Bacteria in curing

[saucisson]

I hope Lee will correct me if I'm wrong but I suspect our micrococci are facultative anaerobes. That is they prefer oxygen but can use other substances if they have to. In this case it may well be the conversion of NO3 to NO2 and then NO releasing oxygen for other metabolic processes that allows them to survive oxygen free.

Why they aren't killed off by the osmotic shock of the salt has been puzzling me too. Of course if they are in the meat rather than just on the surface the salinity in there is only going to be what 2 or 3% maximum and they can probably survive that.

Dave

[Lee]

I hope Lee will correct me if I'm wrong but I suspect our micrococci are facultative anaerobes. That is they prefer oxygen but can use other substances if they have to. In this case it may well be the conversion of NO3 to NO2 and then NO releasing oxygen for other metabolic processes that allows them to survive oxygen free.

Why they aren't killed off by the osmotic shock of the salt has been puzzling me too. Of course if they are in the meat rather than just on the surface the salinity in there is only going to be what 2 or 3% maximum and they can probably survive that.

Dave

To be honest, I'd have to look that up, it's been a while
You're spot on with the salinity though, the brine may be 15%, but the meat ain't.
It could be the nitrate/nitrate works faster than the salinity enters the meat, so it knocks out the bad boys before they get a chance to multiply
Don't know my recipes as well as you guys, but could the nitrate/nitrite just be in there for flavour and colour rather than actually doing a bacteriocidal job

[Wohoki]

For what it's worth, I'm minded to believe that the main function of the curing salts is to give the meat the right colour. Possibly a contentious view.

[Oddley]

The main reason for the use of nitrite is to inhibit Clostridium botulinum bacteria. from what I have read they are not quite sure how it interacts with the bacteria but are sure it inhibits it. There are many sites on the web with info on this subject, Including the FDA. Colour and taste are definitely of secondary importance.

The micrococcaceae bacteria lives mainly on the skin of animals and humans, the inside of meat I believe is reasonably sterile. That's why chefs sear the outside of steak but can leave the inside rare. perhaps someone with some expertise in that suject can shed some light on it.

[georgebaker]

Hi
following on from what Oddey said I think thats why you must use tongs not a fork to turn the meat.

E Coli 0157 is many times more dangerous than the other types needing far fewer individual bacteria to cause illness.

George

[saucisson]

Yes I'm with you on this Oddley, several organic suppliers openly state they reluctantly add nitrites to keep their customers alive, not for flavour orcolour considerations.

Dave

[Lee]

Yes I'm with you on this Oddley, several organic suppliers openly state they reluctantly add nitrites to keep their customers alive, not for flavour or colour considerations.

Dave

I imagine there's many different versions of these curing recipes, and the cumulative effct of the temperature, the salt, and the nitrates all contribute to the preservation. Known as Hurdle preservation in the trade for obvious reasons, they all stack up, and if you take one out, then you have a problem (if you stack hurdles???)

[Wohoki]

The reason that chefs sear meat on the outside is entirely to do with flavour, and nothing to do with any bacterial load. The same cuts of meat can be used either as a fried steak or made into tartar and served raw with no health consequences to the consumer, and this includes, as an example, beef that has been hung for 6 weeks and more post slaughter. Obviously this doesn't apply to pork or chicken, but in these cases the bacterial load is endemic to the flesh, rather than surface contamination, but it does apply to beef, lamb/mutton and most real game and all fish.

You don't stick a fork in your steak to turn it because it bleeds into the pan, which cools it and ruins the finish.

(I did say that it would be a contentious POV I'm still not entirely convinced: I think that good meat handled well can be cured without adding anything more than salt and possibly sugar, the nitrate/nitrite cures may be of benefit if you are working on a huge scale, or with less than perfect meat. I do use #1 in sausage that I smoke, just to be on the safe side as I feed them to my kids, but I happily consume bacon that has been cured in nothing more than seasalt.)

[Oddley]

The only reason I stated the case of searing is that I have been told by a number of caterers that this was the primary reason for this especially for carpaccio style meats.

On the various .gov sites commutated meats are advised to be handled more carefully because of the bacteria spread from the surface throughout the meat. so I think we will have to agree to disagree about the sterility of muscle meat.

