It's a "naturally occuring" source of nitrates and/or nitrites, used in meat curing (think ham or hot dogs or beef jerky or bacon).
1. Good: Nitrites produce that pink color and particular salty flavor.
2. Good: Nitrites suppress bacteria growth.
3. Bad but outdated? In large enough quantities, nitrites will kill you. I seem to recall this being the main issue, but a quick google now mostly turns up the next point:
4. Bad: Nitrites also produce nitrosamines, which may be carcinogenic [citation needed].
5. Mitigation?: According to wikipedia, "The production of carcinogenic nitrosamines may be inhibited by the use of the antioxidants vitamin C and the alpha-tocopherol form of vitamin E during curing."
People are worried about some combination of [3] and [4], and so some meat producers use variations of "(dehydrated|fermented|cultured) celery (juice|extract|salt)" in the ingredients lists instead of directly listing nitrites as chemical names.
The counterreaction is to be suspicious of odd celery ingredients.
Since nitrites are essentially synonymous with cured meat though (must be used to prevent spoilage, no available substitute as far as I know, but also no significant other usages as far as I know), I'm not sure you actually need to go to the ingredients list here. Rather than memorizing synonyms for nitrites, I'd say a better rule of thumb is probably:
worried about nitrites ? stop eating cured meats : don't worry about it
EDIT: I just thought of another place they exist: celery salt. So, if you're worried about cured meats, also avoid the celery salt.
Meats can be cured with normal or sea salt rather than nitrite salts. Have to be careful though, because botulism can kill you a lot faster than nitrites will!
Sodium nitrite is used as a preservative in deli meats and generally thought to be bad for our health. It doesn't matter if it is mineral or plant derived.
1. Good: Nitrites produce that pink color and particular salty flavor.
2. Good: Nitrites suppress bacteria growth.
3. Bad but outdated? In large enough quantities, nitrites will kill you. I seem to recall this being the main issue, but a quick google now mostly turns up the next point:
4. Bad: Nitrites also produce nitrosamines, which may be carcinogenic [citation needed].
5. Mitigation?: According to wikipedia, "The production of carcinogenic nitrosamines may be inhibited by the use of the antioxidants vitamin C and the alpha-tocopherol form of vitamin E during curing."
People are worried about some combination of [3] and [4], and so some meat producers use variations of "(dehydrated|fermented|cultured) celery (juice|extract|salt)" in the ingredients lists instead of directly listing nitrites as chemical names.
The counterreaction is to be suspicious of odd celery ingredients.
Since nitrites are essentially synonymous with cured meat though (must be used to prevent spoilage, no available substitute as far as I know, but also no significant other usages as far as I know), I'm not sure you actually need to go to the ingredients list here. Rather than memorizing synonyms for nitrites, I'd say a better rule of thumb is probably:
worried about nitrites ? stop eating cured meats : don't worry about it
EDIT: I just thought of another place they exist: celery salt. So, if you're worried about cured meats, also avoid the celery salt.