Preservatives have a continuous inhibitory effect on the growth of microorganisms whose spoilage substances are metabolic substrates during use, and can inhibit the most prone to spoilage under different conditions during operation, especially when the general sterilization effect is insufficient. Still have a sustained effect. Mineral oil, coal tar, tannin for anticorrosion of fiber and wood, formaldehyde, mercuric mercury, toluene, butyl paraben, nitroguanidine derivative or scented resin for biological specimens. The use of preservatives in foods is limited, so there are some physical methods such as drying and pickling.
Special preservatives include organic acids such as acetic acid, vegetable oils containing oleic acid esters, and special essential oils such as mustard. For parts of the organism (such as the human body surface or the digestive tract), various preservatives (such as iodoform, phenyl salicylate, aniline dye or acridine pigment) can be used depending on the specific conditions.
With the increase of modern people's awareness of health and healthy eating, preservatives have become drugs in food. When people buy food in supermarkets, they have already reached the level of “consistency of preservatives”. In fact, preservatives are essential additives in many foods and are essential ingredients for preserving food. Normal doses of preservatives do not cause any harm to the human body at all.