Fish sauce are made with anchovies, mackerel, scabbard fish and salt. The bigger the fish, the more mercury you might expect, especially if predator fish like scabbard fish. They do not have any additives like sugar, hydrolyzed protein, or preservatives. Vietnamese prefer sauces without a strong smell, and transparent with a deep golden amber color. "First press" fish sauce, meaning the sauce is bottled from the first time the fermenting barrels are drained, also indicates quality. Lastly, when measuring the nitrogen level of fish sauces (N), most fish sauce on the market falls within the mid 20N range. Anything over 30N is
Fish sauce were genuine fish sauce from 18 production sites in 12 provinces. Twenty samples from production sites in eight provinces were adulterated fish sauce. Tests showed that none were contaminated with botulinum toxin types A, B, E and F and were free of clostridium botulinum bacteria. In 2018, rumours again surfaced concerning banned Thai fish sauce. The variety from Vietnam is called "nước mắm". Two areas in Vietnam are most famous for producing fish sauce: Phú Quốc and Phan Thiết. Popular brands in the US include Mega Chef, Red Boat, 3 Crabs, Golden Boy, and Hòn Phan Thiết. Vietnamese fish sauces