Final answer:
Sodium nitrite in pickles acts as a preservative by inhibiting harmful bacteria growth and maintaining the red color of pickled meats, but its use is regulated due to its potential to form carcinogenic nitrosamines.
Step-by-step explanation:
The benefits of sodium nitrite in pickles include its ability to prevent food spoilage by limiting the growth of harmful bacteria that can cause food poisoning. Additionally, sodium nitrite helps to prolong the retention of the meat's red color, which is often desired in pickled meat products. However, the use of sodium nitrite is controversial due to its potential to react with organic compounds and form nitrosamines, which are carcinogenic compounds.
When sodium nitrite is added to processed meats, it is reduced to nitric oxide, which reacts with the heme groups in myoglobin, giving meat its characteristic red color. Also, this nitric oxide can hamper the function of iron-sulfur enzymes in bacteria, inhibiting their ability to produce energy (ATP), thereby acting as a preservative. Despite these benefits, the potential formation of nitrosamines during cooking of nitrite-preserved meats necessitates careful regulation and limitation by agencies like the FDA to safeguard consumer health.