep 8, 2010)

(searches for nerd spit proof cover to apply on ones self for later)


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## erain (Sep 8, 2010)

Princess said:


> WAIT WAIT!!! I know this one!!  This is all that fermentation stuff I have been studying!!
> 
> It has everything to do with microbiology and the rate at which bacteria multiply and are able to make spores that can be heat resistant!!  ::cheer::
> 
> ...


Super nerd has it right on, and as time passes the rate the nasties multiply get to a point where they become unmanagable hence the 4 hour  40-140 degree time/temp lines...


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## stircrazy (Sep 8, 2010)

AK1 said:


> I'm wondering,
> 
> Why does the USDA guidelines state 4 hrs to go from 40 deg to 140 deg.
> 
> ...


Its simple, we in Canada are reasonable and don't realy try to push the envalope, in the US if they didn't put a specific time there are less than desiriable resturants that would try to push there luck.  not saying that there arn't in Canada also, just not as much.  and Canada, not being as driven to sue, there isn't as much push to have exact numbers that can protect al restuarant from lawsuits as well.

the multiplication of bacterial isn't linier between 40 and 140, the 4 hour bacteria multiplication is based off a specific temp, and most bacteria only have a 30 degree growth range, so the 40 to 140 is obvoulsy covering several types of backteria with different prefered temps. 

Steve


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## arnie (Sep 8, 2010)

Now you know


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## ak1 (Sep 8, 2010)

richoso1 said:


> You might try contacting the USDA directly. At least you'd get the answer straight from the source.
> 
> http://www.usda.gov/wps/portal/usda/usdahome?navtype=MA&navid=CONTACT_US


Did it! Ended up talking to a real person, with minimal wait time.

 


Princess said:


> WAIT WAIT!!! I know this one!!  This is all that fermentation stuff I have been studying!!
> 
> It has everything to do with microbiology and the rate at which bacteria multiply and are able to make spores that can be heat resistant!!  ::cheer::
> 
> ...


That's pretty well it. The issue isn't so much the bacteria, but the toxic byproducts they produce. The 4 hr rule minimizes the amount of those toxins that are produced. However I was told there is a bit of a leeway (15-20 mins). If you go much longer than 4 hrs to hit 140, then although the vast majority of the bacteria are killed, there could be an unhealthy amount of toxins still present.

 


Bearcarver said:


> Health Canada: "Safe Temp in a reasonable amount of time?"
> 
> Now there's some accuracy for ya!
> 
> ...


I know! I thought the same. But then again, the person I talked to didn't seem very knowledgeable. Digging through the website all I could find was that food should be in the danger zone for no more than 2 hrs. I realize that there are differences between USDA & Health Canada guidelines. That's why I keep trying to find the reasoning behind the rules.


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## Bearcarver (Sep 8, 2010)

I look at it this way, in this particular instance:

A lot of much more knowledgable people than I study this stuff. They come up with safety guidelines. I go by their guide, because they know more about it than I do. I don't have the time, the resources, or the inclination to be able to dispute their findings.

I warn others who don't know about those guidelines. They can then follow those rules or not follow them. If they tell others those rules are stupid, I dispute that, because I don't want people who know less than those who made the rules to confuse people into getting sick or dying.

Simple as that,

Bear


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## mballi3011 (Sep 8, 2010)

I'm with Rich on this one. He knows his poo poo.


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## princess (Sep 8, 2010)

I totally agree with you, Bearcarver. But I am also like a four year old whose favorite questions is WHY?!?  Not because I'm going to disparage it or try to push my limits of safety, but because I think Science is Cool and understanding how stuff works is key to ensuring success down the road. (and I am a total nerd...)

So: bacteria 101

It's all about optimal environment. Ther are only a few ways to STOP bacteria from growing:

Raise the temperature

Drop the pH

Remove the moisture

Do *any* of those three and you halt bacterial growth. (This is why vinegar never goes bad and why dried onions last forever.)  You would not want to hold meat at low temperatures for THE EXACT same reason you wouldn't eat potato salad that's been out on the counter all day.  If you hold any food at optimal temps (with moisture present and without an acidic environment) the pathogenic bacteria will swiftly outnumber the beneficial bacteria and make you VERY sick.  As was mentioned before, once those toxins are present, there is no way to remove them.

Think of this: If I handed you a grey slimy piece of rotted meat, no amount of cooking is going to make it safe. :P

At the middling temps that most of us prefer to smoke at, bacteria have a field day, multiplying faster than ever before. It's dark, warm, wet & meaty. This is why meat on a countertop rots faster than meat in your fridge, or meat in your freezer. At *every five degrees above freezing, some bacteria multiply twice as fast as they did before. *

So for example, if Bacteria A doubles every 36 hours at 32 degrees, then it doubles every 16 hours at 37 degrees. it doubles every 8 hours at 42 degrees. Every 4 hours at 47 degrees. Every 2 hours at 52 degrees. Every hour at 57 degrees. Every 30 minutes at 62 degrees. Every 15 minutes at 67 degrees. Every 7.5 minutes at 73 degrees. Every 3.75 minutes at 78 degrees. Every 112 seconds at 83 degrees. Every minute at 88. Every 30 seconds at 93... You see where this is going? If you hold meat above 40 degrees and under 140, you are creating the perfect environment for pathogenic bacterial growth.. aka ROTTING.

