What Is Acetic Acid?

FDA regulations at 21 CFR 184.1005 say acetic acid is known as ethanoic acid, that it occurs naturally in plant and animal tissues, and that it is produced by fermentation of carbohydrates or by organic synthesis. The FDA vinegar compliance policy says natural vinegars as they come from the generators normally contain more than 4 grams of acetic acid per 100 mL, and that when vinegar is diluted with water, the label must state the actual percent acid strength, which should in no case be less than 4 percent.

In food, 21 CFR 184.1005 says acetic acid is used at levels not to exceed current good manufacturing practice, which results in maximum levels as served such as 0.25 percent for baked goods, 0.8 percent for cheeses, 0.5 percent for chewing gum and 9.0 percent for condiments and relishes.

Concentrated acetic acid is corrosive. The New Jersey Department of Health says contact can severely irritate and burn the skin and eyes, leading to eye damage, that inhaling acetic acid can irritate the nose, throat and lungs, and that higher exposures may cause a build-up of fluid in the lungs, a medical emergency. The NIOSH Pocket Guide lists symptoms including irritation of the eyes, skin, nose and throat, eye and skin burns, skin sensitization, dental erosion and chronic bronchitis. The New Jersey Department of Health lists the OSHA and NIOSH workplace limits as 10 ppm, averaged over 8-hour and 10-hour workshifts respectively.