The next time you take that hamburger off the grill, don't assume it is fully cooked just because the inside is brown.

The appearance of hamburger or any other meat can't be used to determine doneness, said Julie Albrecht, food safety specialist in the University of Nebraska-Lincoln's Institute of Agriculture and Natural Resources. Rather, a food thermometer is the only sure way to determine when meat is cooked properly.

"Many people use color as an indication of doneness, but new research shows color can't be trusted," Albrecht said.

The color of hamburger was one of four food myths listed in a report issued by the non-profit Partnership for Food Safety Education in recognition of September being National Food Safety Education Month.

When using a food thermometer on a hamburger, it should be inserted into the side of the burger. It is done when cooked to 160 degrees.

A thermometer should be used when cooking all meats, Albrecht said. Poultry is done at 165 degrees and fish at 145 degrees. The temperature of steak and beef roast is best determined by consulting PFSE's Web site.

Other myths identified by PFSE include a belief that lemon juice and salt will clean a cutting board. While lemon juice may inhibit the growth of bacteria, it does not kill it, Albrecht said.

The best way to sanitize a cutting board and other kitchen surfaces is by cleaning it with a mixture of 1 tablespoon of bleach in 1 gallon of water. Cutting boards can be sanitized in a dishwasher as well.

Another myth is that rinsing raw chicken with water will kill bacteria. The only way to kill bacteria in poultry is to cook it to its proper temperature, Albrecht said. Rinsing it under water will promote cross-contamination.

"If you do it in a sink it splashes all over the place and you get microorganisms in your sink area," she said.

The fourth myth is that hot food should not be put in the refrigerator. Many people leave hot food on the counter to cool it before refrigerating it so as not to heat up the refrigerator, Albrecht said.

Perishable food needs to be refrigerated within two hours after being cooked or bacteria will form, she said. Food left outside in heat of 90 degrees or higher should be discarded after one hour.

Large amounts of cooked food, such as a pot of soup, should be placed in smaller containers to cool it faster. Albrecht recommends containers no more than 3 inches deep.