This is ALSO why operating rooms are so cold, why fermented beer was safer than drinking water in the Middle Ages, why yogurt lasts longer than milk, why pickles never seem to go bad as fast as raw cucumbers, why we brush sliced apples with lemon juice to keep them from turning brown, why high pressure canning works so darn well, why you should be SO DILIGENT about keeping your meat prep area CLEAN and ICY... So much comes back to this exact answer.

It is all about controlling the BAD bacteria and encouraging the GOOD bacteria.

Wanna hear some more geek? Ask away!! :)

Cheers!

-Princess


Bearcarver said:


> I look at it this way, in this particular instance:
> 
> A lot of much more knowledgable people than I study this stuff. They come up with safety guidelines. I go by their guide, because they know more about it than I do. I don't have the time, the resources, or the inclination to be able to dispute their findings.
> 
> ...


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## meateater (Sep 8, 2010)

So 40* to 140* in 4 hours it is.


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## kcbluesnbbq (Sep 8, 2010)

Princess, that is my kind of answer. Everybody says I explain to much when they ask me why. I am like you, have to know why, why, why.

Thanks for passing that along.


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## bbally (Sep 8, 2010)

Bacteria mutliply very rapidly at temperatures between 40 F and 140 F.  The studies clearly show that dangerous levels of colony size can start to be a real problem after four hours of incubation time.

Canada has a lower limit on food in the unsafe zone.  The third bullet point is directly from the Canadian Food Inspection site and their food safety manual.
[h2]CHILL[/h2]
Bacteria can grow in the danger zone between 4°C and 60°C (40°F to 140°F).
To prevent the growth of harmful bacteria, keep cold food cold. Store it at or below 4°C (40°F).
Do not keep food in the danger zone for longer than two hours. Foods that need to be refrigerated or frozen should be stored immediately after they are brought home from the grocery store.
Refrigeration at or below 4°C (40°F) slows down most bacterial growth, while freezing at or below -18°C (0°F) can stop bacteria growth completely. (But remember: refrigeration and freezing won't kill bacteria. Only proper cooking will do that!)
Plan ahead: thaw food in the refrigerator, where the food will stay at a safe, constant temperature of 4°C (40°F) or below.
*WHY?* Disease-causing bacteria multiply quickly when food is kept at room temperature.

Canadian Food Link


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## pineywoods (Sep 8, 2010)

meateater said:


> So 40* to 140* in 4 hours it is.


Actually they changed it to 41-135 in under 4 hours for punctured meat. But I gotta say 40-140 in under 4 is easier to remember

Also remember there is the intact muscle rule and that only requires the outer 1/2" pass the 140 (maybe 135 now)  mark in under 4 hours


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## princess (Sep 8, 2010)

I don't know very many people that have thermometers carefully calibrated enough to truly feel confident in the difference between 40 and 41 degrees anyway, you know?  But then, I deal mostly with sausage, and WHOA do sausage makers increase the risk for contamination.

-Princess


Pineywoods said:


> Actually they changed it to 41-135 in under 4 hours for punctured meat. But I gotta say 40-140 in under 4 is easier to remember
> 
> Also remember there is the intact muscle rule and that only requires the outer 1/2" pass the 140 (maybe 135 now)  mark in under 4 hours


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## stircrazy (Sep 8, 2010)

one thing I found out while looking up info on bacteria, is that a bacteria will only grow in a controled 30 degree range either side of the optimum temp, most of the nasty natural occuring ones in meat have the mid point of that range at 98 degrees, so they will multiply anywhere from 68 degrees to 128 degrees.  problem is the main ones that realy nail our coffin lids are the ones that we introduce by handling the meat.  and they have different mid points so hence the wider operating range.   but most bacteria that is already present in meat will be a body temp one.

take e-coli for example.  the one that is responcable for the 3rd largest numbers of sicknesses in food, will only grow in that 30 degree range around body temp, and cooking to an internal temp of 140 fot 1 hour ot 167 for 10 min will destroy the bacteria and the toxin.  also if it is in normal O2 levels it will not grow.  so on your counter it wont grow, but as soon as you put it into your smoker the enviorment is now O2 depleated and away it goes.  also wraped food on the counter is a good enviorment for this bacteria. 

Steve


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## scarbelly (Sep 8, 2010)

Great thread and folks stepping up with well researched answers

Thanks for all of you taking the time to do the research and answer with facts


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## princess (Sep 8, 2010)

Hi stircrazy. Wow, I'm a little intimidated... you've been a member for nearly a year and have 100's of posts. You have me at the disadvantage, as I am quite a rookie here.  But this stuff? *IS* my forte, and is part of why I joined this forum, so I wanted to speak up one last time.

