Today on
Meatingplace.com, one of the highlighted stories discussed the differences
between naturally and conventionally cured meat products. The original article can be seen here: http://www.meatingplace.com/Industry/TechnicalArticles/Details/42243. Since my graduate research is focusing on the
process of natural curing, I was definitely excited to see this sector of the
meat industry in the spotlight. Many
consumers might wonder about the differences among conventional, natural, and
organic meat products. “Organic” is a
well-defined, highly legalized term that can only be applied to foods that meet
strict requirements. “Natural” is more open
for interpretation. However, one of the qualifications
for natural (and organic) meat products is the exclusion of synthetic nitrites
and nitrates (Sebranek, Jackson-Davis, Myers, & Lavieri, 2012). Nitrite (mostly in the form of sodium
nitrite) is added to conventionally cured products such as bacon, ham,
frankfurters, bologna, salami, and others.
Nitrite plays many roles in meat products: a color fixative,
antioxidant, flavor imparter, and antimicrobial. So how can “natural” products match up to
their conventional counterparts without the addition of nitrite? Let’s investigate.
For thousands of
years, salt was added to meat in the act of preservation, and the ancient
packers eventually realized some salts preserved meat better than other salts. The more effective salt, known as saltpeter,
contained nitrate (Honikel, 2008).
Later, nitrite, which can be made from the nitrate added to meat, was
discovered to be the major component in curing.
Next, scientists realized nitric oxide, made from nitrite, was the
compound that bound to myoglobin (an oxygen-transporting molecule in muscle)
during meat curing (Parthasarathy & Bryan, 2012). Nitric oxide was also assumed to provide
antimicrobial protection, especially against anaerobic bacteria like Clostridium botulinum, which can produce
a deadly toxin that causes botulism (Cammack, Joannou, Cui, Martinez, Maraj
& Hughes, 1999). The interaction of
nitric oxide and nitrite with metal-containing compounds can also deter lipid
oxidation and, as a result, influence the flavor of cured meat products.
(MacDonald, Gray, Kakuda & Lee, 1980).
But if nitrite can
do all these important, wonderful things, why would it need to be
kept out of products? In the 1960s and 1970s,
concerns over the formation of nitrosamines in nitrite-containing meat products
were raised (Sebranek & Bacus, 2007a).
Nitrosamines are carcinogenic, and can be formed between nitrite and
secondary amines in a high temperature, low pH environment (Honikel, 2008). The residual nitrite amount (that is, how
much free nitrite is in the product after production) will determine the
chances of nitrosamine formation: more residual nitrite increases the potential
for these compounds to be made (Sebranek & Bacus, 2007a). However, inclusion of cure accelerators, such
as ascorbate and erythorbate salts, increases the rate of change of nitrite to
nitric oxide, reduces the amount of leftover nitrite, and thus decreases the
chances of nitrosamine formation (Parthasarathy & Bryan, 2012). Applying this knowledge to meat product
formulations has severely reduced the risk of dangerous nitrosamine levels in
meat products, and today the amount of residual nitrite in meat products is
about 1/5 of what it was forty years ago (Cassens, 1997).
Still, some
consumers prefer “natural” products for a variety of reasons, and meat
scientists are continuing to develop methods to make such products. The standard method involves the inclusion of
nitrate or nitrite from a natural source such as vegetables (Sebranek &
Bacus, 2007a). Celery, spinach, beets,
kale, and other vegetables are naturally rich in nitrate. When powders made from these vegetables are
treated with starter cultures (either before or after being mixed with other
ingredients), the nitrate is reduced to nitrite that can work its magic inside
meat products (Sebranek & Bacus, 2007a).
Certain problems arise from this, however: the exact amount of ingoing
nitrite may only be guessed, and it is generally lower than the amount of ingoing
nitrite in conventional products (Sebranek & Bacus, 2007a). The lower level of original nitrite can,
later on, jeopardize meat quality, depending on storage conditions (Sebranek
and Bacus, 2007b). Perhaps the most
critical concern for natural meat products is food safety; while lower ingoing
nitrite levels can mimic conventional flavor and color, sufficient antimicrobial
activity may not be observed in natural products (Sebranek, 1979).
While companies
would never intentionally sell sub-par products, consumers should be aware that
products made by different methods may have different qualities. Natural meat products do not contain
artificial ingredients, including pure sodium nitrite, and therefore the
products’ flavor, color, or longevity may not match those of conventional meat
products. Also, if consumers are
purchasing “natural” meat products merely due to concerns about nitrite intake,
they should be aware that the miniscule amount of nitrite in meat products (7
grams of nitrite per 100 pounds meat, typically) contributes just a small
fraction of nitrite to the human diet (Milkowski, Garg, Coughlin, & Bryan,
2010). The safeguards that sodium
nitrite provides against dangerous bacteria like C. botulinum, in my opinion, outweigh the minute risks of nitrosamine
formation.
References
1.
Sebranek, J.G., Jackson-Davis, A.L., Myers, K.L.,
Lavieri, N.A. (2012). Beyond celery and starter culture: Advances
in natural/organic curing processes in the United States. Meat
Science, 92, 267-273.
2.
Honikel, K.O.
(2008). The use and control of
nitrate and nitrite for the processing of meat products. Meat
Science, 78, 68-76.
3.
Parthasarathy, D.K., Bryan, N.S. (2012).
Sodium nitrite: The “cure” for nitric oxide insufficiency. Meat
Science, 92, 274-279.
4.
Cammack, R., Joannou, C.L., Cui, X.Y., Martinez,
C.L., Maraj, S.R., Hughes, M.N.
(1999) Nitrite and nitrosyl
compounds in food preservation. Biochimica et Biophysica Acta, 1411,
475-488.
5.
MacDonald, B., Gray, J.I., Kakuda, Y., Lee, M.L. (1980).
Role of nitrite in cured meat flavor: chemical analysis. Journal
of Food Science, 45(4), 889-892.
6.
Sebranek, J.G., Bacus, J.N. (2007a).
Cured meat products without direct addition of nitrate or nitrite: what
are the issues? Meat Science, 77, 136-147.
7.
Sebranek, J., Bacus, J. (2007b).
Natural and organic meat products: regulatory, manufacturing, marketing,
quality and safety issues. American Meat Science Association White
Paper Series, 1, 1-15.
8.
Milkowski, A., Garg, H.K., Coughlin, J.G., Bryan,
N.S. (2010). Nutritional epidemiology in the context of
nitric oxide biology: A risk-benefit
evaluation for dietary nitrite and nitrate.
Nitric Oxide, 22, 110-119.
