History of preservative production

For thousands of years, people preserved food using bacteria that produce lactic acid.The acid turns perishable vegetables and milk into longer lasting foods,like sauerkraut in Europe,kimchi in Korea,and yogurt in the Middle East.These cultured foods also populate your digestive track with beneficial microbes.Many synthetic preservatives are also acids.Benzoic acid in salad dressing,sorbic acid in cheese,and propionic acid in baked goods.