Yes, I recall that incident. If you believe it will support your point, then by all means state your claim regarding that incident and present the details of it.ABC news did an undercover report from a grocery store chain, Food Lion where they reported employees mishandled food. Turns out only the undercover reporters mishandled food and tried to pass it off as the chain's employees.
My memory is somewhat different from the summary you present. There was indeed lying involved -- but not in the story ABC broadcast, and not in ABC's defense of the story.
As I recall, and as a quick Google seems to confirm, ABC investigative reporters went undercover to check out stories about Food Lion deliberately selling food which should have been discarded. They found this was indeed happening, and videotaped evidence of this.
Food Lion has never legally disputed the facts of the 20/20 expose. They never sued either ABC, or the reporters involved for libel (or slander). My guess is because that's because the evidence ABC had gathered and broadcast is pretty clear-cut, and truth is an effective defense against libel in the US.
What Food Lion did sue ABC over is the method ABC used to get the story. In order to get jobs at Food Lion, the ABC reporters lied on their job applications. They failed to mention that they were ABC reporters who were applying for the job in order to get the good on Food Lion. Therefore, according to Food Lion, they were guilty of fraud (getting jobs under false pretenses). They were guilty of trespassing (since they had gotten the jobs under false pretenses and weren't genuine employees). And they were guilty of breach of loyalty, since they were gathering evidence against Food Lion while ostensibly working as employees of Food Lion.
As I say, that's from memory (and a quick Google) so I may have some details wrong. So if you feel this incident supports the point you are making, by all means state your claim clearly and present the evidence to support it. For this to be parallel to the AP incident, you need to show that the original 20/20 story was wrong and that someone at ABC then lied about that. Please present this statement, and a link to where it appears so that I can check it out for myself.