I don't know you personally, so please don't take what I am about to say that way, okay?  
	

	
	
		
		



		
		
	


	





   I'm just concerned because I feel like a PART of what you are saying is a bit misleading. .

The part I am most concerned with is that statement that "most bacteria that is already present in meat will be a body temp one."  I would like to see the data for that statement, as it is totally inconsistent with my (limited, admittedly) knowledge of microbiology. Optimal temps means growing at the fastest rate, outside of optimal just means SLOWER, it doesn't mean stop. I could also be totally misunderstanding you...

_e.coli_ is the least of my worries when compared to _bacillus cereus_.  _B.cereus_ spores can live WAY longer and at higher temperatures than _e.coli_. B.cereus is THE LEADING CAUSE of food poisoning in the United States. The only reliable way to destroy_ b.cereus_ toxin is to hold the meat at 259°F for more than 90 minutes. So, as meat handlers, we need to do EVERYTHING we can to ensure that as little as possible of the odorless, tasteless toxin from this terribly resistant bacteria gets produced.

https://edis.ifas.ufl.edu/pdffiles/FS/FS10300.pdf  is a great resource for this...

At this point, I think it may be prudent for me to step away from this thread. I get pretty passionate about food safety and don't want to get so hopped up on this topic that I begin to forget my manners. I am still very new here, truly a guest in all y'alls house, and I don't want to over-geek my welcome. If anyone personally has questions about micro-biology and/or food illness, I encourage you to send me a PM.

Cheers!!

-Princess


stircrazy said:


> one thing I found out while looking up info on bacteria, is that a bacteria will only grow in a controled 30 degree range either side of the optimum temp, most of the nasty natural occuring ones in meat have the mid point of that range at 98 degrees, so they will multiply anywhere from 68 degrees to 128 degrees.  problem is the main ones that realy nail our coffin lids are the ones that we introduce by handling the meat.  and they have different mid points so hence the wider operating range.   but most bacteria that is already present in meat will be a body temp one.
> 
> take e-coli for example.  the one that is responcable for the 3rd largest numbers of sicknesses in food, will only grow in that 30 degree range around body temp, and cooking to an internal temp of 140 fot 1 hour ot 167 for 10 min will destroy the bacteria and the toxin.  also if it is in normal O2 levels it will not grow.  so on your counter it wont grow, but as soon as you put it into your smoker the enviorment is now O2 depleated and away it goes.  also wraped food on the counter is a good enviorment for this bacteria.
> 
> Steve


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## Bearcarver (Sep 9, 2010)

LOL,

This doesn't go directly to anyone, but just general:

After all the research we all have done, some a lot more than others
It all comes down to what?

Like I said in the beginning:

Get your food from 40˚ to 140˚ (or maybe 135˚) in no longer than 4 hours.

That and keeping everything in the area as sterile as possible (including yourself) should keep you safe.

Knowing who found this out, why they found it out, when they found it out, and how they found it out does nothing to change the facts we all must know
*[color= rgb(24, 24, 24)]Get your food from 40˚ to 140˚ (or maybe 135˚) in no longer than 4 hours.[/color]*

I can't rattle off all the information I found when I did most of my searching long ago, because I don't remember how many bad little guys double their population in how many seconds, because it was too long ago when I read it.

I stopped reading and started smoking when I realized that no matter how much info you cram into your head, while you could be curing and/or smoking delicious meats, the fact remains, all you really have to know is:

*Get your food from 40˚ to 140˚ (or maybe 135˚) in no longer than 4 hours.*

That and:

*Get your food from 40˚ to 140˚ (or maybe 135˚) in no longer than 4 hours.*

Bear

PS: To admins---Those two stupid lines were added by the platform. I tired of removing them & left these there.


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## arnie (Sep 9, 2010)

Well said, Princess, more information than I want, but well said.  
	

	
	
		
		



		
			






I am glad we have people who take a dedicated interest in food safety.

Me? I’m too squeamish. If I thought about it too long I’d turn vegetarian.  
	

	
	
		
		



		
		
	


	





Then I’d find out that’s just as bad and stop eating.

I have worked long and hard to bulk up my frame and while I could stand a little trimming down there’s no need to go overboard.


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## princess (Sep 9, 2010)

I love you, Bear. :)  Remind Mrs. BC what a good dude she has.

-Princess
 


> Knowing who found this out, why they found it out, when they found it out, and how they found it out does nothing to change the facts we all must know
> *Get your food from 40˚ to 140˚ (or maybe 135˚) in no longer than 4 hours.*


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## alelover (Sep 9, 2010)

259°F for more than 90 minutes? Shouldn't it be 159? Seems like the meat would be inedible at that temp.


