Laboratory Methods. FDA sets scientific standards for testing foods for various contaminants, and in the case of fish, to confirm identity of the species. Labs and food companies worldwide use these standards to make sure that food products are safe to eat and drink.aboratory Methods. FDA sets scientific standards for testing foods for various contaminants, and in the case of fish, to confirm identity of the species. Labs and food companies worldwide use these standards to make sure that food products are safe to eat and drink.