Wednesday, July 2, 2008

Nitrate Cured Salami

I spent a few minutes this week talking to Francois Vecchio, the man behind the crespone, finocchiana, cacciatore and felino salamis we carry. He gave me a chemistry lesson on salami making that I thought was worth sharing.

People are often worried about meat cured with nitrates. Is it a valid concern? I’ll get to that in a minute. First let me explain how nitrate cures meat. Welcome to a brief voyage through high school chemistry with apologies to mad scientists if I get any of the specifics incorrect.

Sodium nitrate NO3 is added to salami ingredients before they’re stuffed into the mostly air proof casing. Inside, the bacteria and microbial organisms live in an anaerobic environment—no oxygen.

Their activity sucks one of the three oxygen molecules away, turning sodium nitrate into sodium nitrite NO2. Sodium nitrite is unstable and aggressive to microbes. It’s the compound that does the real work of curing, making it safe for us to eat.

While it does its job another oxygen molecule is leeched off. What’s left is nitric oxide NO. This fixes the pigment color, keeping salami red. This molecule is safe.

Even though we started the cure with NO3 we ended up with NO. While Francois adds 150 parts per million of sodium nitrate to start the cure, only 2 or 3 PPM are left. The traditional thirty day curing process eliminates the substance.

So if cured salami doesn’t have any sodium nitrate or nitrite left, why are people afraid of it?

While traditionally cured meat doesn’t have any sodium nitrate/nitrite, non-traditionally cured meat may. During the middle of the last century, in between inventing Twinkies and Cheese Whiz, food scientists deciphered the chemistry that I just explained. Until then it’d been a two thousand year process that no one understood – people just knew it worked. The scientists correctly identified sodium nitrite NO2 as the money molecule. It did the majority of the curing work. NO3 didn’t seem to do much, so they experimented with adding NO2 directly to the meat, cutting NO3 out of the game. It worked. It saved time. Meat could be cured almost overnight. It could go to stores faster. It was a huge success.

Sort of. The problem is when the cure is rushed, NO2 doesn’t disappear like it does when you cure traditionally over thirty days. It’s still present in the meat. NO2 is a carcinogen.

That’s the reason people are worried about nitrate cured salami. Meats may be cured with sodium nitrite – not nitrate – and rushed to market when the nitrite carcinogen is still present. This isn’t true for the salamis we carry.

What about the “no nitrate” meat at supermarkets?

Nitrates are necessary for curing meat. You can’t cure without them and keep meat pink and safe. But if nitrates are necessary for curing meat, how can places like Whole Foods carry meats they say are nitrate free?

The trick is celery. It’s high in nitrates. Concentrated celery juice is used in the curing, instead of the naturally occurring mineral sodium nitrate. The FDA allows it to be called “Natural Flavor” instead of “Sodium Nitrate.”


Andrew said...

Terrific post. You mention concentrated celery juice. I'm curious, is this just a matter of combining water with some form of dehydrated celery that's been ground to a powder?

I just dehydrated and then ground a bunch of celery, but it's not clear how I then make the leap to a solution that will cure meats I'll be dehydrating at home. Any clues?

Mo Frechette said...

I'm not an expert in this area and I'd hesitate to suggest you do something at home that strays far from proven food-safe methods. Saltpeter is probably still the safest way to cure.

If you're looking for good reference material, I recommend Ed Behr's Art of Eating #80 and Jane Grigson's book Charcuterie & French Pork Cookery.

Anonymous said...

Great post!
I have been curing meats for a while now with Cure#2 which includes Nitrate/Nitrites. I have always been a huge fan of understanding how the people of antiquity cured meats before the understanding of Nitrates. Would you know or have you ever tried to cure salami using just pure sea salt? Do you know if it will keep the pink color with just salt? How did they do it? Are there any records of how it was done?

Mo Frechette said...

Hams like Prosciutto are cured exclusively with salt and remain pink. However, they're cured much longer than salami — usually 9 months or more, vs less than 2 months — and the same rules may not apply.

Anonymous said...

Is there any sure way of knowing how long a meat from the deli has been cured? Do any of the large meat companies still cure for longer than 30 days?

Thanks for the post.

Unknown said...

Anyone dry curing meats of a large diameter (9 cm or more) still need at least 30 days dry time by CFIA rules. So yes, large companies are still curing for that long, and much longer depending on the product.

What I find amusing is that people believe nitrite from celery powder is "safer" than that which is produced in a lab. It is chemically the same material, used for thousands of years to assist with curing meats. Some companies are just banking on the labelling loophole of celery powder or the like to avoid having to list "sodium nitrite" as an ingredient.