有效期并非判断好坏的唯一标准

NEAL CONAN, host:

Once upon a time, we knew our veggies were safe because the greengrocer vouched for them, meat came from the neighborhood butcher, and the milk van delivered every morning. These days, of course, most of us go to the supermarket and squint at those expiration dates on the package, or maybe it's a sell-by date, or a best-if-used by date. In a piece on Slate.com food critic, Nadia Arumugam, argues that all of those dates mean very little if anything and that we are to ignore them.

How about you, can you tell us your expiration date story? Give us a call: 800-989-8255. Email us: talk@NPR.org. You can also join the conversation on our Web site, that's at NPR.org, just click on TALK OF THE NATION.

And Nadia Arumugam is a food writer for Slate, Easy Living and FLAVOURS Magazine, author of the cookbook, "Chop, Sizzle and Stir." And she joins us now from our bureau in New York. Nice to have you with us today.

Ms. NADIA ARUMUGAM (Food Writer, Slate, Easy Living and Flavors magazine, Author, "Chop, Sizzle and Stir."): Great to be here.

CONAN: And so expiration dates aren't worth the ink they're printed with?

Ms. ARUMUGAM: Well, you know, I think the problem, Neal, is that people just don't really understand what they mean. And so people get scared when they see a printed date on a pack of meat in their fridge and, you know, if come to that date and they think they going to get sick. And so they just chuck it out, you know, without a second thought. And let me tell you a little bit about this piece that I wrote for Slate and how it came about. You know, like many people, I grew up in a house where my mom would, you know, look in the fridge and see what was coming Tuesday, you know, sell-by dates...

CONAN: Mm-hmm.

Ms. ARUMUGAM: ...or use by date and just chuck it out. You know, she had four children. She didnt need any of them to get food poisoning or get sick. And she automatically assumed, like I'm sure a lot of you are listeners do, that an expiration date, you know, is essentially for own safety and we'll get sick if don't abide by them.

CONAN: And indeed that on that expiration date, that date changes into a skull and crossbones.

Ms. ARUMUGAM: Exactly. And because we don't understand what they mean, we we we, you know, we automatically attribute the worst possible scenario to them.

CONAN: And indeed you suggest that most of these dates are put on, well, rather arbitrarily - there are very few standards, and with standards, they aren't changed widely from state to states that have standards, even in some cases from city to city.

Ms. ARUMUGAM: Sure. I mean, you know, one of the things that I learnt that really amazed me was that there is no federal regulations that govern expiration dates apart from infant food and sort of baby formula. So all the dates that are being put on, you know, in your biscuits, your cookies, your preserves, they're all being decided upon by manufacturers, purely by manufacturers. And there are some laws within different states that govern...

CONAN: Dairy...

Ms. ARUMUGAM: ...dairy products...

CONAN: Yeah.

Ms. ARUMUGAM: ...for example. But again, the as you mentioned, they vary widely and, you know, for your listeners in New York City, I'm sure many of them would have noted that when they get their carton of milk in New York City has a different expiration date from the rest of the state or Connecticut or Pennsylvania. And, you know, that really confused me for a long time. And I learned that it's because, you know, New York City is the only city within the entire country that has its own laws for milk.

And it was decided upon by the New York health department in the 1950s and you know, they said that apparently at that time, it was a common practice to - of out-of-town grocery stores to resell milk that was about to expire to New York City markets and especially into the more deprived areas. And so to prevent that, they instituted that New York City had to have a more conservative date.

CONAN: Mm-hmm. I think, you know, at least, anecdotally that that's what they do to a lot of convenience stores. The convenience stores tend to have milk that's just about to expire. So I'm not sure that that's a deliberate policy, it just seems to be that way every time I go down to the (unintelligible) store.

Ms. ARUMUGAM: Sure and eventually you used the word expire and what does that mean? Does it mean that, you know, when it reaches that date that that food is, you know, suddenly become toxic to us? It absolutely doesn't. And I think that the ultimate takeaway that I got from doing all my research and reporting on this story was that, you know, we have to trust our basic human instincts. You know, food is an organic substance. And, you know, nature will tell us when it's not right to eat. And, you know, if a chicken breast in your fridge, you know, it looks like it's discolored, it has a very bad smell to it, then that's nature telling you that you need to throw it out.

You know, but if you have a chicken breast in your fridge that is a day past -you know, its use-by or sell-by date and yet you open up the pack and it still smells fresh, it, you know, it has that sort of lovely rosy hue, then again that's nature telling you that it's perfectly fine for you to cook it up and eat it.

And, you know, I spent a long time reporting and researching this story and speaking to many food scientists and food safety consultants, and the one thing that was consistent amongst them all was that, you know, they said exactly the same thing to me which is that, you know, expiration dates are conservative. And they're conservative because the people who put those dates on your food, they come by them by considering the worst possible scenario.

You know, they think about the person who has bought their meat from the grocery store, has maybe taken, you know, a long trip through town, done some shopping, gone home, maybe forgotten to put the meat in the fridge for an hour or two.

