Difference Between Food-Grade & Lab-Grade Citric Acid

Citrus fruits have citric acid in them.

The main difference between food-grade and lab-grade citric acid is their level of purity. Food grade has to do with how safe a substance is to eat. Lab grade measures the purity of a substance for use in chemistry experiments.

Food Grade

Citric acid doesn't have to be pure in food we eat. The Food and Drug Administration considers citric acid safe for general consumption, but it's usually an ingredient or component of more complex food items, rather than something we eat by itself. Citric acid by itself at lab-grade levels of purity is a minor health hazard as an irritant.

Lab Grade

Science requires chemicals that have a high level of purity for use in experiments, because contaminants can muddle the results. Lab-grade citric acid actually comes in different levels of purity for different purposes--called technical grade, laboratory grade and reagent grade.

Citric Acid Uses

Many foods, such as lemons, limes and other citrus fruits, naturally contain citric acid. The processed-food industry uses citric acid as an ingredient in sodas and dessert items. Many household cleaning products include citric acid as well.

References

• Coastal Scents: Citric Acid MSDS
• Science Buddies: Guide to Purchasing Chemicals
• U.S. Food and Drug Administration: Database of Select Committee on GRAS Substances (SCOGS) Reviews--Citric Acid
• U.S. Dept. of Health and Human Services: Household Products Database--Citric Acid

Resources

• National Center for Biotechnology Information: Citric Acid--PubChem Public Chemical Database
• National Institute of Standards and Technology: 1,2,3-Propanetricarboxylic acid, 2-hydroxy-