URBANA, Ill. — Organic foods have gone from being specialty items in health food stores to lining the shelves of mainstream supermarkets.

Sales of organic products have climbed from $3.6 billion to $24.4 billion in the past 10 years alone, but many consumers don’t know what makes a food organic and whether the label is worth paying for, according to a University of Illinois Extension nutrition and wellness educator.

“When products seem to be identical in nutrients and quality, consumers don’t know which one to purchase,” said Mekenzie Lewis, who provided information that will educate consumers so they can make their own decisions based on their level of concern about pesticides, their budget and other considerations.

According to Lewis, the term “organic” is mandated by the U.S. Department of Agriculture and refers to the way farmers grow and process agricultural products, including crops and livestock.

“Some of the principles behind organic farming practices encourage soil and water conservation and reduce pollution,” she said.

The USDA requires organic products to meet specific standards that regulate how such foods are grown, handled and processed. Organic farming techniques emphasize biodiversity, integration, sustainability, natural plant nutrition, natural pest management and integrity.

Products produced under these principles and approved by the USDA will display a USDA Organic label, Lewis said.

“Companies abuse the term organic, so looking for the USDA seal is a safe way to know you’re getting a truly organic product,” she said.

Products that contain some organic ingredients may say “made with organic ingredients” on the label, but they may not use the USDA seal, Lewis noted.

Although many consumers are concerned that conventionally grown produce contains harmful chemicals that damage their bodies, research suggests that levels on organic produce can be only 30 percent lower, she said.

“Organic foods are not necessarily 100-percent free of pesticides, although pesticide levels generally fall within the allowable safety limits,” the educator said.

There are several other reasons to buy organic, including taste preferences, animal welfare and concerns about the effects of conventional farming practices on the environment, Lewis said.

“Finally, don’t get confused by similar terms that manufacturers use to make their product appealing,” she said. “‘All-natural,’ ‘free-range’ and ‘hormone-free’ are some of the other labels thrown around today.”

These descriptions must be truthful, but consumers shouldn’t confuse them with the term organic, Lewis said.