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Let's say that I want to keep meat in my fridge for a week. From what I read, this is frowned upon, as it leaves time for bacteria to develop and to produce toxins which won't be destroyed by cooking the meat. However, I also read that in cold, salty conditions, only favourable bacteria develop, and that's how sauerkraut and other pickles are made.

So, can I safely keep raw meat in the fridge for a week (or more) if submerged in salty water ? What would be the appropriate salt concentration and maximum keeping time ?

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I can only partially answer your question but still:

  • Cold : yes, absolutely
  • Salt : yes, that would help.
  • Water ??? No.

Bacterias love water. When trying to preserve meat you actually want to do the opposite, you want to keep it dry. That's how curing works actually. Absorbant paper is often used to prevent the meat from deteriorating by swimming in its blood.

You mentionned pickles, pickling works thanks to acidity. And pickling meat isn't a good idea, as the acid will deteriorate the meat fast.

Now I will NOT tell you here that keeping meat 1 week in the fridge is a good idea or guarantee that it's safe. But cold and salt will definitely slow down bacterial growth.

Lastly, keep in mind that what's most important is to know what meat you bought. I mean who you bought it from, how it's been processed and preserved...

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    My understanding was that bacteria like a humid environment, but that being completely submerged and mostly deprived of oxygen wouldn't allow them to grow as much. – user76391 Jul 7 at 15:01
  • I was actually going to propose vacuum packing if you have access to it, but it's unlikely in a home environment. – Clepsyd Jul 8 at 12:19
  • @user76391 many of the bacteria that cause food-poisoning can grow anaerobically (e.g. Salmonella species), yes they will typically grow slower anaerobically, but they are still present and can cause serious illness. – bob1 Jul 8 at 16:25
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What you are essentially describing is a brine. That is a saline water solution that trough the process of osmosis draws in moisture trough the cell walls and releases them. This has the effect of making the cell walls more absorbent of moisture which leads to juicier meat.

The problem is for brining you typically want to leave the meat in the brine at room temperature. Doing the brine at cold temperatures retards the osmosis effect. Now that does not mean it cannot be done, it is just going to take 2 to 3 times as long.

As for the concentration of salt that depends on what you are brining and what level of saltiness you want. For veggy pickles I have seen solution as low as 5% but for meat you can have a general rule of 6% - 8%. This means 60 - 80 grams of salt per liter of water.(Weigh the salt, different salts have different volumes.).

As for how long brines can last, if you take accounts of how the sea voyages that explored the new world seriously then brines can keep meat for up to two years.

If you live in the new world it is fun to think about how different our countries histories would have been if the European settlers could feed themselves in their long sea voyages with brined meat. It is actually the food stuff that made their voyages possible.

However, I also read that in cold, salty conditions, only favourable bacteria develop, and that's how sauerkraut and other pickles are made.

There are four main types of lactic acid bacteria are commonly present in sauerkraut: Leuconostoc mesenteroides, Lactobacillus brevis, Pediococcus pentosaceus and Lactobacillus plantarum.

Sauerkraut is made by a process of pickling called lactic acid fermentation that is analogous to how traditional (not heat-treated) pickled cucumbers and kimchi are made. The cabbage is finely shredded, layered with salt, and left to ferment.

SOURCE

  • I would say the safety risks out weigh any retardation of effect by cold temperature. Brine meat and fish at refrigeration temperatures! – moscafj Jul 8 at 12:04
  • @Neil Meyer - I think the voyages typically used salt-meats rather than brined (as used in cooking terms nowadays) - they were indeed in brines, but very heavily salted (around 40% salt) and went through several steps before getting to this stage - see here; a couple of paragraphs below the ship's biscuits picture. – bob1 Jul 8 at 16:36
  • Also @Neil Meyer, the critical bit about sauerkraut is that these bacteria are naturally present on the cabbage. These bacteria are unlikely to be present in any significant numbers on meat. The brining enhances growth of these over other species under conditions in which lactic acid fermentation happens - resulting in a pickling (from the acid produced) of the cabbage, as well as the brine. – bob1 Jul 8 at 16:46
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Corned beef actually requires keeping brisket in a water, salt and spice solution for at least a week.

So it’s not just a way to preserve meat, but also a way to enhance it.

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For me, it depends which raw meat. I wouldn't keep pork or poultry for very long unwrapped but beef definitely needs an airing to develop it's taste. At least four days, if it's from a supermarket, no more than ten in my fridge. I know it's ready when the outside is very dark. Then I'll dampen it and sprinkle with sea salt and roast it at the top of a very hot oven for 15-20 mins per lb. This works well for me as my joints are typically less than 2lbs. I imagine if I was cooking a much larger piece, I'd have to rethink my strategy. Other meats I would air in the fridge would be venison and for a shorter period lamb and goat. And definitely the muscular flesh of these animals and not the offal.

I wonder what toxins are produced by the bacteria you mentioned? I don't keep an over sterile environment and believe competition will keep dangerous pathogens from establishing a significant threat. After all, I'll eat plenty of other things, like salad, out of the fridge raw without worrying what microbes lurk on their surface. We need to keep our immune systems learning!

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There's a commonly used mnemonic device in the Food Safety industry, known as FAT TOM (here's Wikipedia's breakdown):

  • Food There are sufficient nutrients available that promote the growth of microorganisms. Protein-rich foods, such as meat, milk, eggs and fish are most susceptible.
  • Acidity Foodborne pathogens require a slightly acidic pH level of 4.6-7.5, while they thrive in conditions with a pH of 6.6-7.5. The United States Food and Drug Administration's (FDA) regulations for acid/acidified foods require that the food be brought to pH 4.5 or below.
  • Time Food should be removed from "the danger zone" (see below) within two-four hours, either by cooling or heating. While most guidelines state two hours, a few indicate four hours is still safe.
  • Temperature Food-borne pathogens grow best in temperatures between 41 to 135 °F (5 to 57 °C), a range referred to as the temperature danger zone (TDZ). They thrive in temperatures that are between 70 to 104 °F (21 to 40 °C).[3]
  • Oxygen Almost all foodborne pathogens are aerobic, that is requiring oxygen to grow. Some pathogens, such as Clostridium botulinum, the source of botulism, are anaerobic.
  • Moisture Water is essential for the growth of foodborne pathogens, water activity (aw) is a measure of the water available for use and is measured on a scale of 0 to 1.0. Foodborne pathogens grow best in foods that have aw between 0.95 and 1.0. FDA regulations for canned foods require aw of 0.85 or below.

Typically, time and temperature are favored in CCP's in the FSIS-preferred HACCP model (I won't say it's deprecated, but it is quite dated). While I've never worked with a meat product that requires a brine processing step, I would infer that salinity could be utilized as a control; the question would then be whether any of the species have pathogens of concern that could survive and proliferate under those conditions (if controlled / reduced, you can achieve lethality in a subsequent step as well). There would also need to be a control point for monitoring of the brine salinity, which will also require either a) a Calibration Pre-Req program for electrical-type equipment, or b) certs of accuracy from manufacturer of titration kits.

Now, to answer your question specifically: please refer to FSIS Compliance Guidelines here. Note that parameters would need to be specific to species (swine, bovine, poultry) and intended use (RTE or NRTE, Shelf Stable or other, etc).

Lastly, an additional observation on my end: there is one other processing step which could possibly incorporate brining, and that's water slacking (also known as submerged defrosting). We don't typically use this, but have a contingency program in place that allows for it as a means of rapid preparation in the event of raw material shortages.

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