Nitrates and nitrites are used to "cure" meat.  Their role was likely discovered by accident and can be traced to the use of salt that happened to be contaminated with potassium or sodium nitrate, commonly known as “saltpeter.”  Meat treated with these chemicals retains a red colour, acquires a characteristic taste and most importantly, is less amenable to contamination with disease-causing bacteria, particularly the very dangerous Botulinum clostridium.
By the 1980s it became apparent that certain bacteria were capable of converting nitrates into nitrites and that nitrites were the actual active species.  Consequently nitrites are now added directly to processed meat instead of relying on bacteria to produce them from nitrates.  This allows for better control of nitrite concentrations, a critical aspect of processed meat production.  Why critical?  Because it is well known that nitrites can react with amines, naturally occurring compounds present in meat, as well as in human tissues, to form nitrosamines.  And that is the fly in the hot dog.  Nitrosamines can trigger cancer!  Of course demonstrating that nitrosamines can produce mutations in a Petri dish or that animals treated with high doses develop cancer, does not mean that these compounds are responsible for cancers in humans.  In any case, changes in manufacturing methods and a reduction in the amount of added nitrite have essentially solved the problem of nitrosamine formation in cured meat.
In spite of the epidemiological evidence linking nitrites to cancer being weak, and the established fact that 95% of all the nitrite we ingest comes from bacterial conversion of nitrates naturally found in vegetables, many consumers have a lingering concern about eating nitrite-cured processed meats.  But one person’s concern is another’s business opportunity.  In this case, producers have responded with an array of “natural” and “organic” processed meats sporting the catchy phrases such as “no synthetic preservatives” or “no nitrites added.”  But given the crucial role nitrites play in processed meats, how do you replace them?  Well, you don’t.  You just replace the source of the nitrite.
Celery has a very high concentration of natural nitrate, and treating celery juice with a bacterial culture produces nitrite.  The concentrated juice can then be used to produce “no nitrite added” processed meat.  Curiously, regulations stipulate that the traditional curing process requires the addition of nitrite and thus “organic” processed meats that are treated with celery juice have to be labeled as “uncured.”
Such terminology is confusing because most consumers look to “organic” processed meats in order to avoid nitrites, but the fact is that these do contain nitrites, sometimes in lesser, sometimes in greater amounts than found in conventional products.  That’s because the amount of nitrite that forms from nitrate in celery juice is hard to monitor, while in conventionally cured processed meats, the addition of nitrite is strictly controlled by regulations designed to minimize nitrosamine formation and maximize protection against botulism.  This means any risk due to nitrosamine formation or bacterial contamination in the “organic” version is more challenging to evaluate.
So what does all of this mean?  Basically, that buying “organic” hot dogs or bacon with a view towards living longer by avoiding nitrites makes no sense.  Limiting such foods because of their high fat and salt content, whether organic or conventional, makes very good sense.  Cutting them out totally, as the Physicians’ Committee for Responsible Medicine would have us do?  No thanks.  Remember that it is unrealistic to evaluate every bite of food as being “healthy” or “unhealthy!”  It is the overall diet that matters.  It is possible to avoid cured meats completely and still have a terrible diet while one can have a healthy diet by occasionally indulging in these tasty morsels.  Emphasize a mostly plant-based diet?  By all means. But dogmatic tirades against hot dogs?  That’s ideology, not science.
