Hydrochloric acid enzyme pepsin by self-cleavage. After leaving the stomach, the hydrochloric acid of the chyme is neutralized in the duodenum by sodium bicarbonate. The stomach itself is protected from the strong acid by the secretion of a thick mucus layer, and by secretin induced buffering with sodium bicarbonate. Heartburn or peptic ulcers can develop when these mechanisms fail. Drugs of the antihistaminic and proton pump inhibitor classes can inhibit the production of acid in the stomach, and antacids are used to neutralize excessive existing acid. Concentrated hydrochloric acid (fuming hydrochloric acid) forms acidic mists. Both the mist and the solution have
Peracetic acid registered peracetic acid as an antimicrobial in 1985 for indoor use on hard surfaces. Use sites include agricultural premises, food establishments, medical facilities, and home bathrooms. Peracetic acid is also registered for use in dairy and cheese processing plants, on food processing equipment, and in pasteurizers in breweries, wineries, and beverage plants. It is also applied for the disinfection of medical supplies, to prevent biofilm formation in pulp industries, and as a water purifier and disinfectant. Peracetic acid can be used as a cooling tower water disinfectant, where it prevents biofilm formation and effectively controls "Legionella" bacteria. A trade name