Nitrite in cured meats

Thus, antioxidant effects of nitrite in cured meats appear to be due to the formation of NO. Kanner et al. (1991) also demonstrated antioxidant effects of NO in systems where reactive hydroxyl radicals ( OH) are produced by the iron-catalyzed decomposition of hydrogen peroxide (Fenton reaction). Hydroxyl radical formation was measured as the rate of benzoate hydtoxylation to salicylic acid. Benzoate hydtoxylation catalyzed by cysteine-Fe +, ascorbate - EDTA-Fe, or Fe was significantly decreased by flushing of the reaction mixture with NO. They proposed that NO liganded to ferrous complexes reacted with H2O2 to form nitrous acid, hydroxyl ion, and ferric iron complexes, preventing generation of hydroxyl radicals. 

Lee et al. (1978) investigated the possibility that sulfhydryl groups were required in the formation of the clostridial inhibitor in cured meats. Sulfhydryl groups of meat proteins were blocked by treatment with silver lactate, then the samples were cooked with sodium nitrite before inoculation with C. botuli num spores. Botulinal growth as measured by gas and toxin production was similar to controls without silver lactate treatment. They thus concluded that sulfhydryl groups were not required for the antibotulinal effects of nitrite in cured meats. 

Kanner, J., Harel, S., Shagalovich, J., and Berman, S. (1984). Antioxidative effect of nitrite in cured meat pnxlucts Nitric oxide-iron complexes of low molecular weight. ]. Agric. Food Chem. 32, 512-515. 

MacDonald, B., Gray, J. 1., and Gibbons, L. N. (1980b). Role of nitrite in cured meat flavor Antioxidant role of nitrite. J. Food Sci. 45, 893-897. 

Since one attribute of the use of nitrite in cured meats is its inhibition of the C. botulinum microorganism, concern developed whether added ascorbate would alter this action. From the various studies conducted (484,507-511) it appears that added ascorbic acid (up to 1000 mg/kg) does not influence the antimicrobial action of nitrite against C. botulinum... 

Cassens, R.G., Use of sodium nitrite in cured meats today, Food Technol., 49, 72, 1995. 

P.E. Jackson, P.R. Haddad and S. Dilli, Determination of nitrate and nitrite in cured meats using high-performance liquid chromatography,/. Chromatogr., 295, 471, 1984. 

The use of sodium nitrite as a preservative is a classic example of the often delicate balance between risk and benefit. On the one hand, there is an enormous benefit in reducing the prevalence of fatal toxins in meats by the addition of sodium nitrite. On the other, there is the potential risk that sodium nitrite may increase the level of nitrosamines in certain foods. Nitrites are still used as food additives, but the allowable level of nitrites in cured meats has been reduced. Debate continues on whether nitrite preservatives used at their current low levels actually pose a risk to the consumer. 

The use of nitrates and nitrites in cured meat products must comply with the provisions set out in Directive 2006/52/EC, which amends Directive 95/2/EC on additives other than colours and sweeteners. Currently authorised as food additives are sodium and potassium nitrites and sodium and potassium nitrates that may be sold only in a mixture with salt or a salt substitute. The indicative ingoing amount of potassium and sodium nitrites that are authorised for use are 150mg/kg and the residual amount is 50mg/kg (KNOj) in non-heat-treated, dried meat products, 100 mg/kg (NaNOj) in other cured meat products, canned meat products and 175 mg/kg (NaNOj) in cured bacon. The indicative ingoing amount of potassium and sodium nitrates is 300 mg/kg in all cured products and the residual amount in cured and canned meat products is 250 mg/kg, in pickled herring and sprat 200 mg/kg and in hard, semi-hard and semi-soft cheeses and dairy-based cheese analogues 50 mg/kg. 

Cassens, R. G. 1997. Residual nitrite in cured meat. Food Technol. 51 53-55. 

Nitrates are found in fairly high concentrations in beets, spinach, kale, coUards, eggplant, celery, and lettuce. AdditionaHy, nitrates and nitrites are commonly used in the curing solutions of bacon, ham, and other cured meats. In cured meats, nitrates and nitrites control the growth of microorganisms, particularly Clostridium botulinum, and also serve as color preservatives. 

These days, sodium nitrite replaces most of the sodium nitrate used in cured meats, except for that used in slow-cured country ham. 

N-Nitrosamines in Cured Meats Other Than Bacon. The presence of N-nitrosamines in cured meats other than bacon has been the subject of several recent surveys (19,58,59). In general, the majority of the positive samples contained extremely low levels of N-nitrosamine, usually less than I yg/kg (19,58). This low level could, in part, be attributed to the discontinuation of the use of nitrite-spice premixes in the mid-l970 s (l 9). In the Holland study (59), the predominant N-nitrosamines detected were NDMA and N-nitrosomorpholine (NMOR) and, generally, values of 4 yg/kg were obtained for each N-nitrosamine. More correctly, these are presumptive N-nitrsoamine levels since mass spectral confirmation of their identities was not achieved. 

In foodstuff preserved by addition of nitrate/nitrite (namely cured meat produce and cheeses) both methods of preservation introduce nitrosating species into the food matrix. 

A U.S. patent was issued in 1917 for the use of nitrite as a replacement for nitrate in curing brines (Doran, 1917, as cited in Binkerd and Kolari, 1975). Kerr et al., (1926) found that hams cured in a brine containing about 2000 ppm sodium nitrite were equivalent in flavor and color to hams cured with nitrate. The maximum nitrite level found in any part of the hams was 200 ppm. Based on these experiments, the U.S. Department of Agriculture (USDA) in 1925 authorized use of sodium or potassium nitrite in curing brines in federally inspected establishments, at 0.25 to 1 ounce per 100 pounds of meat, such that the finished product would contain no more than 200 ppm sodium... 

Benedict, R. C. (1980). Biochemical basis for nitrite inhibition of Clostridium botulinum in cured meat. J. Food Protection 43, 877-891. 

Pierson, M. D., and Smoot, L. A. (1982). Nitrate, nitrite alternatives, and the control of Clostridium botulinum in cured meats. Grit. Rev. Food Sci. Nutr. 17, 141-187. 

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