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## Dutch (Sep 9, 2010)

Okay-before this thread starts to head down hill any further than it has, let me remind everyone that this is intended to be an enlightening and interesting discussion and that everyone is entitled their own opinion. Let's not belittle someone because their opinion is different than yours. If this continues, this thread will be removed.


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## scarbelly (Sep 9, 2010)

Thanks Dutch !!


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## chefrob (Sep 9, 2010)

Bearcarver said:


> *[color= rgb(24,24,24)]Get your food from 40˚ to 140˚ (or maybe 135˚) in no longer than 4 hours.[/color]*


i'm with bear.............it's worked for me for the last 25+ yrs in food service.

i do want to say these types of discussions are good to have for a couple of reasons. it gets people to do some research on there own, it lets us have a healthy exchange about good vs. bad food handling practices, and last but not least it puts out info to those who might not post but do read these things.............


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## princess (Sep 10, 2010)

It is, you're absolutely right, and thats my point!! Good eyes, alelover!  You have to keep that *TOXIN* from showing up in your meat. _B.cereus _itself is kinda nasty, but it is the toxin produced as it multiplies that is what makes you sick, and it is practically impossible to get rid of once you have it.

So, to re-iterate:

40-140 in 4

(and once it's cooked, eat it or fridge it)


alelover said:


> 259°F for more than 90 minutes? Shouldn't it be 159? Seems like the meat would be inedible at that temp.


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## tjohnson (Sep 18, 2010)

If you've ever had "Food Poisoning", you'll do everything to NOT get it again!!!

The United States has the "SAFEST" food supply in the entire world, mostly because our Government's Intervention.

Todd


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## beer-b-q (Sep 18, 2010)

Bearcarver said:


> LOL,
> 
> This doesn't go directly to anyone, but just general:
> 
> ...


I agree with Bear...


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## pandemonium (Sep 18, 2010)

Let me ask this,are these bacterias always present in every piece of meat? and have to be killed by cooking? or like salmonella where as far as I know is

not in every piece of chicken, so eating a raw piece of chicken wont necessarily make you sick.


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## Bearcarver (Sep 18, 2010)

pandemonium said:


> Let me ask this,are these bacterias always present in every piece of meat? and have to be killed by cooking? or like salmonella where as far as I know is
> 
> not in every piece of chicken, so eating a raw piece of chicken wont necessarily make you sick.


Short answer to bacteria on all meat----Yes, some good, some bad.

More:

http://www.newton.dep.anl.gov/askasci/mole00/mole00035.htm

AND

http://bacteriamuseum.org/cms/Food-And-Water-Safety/food-safety.html

BTW: I wouldn't eat any raw chicken, or any other raw meat.

*Did I mention?Get your food from 40˚ to 140˚ (or maybe 135˚) in no longer than 4 hours.*

Bear


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## gnubee (Sep 18, 2010)

Does anyone know what effect removing all the air from the meat has in preserving it. Eg. using a vacuum bagger. Or does that just speak to eliminating freezer burn and have no effect on the growth of the little nasty bugs.

I have found that placing tiny little signs on the surface of the meat that read " Please Keep off the meat " to be totally ineffective as it appears that germs and virus don't know how to read.

As a consequence I now cooke my meats to 140 or more in under 4 hours.

Ps . Maybe its just me but I find meats like ground beef, or ground pork that have been left out on the counter for an hour or so before frying or grilling do not seem to taste as good as meats taken cold from the package shaped immediately into patties and slapped directly on the pan or grill. Ergo I think the more time that germs act upon the meat the more they seem to degrade the taste quality. Perhaps that is just my imagination.  My wife likes to have meat come to room temp before she cooks it. Not me.

Tip. Try this in your local supermarket. Look closely at a piece of  pork, beef or chicken sitting in the meat cooler. Pick up the package and go to a different part of the store then look closely at it again.

In many stores the type of lighting is very different in each section. You may now detect a greenish blue tinge to the meat that isn't apparent under the red hued blue/green suppressed light from the meat section of the store. This is usually more dectectable in pork and chicken than beef.  Sometimes there is little or no difference, sometimes there is a huge difference. 

If you get home and open the package of ground beef then break open a piece to make Burger patties for example. You may now notice an outside narrow layer of nicely red colored beef while in contrast the bulk of the center of the meat is a dull greyish. In all probability the meat surface  has been either colored with some bright red colouring or the center portion may have been covered with a thin layer of fresher better looking meat. That greyish tinge is caused by bacteria. Lots more of it than the fresher outer coating would suggest.

If you detect this kind of practice don't be afraid to complain and then go ot look for a better place to shop for meat where these kind of practices don't occur.

I am now officially off my soap box.


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## tjohnson (Sep 18, 2010)

Nice looking Soap Box!

TJ


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## beer-b-q (Sep 19, 2010)

*Nice Soap Box GnuBee,  *

Where you Been?

I haven't seen you around, or do I need to get my glasses changed again?


