ORLANDO, Fla. -- A Local 6 News investigation showing case-ready ground beef enhanced with carbon monoxide remaining cherry red for months prompted tips from viewers that popular stores are selling the meat in Central Florida.

The report featured Kelly Hardesty, one of many Local 6 viewers convinced they were fooled by modified atmosphere packaging.

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"We opened the meat and it was an awful bad smell," Hardesty said, "It smelled like it had been about 10 days old maybe."

"Did you buy it because it looked good or did you actually check the sell-by-date?" Problem Solver Mike Holfeld asked.

"Because it looked good," Hardesty said.

Local 6 News reporter Mike Holfeld first reported in May that the process uses carbon dioxide, nitrogen and a small amount of carbon monoxide to deliver an enhanced cherry red glow that last weeks past the sell date.

The issue has prompted Orange County commissioner Linda Stewart to call on the state Agriculture Department to help "make the public aware of the practice," according to the report.

Stewart said she will bring the Local 6 News reports to the county commission and the state.

"What it's doing so far is exposing issues we may not have known existed even two weeks ago," Stewart said.

Local 6 News viewer response prompted Holfeld to examine products being sold at Wal-Mart and Target Super Centers, including a Lean Beef product.

Holfeld then took samples of the purchased meat to test labs at the University of Florida.

A technician injected an airtight syringe into the case-ready samples from Target, Wal-Mart and Laura's Beef.

He then injected the levels into a machine using a calibration curve --which is a standard to compare the levels.

All the samples had similar levels of carbon monoxide and carbon dioxide, the report said.

The carbon monoxide is consistent with modified atmosphere packaging, Holfeld said.

"I ran the calibration curve and on this (and) I can say for sure it is carbon monoxide and it comes at this time and this amount," Stefan Crynen said.

Crynen ran a second test on the Wal-Mart sample because the company said none of its case-ready beef is packaged in carbon monoxide.

"Our results seem to contradict that," Holfeld said.

"It's more than naturally occurs, so that's what I can say," Crynen said. "How it came in there, I have no idea if they do it on purpose or if it's in the facility some how because it is low but it is definitely in there."

The general manager for FPL foods, the company that supplies Wal-Mart in the area, told Local 6 that it uses a modified atmosphere but it does not include carbon monoxide, Holfeld said.

"We will run additional tests to figure out why we are getting those levels," Holfeld said.

"That sounds that sounds like the case-ready packaging doesn't mean carbon monoxide is used in every brand," Local 6 anchor Bob Frier said.

"That's right," Holfeld said. "The packaging is virtually identical. The atmosphere can include low or high levels of oxygen with carbon dioxide."

Holfeld showed a package of red beef purchased in March that remains red.

Stores like Publix, Kroeger and Albertson's refuse to sell the modified meat because it can be viewed as "deceptive," Holfeld said.

Also, Stuart will be asking Mayor Rich Crotty and the county commission to ask stores to get labels in place so consumers know what process is used.

Watch Local 6 News for more on this story.