By Karen Denice
CNN Medical Senior Producer

What does the “Sell-by” date really mean?

Is the sell by date really a “consume-by” date? Everyone seems to have an opinion, but what are the facts? I was raised to never waste food. My grandfather used to cut the mold off my bread and hand it back to me. So, I have a rather liberal view of food safety – more of a sniffer than a by-the-book, go-by-the-date kind of gal.

But recently I was having friends over for dinner and wondered if I could be putting them at risk. The meat I was using had only a sell-by date and had been frozen every minute since then. Granted that sell-by date was in September and I was cooking for them in March. Don’t flinch!

For the dinner I used my personal sniff, color and texture test and decided it looked good, but that just made me wonder what do those dates on packages really mean? So I did some research.

Surprisingly food dating is not generally required by the federal government although 20 states do require it. There are multiple “dates” that may end up on your food; the one in question for me was the purchase or sell-by date. These dates are not an expiration date, but they do reflect when the food is at its highest quality. Depending on the food, it will stay good anywhere from one to two days [poultry] to five weeks [eggs] after the sell-by date if handled properly. (Check out this chart)  

There are also “Best if used by” or “Use-by” date stamps. These sound like your food might go bad, but again the U.S. Department of Agriculture says this refers only to the quality of the food – not safety.

If you freeze food the dates and advice gets murkier. Experts say freezing prevents the germs that cause food to spoil, but that doesn’t mean you’ll like the taste when it’s defrosted. Anything from freezer burn to how long it was frozen and the quality of the food will impact how good, or not good, it will taste.

Lucky for me, my friends enjoyed the meal and as it turns out it was unlikely they would have gotten sick anyway.

So are you a sniffer or a by-the-date person? Have you ever gotten sick taking a risk?

Editor's Note: Medical news is a popular but sensitive subject rooted in science. We receive many comments on this blog each day; not all are posted. Our hope is that much will be learned from the sharing of useful information and personal experiences based on the medical and health topics of the blog. We encourage you to focus your comments on those medical and health topics and we appreciate your input. Thank you for your participation.

By Caleb Hellerman
CNN Senior Medical Producer

There’s a controversial new weapon to help fight off food poisoning. Today, the FDA is putting into action a plan that allows iceberg lettuce and spinach to be zapped with radiation, to kill bacteria such as Salmonella and E. coli. Personally, I think it's a great idea. Since 1995, there have been at least 22 outbreaks of E. coli poisoning, just linked to fresh-cut lettuce or spinach. When we investigated a 2006 outbreak that sickened more than 200 people and killed three of them, I learned that even a soak in a chlorine bath won’t wipe out E. coli. Irradiation is the only thing that comes close. That and cooking, which doesn’t help your salad. Watch more from Dr. Sanjay Gupta.

Irradiation is already used to sterilize beef, spices and food packaging containers. But when I asked some friends if they'd eat irradiated food, they scrunched up their noses. No surprise to Cathleen Enright, the vice president of federal government affairs at the Western Growers Association, which represents about three-quarters of the spinach and lettuce growers in this country. I asked Enright when we might see irradiated salad in the grocery store, and she said it could be quite a while. "It's going to be a business decision, and that factors in consumer acceptance.” She herself thinks irradiation is fine, but says “[it] does make some people nervous.”

The FDA says it's safe, but consumer groups such as the Center for Science in the Public Interest say that's based on old research. They say the jury is still out, and that we’d do better to focus on having more government safety inspections, and testing produce before it goes out to stores.

Are you more worried about dangerous bacteria or radiation on top of your salad? Yum!

Editor's Note: Medical news is a popular but sensitive subject rooted in science. We receive many comments on this blog each day; not all are posted. Our hope is that much will be learned from the sharing of useful information and personal experiences based on the medical and health topics of the blog. We encourage you to focus your comments on those medical and health topics and we appreciate your input. Thank you for your participation.

By Dr. Sanjay Gupta
Chief Medical Correspondent

Ever since we had our two daughters, my wife has been insistent on buying organic milk. She looks specifically for milk free of added growth hormone, or more specifically free of rBST, recombinant bovine somatotropin. It's more expensive, sometimes more than double the price, and I was never quite sure if it makes any difference. Still, I understand her concern.

Well, Wal-Mart does too apparently. The company recently announced that its store brand milk will come solely from cows free of artificial growth hormone, which is given to cows to increase milk production. They join Kroger, Safeway, Publix and Starbucks, to name a few. The change seems to be fueled mainly by public concerns rather than specific science.

As we investigated this story, I found that most of the peer-reviewed science out there does not support a link between hormones in milk and cancer, nor with early puberty in girls, which is a widely circulated concern. Common sense, my wife tells me should prevail. "How could artificial hormones possibly be good for a growing child?" she asks the way only a mom can ask.

Often times, I am left without a response. "But, the science..." I say in vain. But, she's already off to the grocery store to buy more.

I guess the good news is that the price of milk free of growth hormones will probably come down, given the movement and more offering of this type of milk. But, still, is it worth it?

Check out an AC 360 take on hormone-free milk.

Editor’s Note:  Medical news is a popular but sensitive subject rooted in science. We receive many comments on this blog each day; not all are posted. Our hope is that much will be learned from the sharing of useful information and personal experiences based on the medical and health topics of the blog. We encourage you to focus your comments on those medical and health topics and we appreciate your input. Thank you for your participation.