CONAN: And put it - stored it next to the light in the fridge where it gets some heat, yeah.

Ms. ARUMUGAM: Exactly. Absolutely. You know, they don't think about the most conscientious person who comes straight back from the grocery store and just put their chicken in the bottom of fridge where it's coldest.

CONAN: Mm-hmm.

Ms. ARUMUGAM: And so, you have a lot of leeway to play with.

CONAN: Our guest is Nadia Arumugam, a food writer for Slate, Easy Living and FLAVOURS magazines. Her piece on the expiration dates or the sell-by dates or the best-used-by dates appeared at Slate.com. And if you'd like to join the conversation, our phone number is 800-989-8255. Email us: talk@NPR.org. And let's go to Peter(ph), Peter calling us from Lansdowne, Pennsylvania.

PETER (Caller): Hello.

CONAN: Hi, Peter.

PETER: I have a story about...

Ms. ARUMUGAM: Hi.

PETER: ...cultured buttermilk. And our power went out one day for about 24 hours, and we had to go on vacation the next day and the power was still out. Well, we came back a week later and my buttermilk was still good even though it was out of refrigeration for quite awhile. And...

CONAN: Hmm.

PETER: ...the date doesn't really mean anything. I think it might last two months after the date.

CONAN: Well, cultured buttermilk had probably learned out to start writing symphony orchestras by then.

(Soundbite of laughter)

PETER: Well, it is cultured.

Ms. ARUMUGAM: That's a great story.

CONAN: Yeah.

Ms. ARUMUGAM: But, Peter, you make a very interesting point, which is - and, you know, that - when I think about, you know, how to advise people or suggest to people that, you know, how they can decipher whether, you know, something they take out of their fridge is good to eat or not. You know, I say to them that it's not the arbitrary date on the pack but it's the conditions in which you store your food that's actually vital.

CONAN: Right. And the fact that it has not yet approached its expiration date doesn't mean it's perfectly safe either if it stinks.

Ms. ARUMUGAM: Exactly. You know, if you...

PETER: Basically, you'd have the handling in the distribution system, as you say, is vitally important, so if the supermarket left it out of refrigeration for a couple hours, it may not last.

CONAN: Hmm. Well, Peter, thanks very much and continue to enjoy your buttermilk.

PETER: Thank you.

(Soundbite of laughter)

CONAN: Bye-bye. The interesting part also is you suggest that the kind of bacteria that develop when food gets - as you said at one point in your piece -mature in our refrigerator...

(Soundbite of laughter)

CONAN: ...on our shelves is not necessarily going to wipe out the planet.

Ms. ARUMUGAM: Right, no. And, again Neal, let me just emphasize. You know, I'm not scientist, and I went into this as a layperson to educate myself. And so, you know, I spoke to a lot of people who really understand this, and I almost wish that everyone else could have these same conversations because it -they're really enlightening.

And, you know, I do know that the difference between - there's a world of difference between a spoilage bacteria, which is - which are the bacteria that's making your food smell and, you know, turning your broccoli florets yellow, you know, and listeria and E. coli and salmonella which are pathogens and which are, you know, they are the disease-causing bacteria, and those are the lethal bacterium.

CONAN: And those are there by result of bad handling at the plant, at the...

Ms. ARUMUGAM: Exactly. And if your food is contaminated with E. coli, then, you know, you're in trouble, whether or not it's expired or not.

CONAN: Let's get Bill(ph) on the line, Bill calling us from Columbia, South Carolina.

BILL (Caller): Yes. Your guest is right on target. I have experienced both in selling food and dairy products on routes and also working in restaurants, and I learned that - basically exactly what she's saying - it's more in the way that it is handled. The average household does not invest in thermometers for the refrigerator and freezer...

CONAN: Mm-hmm.

BILL: ...and does not realize the importance that the freezer should be between zero and minus 10, and the refrigerator should be between about 33 and 36 degrees. And...

CONAN: In other words, if the ice cream is just as hard as a rock, isn't that good enough?

BILL: Pardon?

CONAN: If the ice cream is just hard as a rock, isn't that a good enough temperature indicator?

BILL: It...

(Soundbite of laughter)

BILL: That is so often the case. But what I have found, speaking of dairy products, another thing that I had discovered is that having sold dairy products and tasted them at various stages, with a dairy product, I can discern whether it is beginning to go bad because a milk or an ice cream or various dairy products, fluid products, they will begin to taste sweeter...

CONAN: Hmm.

BILL: ...in the very earliest stages that they are - that the bacteria count is going up, for a day or two, it'll be sweeter. Then, you'll feel the sting over the tongue and know that it's going bad.

CONAN: Going rancid, yes.

BILL: So you can get a little bit of a heads up there.

CONAN: Mm-hmm.

BILL: But what she said, the way it is handled is absolutely right because I keep my refrigerator and freezer at the marks that I learned in the restaurant business.

Ms. ARUMUGAM: Mm-hmm.

BILL: And I handle - if I've got to travel a distance, I have a cooler with me so that my perishables go in the cooler instead of sitting in a hot car or a trunk, and keep them at temperatures. And I have had dairy products good a month after the expiration date.

