<<But plain ol' pork and salt would be fine.  Is there a way to find bacon
that's just that, pork and salt?>>

The nitrates help preserve the red color in bacon, otherwise it turns an
unappealing grey in a short period of time.  Nitrates serve other functions
too, such as inhibiting the growth of pathogenic bacteria, as described in a
"speel" below.  But salt may be able to do this by itself, as it lowers the
water activity level necessary for pathogen survival (<.85 aw)

BACON

Bacon is cured by the dry rubbing process (Lee, 1991).   This involves
rubbing the surface of pieces of meat with curing agent and storing the meat
in a drying agent for long periods of time. (Ontario Ministry of Health,
1985).

The purpose of curing is to:
1. develop flavour
2. develop a permanent desirable colour
3. inhibit the growth of pathogenic (disease-causing) bacteria and other
undesirable microorganisms which cause decomposition (i.e. to preserve)
(Ontario Ministry of Health, 1985).

The curing agents permitted are sodium chloride (salt), sugar, sodium
nitrite, and vinegar, but only the first three are commonly used (Frazier +
Westhoff, 1988).  Other additives may include ascorbates (speeds up nitric
oxide production) and phosphates (decreases shrinkage) (Lee, 1991).

Sodium chloride (salt) is primarily used as a preservative and flavoring
agent.  Its primary purpose is to lower the water activity (Frazier +
Westhoff, 1988) [Spoilage and disease-causing bacteria require water in
order to live and grow in numbers.  Salt reduces the amount of water
available to these microorganisms, thereby limiting their growth]

Sugar adds flavor and also serves as an energy source for the
nitrate-reducing bacteria.  Sucrose is used chiefly, but glucose can be
substituted if a short cure is employed (Frazier + Westhoff, 1988).

Sodium nitrate converts to sodium nitrite and nitric oxide in the presence
of nitrate-reducing bacteria.  Sodium nitrite has a bacteriostatic effect
(prevents the growth of bacteria), while nitric oxide primarily is
responsible for the red pigmentation of the meat (Frazier + Westhoff, 1988)
[otherwise meat would be grey and gross-looking.]  [aside: nitrites also
combine with secondary amines in our digestive tract to form nitrosamines,
which are carcinogenic (cancer-causing) and teratogenic (causes
defects in developing fetuses).  For this reason, it is recommended that
large amount of nitrites be avoided in the diet].

References

Frazier, W + Westhoff, D. (1988). Food Microbiology 4th Edition. Chapter 14:
Contamination, Preservation, and Spoilage of Meats and Meat Products.
p225-228

Ontario Ministry of Health (1985). Principles of Examination and Evaluation
of Meat Manufacturing Processes. p3-5

Lee, Marilyn. (1991) Food Hygiene 2.  Ryerson Polytechnic University:
Toronto, Ontario

Rob