You are of course at liberty to cure your bacon how you please, if you choose to do so just with salt the chances are very small that you will have botulism poisoning, but the problem with that reasoning is, it only takes one time to kill you.

[saucisson]

(I did say that it would be a contentious POV I'm still not entirely convinced: I think that good meat handled well can be cured without adding anything more than salt and possibly sugar

I have no problem at all with this, it's a fine point of view.

As I have no idea how good or well handled the meat I get is, I will treat it with nitrate just to be sure. If people want to leave it out that is of course their personal decision (not having a go at you Wohoki by any means ).

As far as I can work out nitrate/nitrite reduces the risks of Botulism to virtually zero, so it is entirely up to the consumer/home curer to decide whether the risk was there in the first place.

Dave

Edit: Although I now know a huge amount more than I did a few days ago about bacteria in and on food, I still only know a tiny amount...

[pokerpete]

The only reason I stated the case of searing is that I have been told by a number of caterers that this was the primary reason for this especially for carpaccio style meats.

On the various .gov sites commutated meats are advised to be handled more carefully because of the bacteria spread from the surface throughout the meat. so I think we will have to agree to disagree about the sterility of muscle meat.

You are of course at liberty to cure your bacon how you please, if you choose to do so just with salt the chances are very small that you will have botulism poisoning, but the problem with that reasoning is, it only takes one time to kill you.

As far as I know Urschell developed their Comitrol system for chipping and reforming a patty type product.
The source of the meat did not specify that it was of the same carcase.
I don't find that commutated meat products fit in with any part of this thread.

[saucisson]

I think I'm to blame for bringing up the issue of whether bugs are in or on the meat.

I think we were still trying to pin down how those friendly micrococci manage to convert nitrate to nitrite to nitrous acid to nitrous oxide while we kill everything else

I can't see how they can do their job if they are on the outside at 15% salt ?

dave

[Wohoki]

I think that the reason carpaccio is seared on the outside by caterers is one of economy. True carpaccio is heavily trimmed of the outside "crust" before slicing, and this would represent a serious cost as the scraps are disguarded, whereas searing would allow you to serve the whole slice.


(And I didn't think you were having as go saucisson, I love the free and frank exchange of ideas we get here: God forbid that anyone should bite their tongues to avoid disagreeing with someone.)

I did find in Fergus Hendersons exellent "Nose to Tail Eating" that he ommits cures because he finds the effect on the meat to be too fierce, and I don't think anyone's died as a result of eating at St John's yet. But there's time

[Oddley]

To be honest after looking round I still can't find a definitive answer to the question of does the internal muscle meat of pork regularly contain bacteria.

To get a good nitrate to nitrite conversion the answer would have to be yes. But It just doesn't sit right. We could do with a food scientist.

Anyway here are some snippets I found on my quest.

"With pork chops or steaks, you've got bacteria contamination on the outside," says lead researcher Jennifer McClennan. And with ground meats, the bacteria are found throughout, making them more dangerous.

http://www.themodernreligion.com/health ... teria.html

Meat can have harmful bacteria on the surface from the slaughter process, equipment from the processing plant, or germs on hands, utensils, or kitchen surfaces. When meat is “ground up” at the supermarket and handled at home, this surface bacteria can end up inside the meat. This is what makes ground beef, for example, particularly at risk for E. coli O157:H7 contamination.

http://www.cfsan.fda.gov/~dms/fttmeat.html

Why does ham spoil inside near bone?

This is due to bacterial growth. The change of bone sour can be reduced by making sure there is plenty of curing salt mixture on the meat and the entire piece is immersed in the brine. Keeping the ham refrigerated during the entire cure and salt equilization period is a good preventive measure as the growth occurs before the salt penetrates these innner portions of the ham. Sometimes this occurs even in commercial operations with good temperature control.

VanGarde, Shirley J. and Margy Woodburn. 1994. Food Preservation and Safety. Principles and Practice. Iowa State Press, Ames Iowa.,, p. 87

http://food.oregonstate.edu/faq/meat/ham.html

[Wohoki]

A lot of your quotes make sence there: if the bacteria are on the outside of the meat, then whole pieces should be fairly free of them internally, but mincing will distribute them freely. Hence the need for cures in smoked sausage and salami, and a lesser need in whole cuts such as bacon and the like.