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## Bearcarver (Sep 19, 2010)

GnuBee said:


> Does anyone know what effect removing all the air from the meat has in preserving it. Eg. using a vacuum bagger. Or does that just speak to eliminating freezer burn and have no effect on the growth of the little nasty bugs.
> 
> I have found that placing tiny little signs on the surface of the meat that read " Please Keep off the meat " to be totally ineffective as it appears that germs and virus don't know how to read.
> 
> ...


Germs could be like cats. The "Keep Off" signs on our counter tops don't work either. Doesn't mean he can't read. He just doesn't obey. We yell at him when he jumps up on the counters, but he keeps doing it---Doesn't mean he's deaf.

Interesting thing about the lights.

Outside color on ground beef
Could it be a light sprinkle of "cure"?
Good to see you again,

Bear


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## smokinstevo27 (Sep 19, 2010)

stircrazy said:


> Its simple, we in Canada are reasonable and don't realy try to push the envalope, in the US if they didn't put a specific time there are less than desiriable resturants that would try to push there luck.  not saying that there arn't in Canada also, just not as much.  and Canada, not being as driven to sue, there isn't as much push to have exact numbers that can protect al restuarant from lawsuits as well.
> 
> the multiplication of bacterial isn't linier between 40 and 140, the 4 hour bacteria multiplication is based off a specific temp, and most bacteria only have a 30 degree growth range, so the 40 to 140 is obvoulsy covering several types of backteria with different prefered temps.
> 
> Steve


What is this guy talking aboot, eh? You are on a sight comprised mostly of Americans. What is with the generalized insults? And your spelling leaves a bit to be desired. This country sets the standards for the rest of the world in most facets of life. Our country has funded more research on BAKTERIA in a year than Canada.


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## princess (Sep 20, 2010)

Removing air can help, but not all bacteria and not all the time. In fact, some of the ickiest nastiest bacteria out there are totally content to multiply in an anaerobic environment.  I like the sign idea though!! ;) Let me know if you get that working!!

The presence of a grey *internal core *on ground meat is not uncommon nor is it a "bad" thing, and I have mixed thoughts on it.  The greying meat is NOT toxic, and is not caused by bacterial activity. It is caused by a lack of oxidation, or not enough exposure to air.  (You need the myoglobins naturally found in the meat to react with oxygen to get that deep red color) As Americans we are "more likely to buy" produce and meats that we find attractive, and the stores know this, so they let the meat air out a bit before they package it AND use thin clingfilm that allows oxygen to penetrate to the surface. Sometimes, they spray it with a quick blast of oxygen before packing it.

So, if I have more grey meat on the inside than you do, my meat may actually be more fresh.

(Not talking about outside greying here, that's a different song...)

So... I belong to Club Grind Yer Own.  Esp now that I have my schmaltzy new grinder.

Cheers!

Princess

http://www.fsis.usda.gov/factsheets/ground_beef_and_food_safety/index.asp


GnuBee said:


> Does anyone know what effect removing all the air from the meat has in preserving it. Eg. using a vacuum bagger. Or does that just speak to eliminating freezer burn and have no effect on the growth of the little nasty bugs.
> 
> I have found that placing tiny little signs on the surface of the meat that read " Please Keep off the meat " to be totally ineffective as it appears that germs and virus don't know how to read.
> 
> ...


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## stircrazy (Sep 20, 2010)

smokinstevo27 said:


> What is this guy talking aboot, eh? You are on a sight comprised mostly of Americans. What is with the generalized insults? And your spelling leaves a bit to be desired. This country sets the standards for the rest of the world in most facets of life. Our country has funded more research on BAKTERIA in a year than Canada.


well that was typical and expected.  actually there were no insults there, just pointing out that the US is more of a litigation society than Canada, although we are getting better 
	

	
	
		
		



		
		
	


	





.

By putting exact numbers in the regulations it allows restaurants a bit of protection if they follow the guidelines.  say take Jack in The Box for example.  if they had been following proper cooking procedures would they have lost as much money as they did from law suits? 

and if you look at standards in the world, trust me the US standards are not seen anywhere except US countries.  every country has there own standards good or bad, just how it is, and a lot of them are more stringent is some ways and less stringent in others.  Canada's standards are very similar to the US, some times we adopt things before the US sometimes we adopt after the US, really the only thing different between the US and Canada, is it is cheaper to live in the US, and we get more snow..  Oh and we don't have Jack in the Box and I am dieing for a sour dough jack right now...  
	

	
	
		
		



		
		
	


	





Steve


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## nwdave (Sep 20, 2010)

I've learned so much in this thread, I've got a headache, but it's a good headache.  I want to point out to PRINCESS, that just because you might be the new kid on the block does not mean your contribution or opinion is without value.  Actually, I think it stands heads and shoulders above some who don't listen and just keep repeating the same misleading tripe.  I'm with BearCarver in having learned some of this way back when, but since the field of knowledge in smoking is so broad, there's only so much time to learn all of the skills required to become successful.  Oh, and I really love your use of technical terms:  ickiest, nastiest bacteria.
	

