This Department of Agriculture logo and certain other organic symbols from accredited certifying organizations are usually meaningful because the government sets fixed standards for them. You'll find three tiers of organic labeling: "100% organic" (only organic ingredients), "organic" (at least 95 percent of ingredients are organic), or "made with organic ingredients" (at least 70 percent organic contents). Water and salt don't count toward the percentage of organic ingredients.

Any nonorganic ingredient must come from an approved national list. But "organic" might not mean much when it comes to fish, since proposed government regulations would allow the term to be used for fish raised in a highly polluted environment and fed meal made from wild fish, which could be contaminated with mercury, PCBs, and other pollutants. For more information on organic foods and a list of certified symbols, go to Consumer Reports Greener Choices Eco-Labels Center.