#nitrites

MEAT CURING 101

Or, everything you didn't want to know about meat curing :)

The first thing you have to know about meat curing is that it was a complete accident. Humans noticed that meat turned a bright pink color after it was smoked or certain ingredients were used in the smoking/drying/cooking process. The reason why it turned pink was because of natural nitrates found in smoke (that's what causes the pink smoke ring in BBQ meat), as well as sea salt and saltpeter. The awesome part about all of this, was that this accidental curing acted as an ancient antimicrobial that protected against C. botulinum (link to USDA FSIS food safety fact sheet), that nasty spore former that causes improperly canned foods to blow up like a balloon (also, if you find a can in your pantry that has blown up like a balloon, dO NOT CONSUME IT).

Why do humans continue to consume this cured meat. Well, it tastes pretty damn good. Go to any fast food restaurant and chances are there is a burger menu item with bacon. Or a breakfast item with ham. It just tastes GOOD. It also has that pretty pink color that stays with the meat after you cook it compared to the brown color you get when you cook uncured items. Moving away from the food quality aspects, it also helps extend shelf life of a meat product AND you have the food safety part I mentioned above. Not only does it protect against C. botulinum, but C. perfingens and L. monocytongenes as well.

How does this magical substance work??? Well, it's not magic, it's science! The protein responsible for meat color is called myoglobin.

In the middle of myoglobin, is an iron atom. What the redox state of the atom and what attaches to it affects the shape of the myoglobin, and this alters the color you see when you look at meat. So when it's just myoglobin hanging out by itself, a water molecule is attached to it and it appears purple. When oxygen attaches to the iron atom, it appears red. When the iron atom goes from a ferrous to a ferric state (basically, what happens when metal rusts), the meat appears brown. You can actually see this when you are out grocery shopping! If you see a piece of meat in a vacuum sealed bag, it appears purple. If the meat is in an over wrap tray, or in a display in a butcher counter, it looks red. When you see meat that has the discount sticker on it, it's starting to turn brown and needs to be consumed or frozen soon (That's why it was discounted. The meat is still safe to consume as long as you cook it properly and eaten that or the next day).

When you add nitrite to the mix, that's how you get the pink color change! The ancient curing methods used nitrate, but that needs to be reduced down to nitrite by a fermentation or a cure accelerator. Modern curing just uses nitrite, most commonly sodium nitrite. The sodium nitrite gets reduced to nitric oxide (this can be accelerated by adding ascorbate or erythorbate) and that binds with the meat to make nitrosomyoglobin. As the meat cooks, this creates nitrosohemochrome, which gives you the pink color!

In the US, most meat products are allowed 150ppm (parts per million, or 0.015%) according to the meat block weight. For bacon, it's a little lower at 120ppm (0.012%). Cure is very regulated in the US as well, because too much can harm humans. I remember when I was working as a quality assurance tech at a ready-to-eat (RTE) facility, I would have to weigh all the cure that production would use for the day. The weights and lot numbers of the cure would be recorded and tracked to make sure that the correct amount was used every day/night (depending on the shift). The storage was regulated as well. It could not be store above any other ingredient (so it wouldn't cause contamination if a bag opened), and it was locked up as well.

Like I mentioned earlier, modern curing used sodium nitrite (you might also see it called Sure Cure). It's normally white, but is dyed pink so it's not confused with other ingredients, like salt or sugar. Sure cure contains 6.25% nitrite, with the rest being salt. There are "natural" ingredients that can be used to cure meat, with the most common being celery powder. Cherry powder is also used as "natural" replacement for ascorbate, the accelerator mentioned above. Next time in the grocery store, check out the naturally cured bacon or ham. If the meat is pink, but the package says it is uncured, look on the back at the ingredient statement. Most likely, that product is using celery powder as its source of nitrite. The package might also say something about "no nitrites/nitrates added!". There will most likely be an asterisk next to that statement. Follow that asterisk to the bottom of the package to its partner asterisk. The statement there will probably says something along the lines to "except for nitrites/nitrates naturally found in celery powder and sea salt."