	
	
		
		



		
		
	


	





   Now there's a quote to live by.  Hey, we're smiling. 
	

	
	
		
		



		
		
	


	





   Now when I'm asked why the guideline, I can point to your contribution as an excellent source.  Please, please feel free to step in with your expertise.  We all contribute to the well being of this site by the sharing of our composite knowledge, and I personally have never been afraid to learn something new from the "new kid on the block".  We were all new to this site at one time.  Oh, and don't you just the love the taste of fresh home ground beef?  At least now I know what's in the ground beef.

Now, what was BC saying about 40 to 140 in no more than 4?  Sounds like something that could be made into a high school cheer leaders mantra. Some of the best guidelines that are easily remembered are the ones presented in the simplest of terms.  Gotta love it.


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## ak1 (Sep 8, 2010)

I'm wondering,

Why does the USDA guidelines state 4 hrs to go from 40 deg to 140 deg.

I checked Health Canada, and all they say is to cook to safe temperature. So I called and was told that as long as the food gets to the safe temperature in a reasonable amount of time it will be fine.

So I'm wondering? Is there a reason why USDA guidelines state 4 hrs?


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## richoso1 (Sep 8, 2010)

You might try contacting the USDA directly. At least you'd get the answer straight from the source.

http://www.usda.gov/wps/portal/usda/usdahome?navtype=MA&navid=CONTACT_US


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## Bearcarver (Sep 8, 2010)

Health Canada: "Safe Temp in a reasonable amount of time?"

Now there's some accuracy for ya!

Do the speed limit signs in Canada say, "Please Drive At Safe & Reasonable Speeds"?

I would think may scientists have spent many hours with many meats, with many probes, at many temps, and came up with the  minimum temp & time to smoke cook meats, because of people like us, who want to make meat as good tasting as possible, but still safe to eat.

Bearcarver


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## princess (Sep 8, 2010)

WAIT WAIT!!! I know this one!!  This is all that fermentation stuff I have been studying!!

It has everything to do with microbiology and the rate at which bacteria multiply and are able to make spores that can be heat resistant!!  ::cheer::

But.. I am at work and won't have time to REALLY reply to this until later. :)

Super-nerd to the rescue!

-Princess


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## brdprey (Sep 8, 2010)

(searches for nerd spit proof cover to apply on ones self for later)


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## erain (Sep 8, 2010)

Princess said:


> WAIT WAIT!!! I know this one!!  This is all that fermentation stuff I have been studying!!
> 
> It has everything to do with microbiology and the rate at which bacteria multiply and are able to make spores that can be heat resistant!!  ::cheer::
> 
> ...


Super nerd has it right on, and as time passes the rate the nasties multiply get to a point where they become unmanagable hence the 4 hour  40-140 degree time/temp lines...


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## stircrazy (Sep 8, 2010)

AK1 said:


> I'm wondering,
> 
> Why does the USDA guidelines state 4 hrs to go from 40 deg to 140 deg.
> 
> ...


Its simple, we in Canada are reasonable and don't realy try to push the envalope, in the US if they didn't put a specific time there are less than desiriable resturants that would try to push there luck.  not saying that there arn't in Canada also, just not as much.  and Canada, not being as driven to sue, there isn't as much push to have exact numbers that can protect al restuarant from lawsuits as well.

the multiplication of bacterial isn't linier between 40 and 140, the 4 hour bacteria multiplication is based off a specific temp, and most bacteria only have a 30 degree growth range, so the 40 to 140 is obvoulsy covering several types of backteria with different prefered temps. 

Steve


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## arnie (Sep 8, 2010)

Now you know


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## ak1 (Sep 8, 2010)

richoso1 said:


> You might try contacting the USDA directly. At least you'd get the answer straight from the source.
> 
> http://www.usda.gov/wps/portal/usda/usdahome?navtype=MA&navid=CONTACT_US


Did it! Ended up talking to a real person, with minimal wait time.

 


Princess said:


> WAIT WAIT!!! I know this one!!  This is all that fermentation stuff I have been studying!!
> 
> It has everything to do with microbiology and the rate at which bacteria multiply and are able to make spores that can be heat resistant!!  ::cheer::
> 
> ...


That's pretty well it. The issue isn't so much the bacteria, but the toxic byproducts they produce. The 4 hr rule minimizes the amount of those toxins that are produced. However I was told there is a bit of a leeway (15-20 mins). If you go much longer than 4 hrs to hit 140, then although the vast majority of the bacteria are killed, there could be an unhealthy amount of toxins still present.

 


Bearcarver said:


> Health Canada: "Safe Temp in a reasonable amount of time?"
> 
> Now there's some accuracy for ya!
> 
> ...


I know! I thought the same. But then again, the person I talked to didn't seem very knowledgeable. Digging through the website all I could find was that food should be in the danger zone for no more than 2 hrs. I realize that there are differences between USDA & Health Canada guidelines. That's why I keep trying to find the reasoning behind the rules.


