It's entirely possible that Tandy/Todd don't care about at all expiration dates on food; whereas Carol, Erica, Gail, and Melissa are starting to panic about it.

I think season 1 stated it's been 2 years since the plague? And season 2 is about 6 months after season 1? I wouldn't worry about canned food just yet.
But my girlfriend and I watch the show together, and she gets grossed out by the concept that they're eating expired food, whereas I think they can get a few more…