Cancer-fighting pink pineapples, heart-healthy purple tomatoes and lighter vegetable oils - all genetically engineered - may someday be on US grocery shelves alongside more traditional products.

These foods could receive government approval in the coming years, following the OK given recently to apples that don't brown and potatoes that don't bruise.

The companies and scientists that have created the foods are hoping customers will be attracted to the health benefits and convenience and overlook any concerns about genetic engineering.

"I think once people see more of the benefits, they will become more accepting of the technology," said Michael Firko, who oversees the US Department of Agriculture's regulation of genetically modified organisms, or GMOs.

Critics aren't so sure. They say there should be more thorough regulation of modified foods, which are grown from seeds engineered in labs, and have called for mandatory labeling of those foods. The Agriculture Department only has the authority to oversee plant health of GMOs, and seeking safety approval from the Food and Drug Administration is generally voluntary.

"Many of these things can be done through traditional breeding," said Doug Gurian-Sherman of the advocacy group Center for Food Safety. "There needs to be skepticism."

What could be coming next? Del Monte has engineered a pink pineapple that includes lycopene, an antioxidant compound that gives tomatoes their red color and may have a role in preventing cancer. The USDA has approved importation of the pineapple, which would be grown only outside of the United States. It is pending FDA approval.