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## Bearcarver (Sep 8, 2010)

I look at it this way, in this particular instance:

A lot of much more knowledgable people than I study this stuff. They come up with safety guidelines. I go by their guide, because they know more about it than I do. I don't have the time, the resources, or the inclination to be able to dispute their findings.

I warn others who don't know about those guidelines. They can then follow those rules or not follow them. If they tell others those rules are stupid, I dispute that, because I don't want people who know less than those who made the rules to confuse people into getting sick or dying.

Simple as that,

Bear


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## mballi3011 (Sep 8, 2010)

I'm with Rich on this one. He knows his poo poo.


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## princess (Sep 8, 2010)

I totally agree with you, Bearcarver. But I am also like a four year old whose favorite questions is WHY?!?  Not because I'm going to disparage it or try to push my limits of safety, but because I think Science is Cool and understanding how stuff works is key to ensuring success down the road. (and I am a total nerd...)

So: bacteria 101

It's all about optimal environment. Ther are only a few ways to STOP bacteria from growing:

Raise the temperature

Drop the pH

Remove the moisture

Do *any* of those three and you halt bacterial growth. (This is why vinegar never goes bad and why dried onions last forever.)  You would not want to hold meat at low temperatures for THE EXACT same reason you wouldn't eat potato salad that's been out on the counter all day.  If you hold any food at optimal temps (with moisture present and without an acidic environment) the pathogenic bacteria will swiftly outnumber the beneficial bacteria and make you VERY sick.  As was mentioned before, once those toxins are present, there is no way to remove them.

Think of this: If I handed you a grey slimy piece of rotted meat, no amount of cooking is going to make it safe. :P

At the middling temps that most of us prefer to smoke at, bacteria have a field day, multiplying faster than ever before. It's dark, warm, wet & meaty. This is why meat on a countertop rots faster than meat in your fridge, or meat in your freezer. At *every five degrees above freezing, some bacteria multiply twice as fast as they did before. *

So for example, if Bacteria A doubles every 36 hours at 32 degrees, then it doubles every 16 hours at 37 degrees. it doubles every 8 hours at 42 degrees. Every 4 hours at 47 degrees. Every 2 hours at 52 degrees. Every hour at 57 degrees. Every 30 minutes at 62 degrees. Every 15 minutes at 67 degrees. Every 7.5 minutes at 73 degrees. Every 3.75 minutes at 78 degrees. Every 112 seconds at 83 degrees. Every minute at 88. Every 30 seconds at 93... You see where this is going? If you hold meat above 40 degrees and under 140, you are creating the perfect environment for pathogenic bacterial growth.. aka ROTTING.

This is ALSO why operating rooms are so cold, why fermented beer was safer than drinking water in the Middle Ages, why yogurt lasts longer than milk, why pickles never seem to go bad as fast as raw cucumbers, why we brush sliced apples with lemon juice to keep them from turning brown, why high pressure canning works so darn well, why you should be SO DILIGENT about keeping your meat prep area CLEAN and ICY... So much comes back to this exact answer.

It is all about controlling the BAD bacteria and encouraging the GOOD bacteria.

Wanna hear some more geek? Ask away!! :)

Cheers!

-Princess


Bearcarver said:


> I look at it this way, in this particular instance:
> 
> A lot of much more knowledgable people than I study this stuff. They come up with safety guidelines. I go by their guide, because they know more about it than I do. I don't have the time, the resources, or the inclination to be able to dispute their findings.
> 
> ...


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## meateater (Sep 8, 2010)

So 40* to 140* in 4 hours it is.


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## kcbluesnbbq (Sep 8, 2010)

Princess, that is my kind of answer. Everybody says I explain to much when they ask me why. I am like you, have to know why, why, why.

Thanks for passing that along.


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## bbally (Sep 8, 2010)

Bacteria mutliply very rapidly at temperatures between 40 F and 140 F.  The studies clearly show that dangerous levels of colony size can start to be a real problem after four hours of incubation time.

Canada has a lower limit on food in the unsafe zone.  The third bullet point is directly from the Canadian Food Inspection site and their food safety manual.
[h2]CHILL[/h2]
Bacteria can grow in the danger zone between 4°C and 60°C (40°F to 140°F).
To prevent the growth of harmful bacteria, keep cold food cold. Store it at or below 4°C (40°F).
Do not keep food in the danger zone for longer than two hours. Foods that need to be refrigerated or frozen should be stored immediately after they are brought home from the grocery store.
Refrigeration at or below 4°C (40°F) slows down most bacterial growth, while freezing at or below -18°C (0°F) can stop bacteria growth completely. (But remember: refrigeration and freezing won't kill bacteria. Only proper cooking will do that!)
Plan ahead: thaw food in the refrigerator, where the food will stay at a safe, constant temperature of 4°C (40°F) or below.
*WHY?* Disease-causing bacteria multiply quickly when food is kept at room temperature.

