ppb stands for “Parts Per Billion.” It is a unit of measurement commonly used for measuring trace amounts of contaminants, like heavy metals. 1 ppb means that for every one billion parts, one part is the substance of interest.
*10ppb for fruits, vegetables (excluding single-ingredient root vegetables), mixtures (including grain and meat-based mixtures), yogurts, custards/puddings, and single-ingredient meats; 20 ppb for root vegetables (single ingredient); and for dry infant cereals. Action Levels for Lead in Food Intended for Babies and Young Children: Final Guidance for Industry, January 2025, U.S. Department of Health and Human Services Food and Drug Administration Center for Food Safety and Applied Nutrition. 
** Baby food and processed cereal-based food for infants and young children up to 3 years old.  COMMISSION REGULATION (EU) 2023/915, of 25 April 2023, on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006, Annex 1, CELEX_32023R0915.   
***Inorganic Arsenic.