The curing agents that may be used are regulated by the USDA. They include
a. Salt. Salt is both a curing agent and a condiment. It imparts flavor and
accentuates the natural taste of the meat. There are several types of salt available, but
dry, common salt produced by refining mined rock salt is the most desirable. Solar salt
obtained from seawater is undesirable because it may contain halophilic (salt-loving)
bacteria and produce a fishy odor in cured meats. Common iodized salt has an
undesirable effect on the action of nitrates and nitrites and may inhibit color fixation.
b. Nitrate and Nitrite. Nitrate and nitrite are used primarily to fix the color of
cured meat. When salt alone is applied to meat, the natural red color of the flesh is
destroyed, leaving it dull and unattractive. The USDA has established definite limits on
the amount and types of agents that may be used and on the amount of residue that
may be left in cured meats. During recent years, sodium nitrite (prepared either by
reduction of sodium nitrate or as a by-product of the synthesis of nitric acid from
atmospheric nitrogen) has been used. In the curing process, nitrates are reduced to
nitrites by bacterial action. The nitrites furnish nitric oxide, which unites with myoglobin
to form nitric oxide myoglobin (the pinkish-red color of cured meat). This nitric oxide
myoglobin is unstable until heated in excess of 120 F, where it forms the stable
compound, nitric oxide myochromogen.
c. Sweetening Agents. Granulated cane or beet sugar, dextrose or glucose
(corn sugar), and honey are all used in sugar-cure formulas. Sweetening agents do not
contribute any appreciable preservation action to the curing process. They function
primarily as a flavoring agent in toning down the brackishness of the salt.
d. Antioxidants. When fats are exposed to air, they tend to oxidize and
produce a rancid condition. Certain compounds will combat this oxidation and are used
in curing formulas. The USDA regulates the use of these compounds.
The use of spices in preserved meats antedates written history. Originally, it was
thought that spices possessed preservative powers. Many specifications for cured and
smoked meats establish definite requirements for the spices. Quality assurance
provisions for these components include physical examination as well as laboratory
testing and, in many instances, sensory examination for condition, foreign material,
flavor, odor, and color. Identity of spices is determined by examination of labels,
invoices, or similar documents.