Canadian Food Link


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## pineywoods (Sep 8, 2010)

meateater said:


> So 40* to 140* in 4 hours it is.


Actually they changed it to 41-135 in under 4 hours for punctured meat. But I gotta say 40-140 in under 4 is easier to remember

Also remember there is the intact muscle rule and that only requires the outer 1/2" pass the 140 (maybe 135 now)  mark in under 4 hours


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## princess (Sep 8, 2010)

I don't know very many people that have thermometers carefully calibrated enough to truly feel confident in the difference between 40 and 41 degrees anyway, you know?  But then, I deal mostly with sausage, and WHOA do sausage makers increase the risk for contamination.

-Princess


Pineywoods said:


> Actually they changed it to 41-135 in under 4 hours for punctured meat. But I gotta say 40-140 in under 4 is easier to remember
> 
> Also remember there is the intact muscle rule and that only requires the outer 1/2" pass the 140 (maybe 135 now)  mark in under 4 hours


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## stircrazy (Sep 8, 2010)

one thing I found out while looking up info on bacteria, is that a bacteria will only grow in a controled 30 degree range either side of the optimum temp, most of the nasty natural occuring ones in meat have the mid point of that range at 98 degrees, so they will multiply anywhere from 68 degrees to 128 degrees.  problem is the main ones that realy nail our coffin lids are the ones that we introduce by handling the meat.  and they have different mid points so hence the wider operating range.   but most bacteria that is already present in meat will be a body temp one.

take e-coli for example.  the one that is responcable for the 3rd largest numbers of sicknesses in food, will only grow in that 30 degree range around body temp, and cooking to an internal temp of 140 fot 1 hour ot 167 for 10 min will destroy the bacteria and the toxin.  also if it is in normal O2 levels it will not grow.  so on your counter it wont grow, but as soon as you put it into your smoker the enviorment is now O2 depleated and away it goes.  also wraped food on the counter is a good enviorment for this bacteria. 

Steve


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## scarbelly (Sep 8, 2010)

Great thread and folks stepping up with well researched answers

Thanks for all of you taking the time to do the research and answer with facts


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## princess (Sep 8, 2010)

Hi stircrazy. Wow, I'm a little intimidated... you've been a member for nearly a year and have 100's of posts. You have me at the disadvantage, as I am quite a rookie here.  But this stuff? *IS* my forte, and is part of why I joined this forum, so I wanted to speak up one last time.

I don't know you personally, so please don't take what I am about to say that way, okay?  
	

	
	
		
		



		
		
	


	





   I'm just concerned because I feel like a PART of what you are saying is a bit misleading. .

The part I am most concerned with is that statement that "most bacteria that is already present in meat will be a body temp one."  I would like to see the data for that statement, as it is totally inconsistent with my (limited, admittedly) knowledge of microbiology. Optimal temps means growing at the fastest rate, outside of optimal just means SLOWER, it doesn't mean stop. I could also be totally misunderstanding you...

_e.coli_ is the least of my worries when compared to _bacillus cereus_.  _B.cereus_ spores can live WAY longer and at higher temperatures than _e.coli_. B.cereus is THE LEADING CAUSE of food poisoning in the United States. The only reliable way to destroy_ b.cereus_ toxin is to hold the meat at 259°F for more than 90 minutes. So, as meat handlers, we need to do EVERYTHING we can to ensure that as little as possible of the odorless, tasteless toxin from this terribly resistant bacteria gets produced.

https://edis.ifas.ufl.edu/pdffiles/FS/FS10300.pdf  is a great resource for this...

At this point, I think it may be prudent for me to step away from this thread. I get pretty passionate about food safety and don't want to get so hopped up on this topic that I begin to forget my manners. I am still very new here, truly a guest in all y'alls house, and I don't want to over-geek my welcome. If anyone personally has questions about micro-biology and/or food illness, I encourage you to send me a PM.

Cheers!!

-Princess


stircrazy said:


> one thing I found out while looking up info on bacteria, is that a bacteria will only grow in a controled 30 degree range either side of the optimum temp, most of the nasty natural occuring ones in meat have the mid point of that range at 98 degrees, so they will multiply anywhere from 68 degrees to 128 degrees.  problem is the main ones that realy nail our coffin lids are the ones that we introduce by handling the meat.  and they have different mid points so hence the wider operating range.   but most bacteria that is already present in meat will be a body temp one.
> 
> take e-coli for example.  the one that is responcable for the 3rd largest numbers of sicknesses in food, will only grow in that 30 degree range around body temp, and cooking to an internal temp of 140 fot 1 hour ot 167 for 10 min will destroy the bacteria and the toxin.  also if it is in normal O2 levels it will not grow.  so on your counter it wont grow, but as soon as you put it into your smoker the enviorment is now O2 depleated and away it goes.  also wraped food on the counter is a good enviorment for this bacteria.
> 
> Steve


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