CONAN: Well...

BILL: It's all to do with the handling. And if at any - if any weak link in the chain can spoil it, and that is - it could be between the warehouse and the store, sitting on the floor in the store before it goes into the refrigerated case, mishandling in any ways can do it. So...

CONAN: And Bill, are you now in the refrigerator and freezer thermometer business?

BILL: Nope. No, but I'm a strong proponent of them because...

CONAN: Okay.

BILL: ...I do believe that they are the number one indicator or predictor of the life of food versus throwing it away.

Ms. ARUMUGAM: Mm-hmm.

CONAN: Bill, thanks very much, and we appreciate your advice.

BILL: Thank you.

Ms. ARUMUGAM: Thank you.

CONAN: We're...

Ms. ARUMUGAM: You know Neal, I wonder if I could share a little anecdote with you. You know, Bill's story reminded me of it. When I was working on this story, I happened to chance upon a yogurt that I had in my fridge. It was a vanilla yogurt. And I had forgotten about it and it was right at the back of my fridge and it was eight months after its date of expiration.

CONAN: Eight months?

Ms. ARUMUGAM: Eight months. And I hope this doesn't turn anyone's stomach. But I took it out and I opened it up and it had set slightly. And I just took a spoon and I sort of whipped it and it turned into a very smooth, fluid consistency. And I thought, you know what, this smells of vanilla. It, you know, it seems like I can eat it, so I ate it and it was absolutely fine. It tasted great.

And then a couple of days later, I had a yogurt with me that I'd taken to work and it was in my bag. And I had spent the whole day rushing around New York. I was in a subway. It was getting nice and warm in my bag, and jiggling around. And when I eventually came to eat it that evening, I opened it up and it had separated. There was a sort of strange milky fluid at the top. It was very lumpy and no amount of stirring would revive it.

CONAN: Mm-hmm.

Ms. ARUMUGAM: And, you know, I thought I'm definitely not eating this. And that yogurt was well within its shelf life.

CONAN: Yeah, probably made a wise decision. Nadia Arumugam is a food critic and freelance writer for Slate, Easy Living and FLAVOURS magazines. You're listening to TALK OF THE NATION from NPR News.

And let's go to some emails. This from Dell(ph) in Florida. If properly canned, is it true that canned foods are good for many, many years?

Ms. ARUMUGAM: Yes. You know, when I spoke to all the consultants and scientists, you know, they said that, you know, they suggested, you know, five years from the time that you purchased the canned good, there's some sort of variations, you know, if it's very acidic. Whatever is in the can is very acidic, then you should maybe use it within sort of two or three years. But canning - when you can a product, you're putting it under very, very intense heat treatment, and that will really kill just about anything, any bacteria that's inside of it.

CONAN: And no matter how old it is, if it's bulging, that's a bad sign.

Ms. ARUMUGAM: Exactly.

CONAN: Anyway, let's go to Frank(ph). Frank with us from Tucson.

FRANK (Caller): Hey, Neal, thanks for taking my call.

CONAN: Sure.

FRANK: I think refrigerators should be looked at before eight months, so that way you can find those yogurts.

(Soundbite of laughter)

Ms. ARUMUGAM: I know, but I'm sure we all know what it's like, you know? We have this refrigerator, then you have to kind of really dive in sometimes...

CONAN: Then there's those cocktail olives that have been there for decades.

Ms. ARUMUGAM: Exactly.

FRANK: Growing up - we moved here from - well, I'm in Tucson and we lived in Mexico. And my mom would always buy things. And I'm blind, so I really didn't know about dates. But my sister would always comment and say, Mom, that, you know, that sell-by date is tomorrow. And my mom would say, oh, don't worry about it, that's for white people.

(Soundbite of laughter)

FRANK: So I can't tell you how much money, you know, raising three children in a - with a small amount of money and moving to a new country, how much money she was able to save. And we all ate and, you know, I hear a lot of people talk about food poisoning, and I don't know if that's just an American concept, you know, because...

CONAN: It's interesting, are there sell-by dates in other countries, Nadia, do you know?

Ms. ARUMUGAM: There are, absolutely. And, you know, there are other parts of the world where they're much less of a sort of manufactured free-for-all. In the EU, there are - they are mandated...

CONAN: So these are all set by...

Ms. ARUMUGAM: ...by the law.

CONAN: ...rule...

Ms. ARUMUGAM: Yes, exactly.

CONAN: ...by Brussels, yeah.

Ms. ARUMUGAM: And similarly in Australia.

CONAN: Hmm. All right.

Ms. ARUMUGAM: ...as well.

CONAN: Frank, thanks very much.

FRANK: Yeah, sure.

CONAN: And let's leave with this email from Dawn(ph). She writes, several years ago, I wrote to a major food distributor, asking if the expiration dates were printed on the can of food. I got a long letter back explaining the company's use of Julian dates, which were embedded in a string of numbers on the can and how to use those to calculate the expiration date. I have a master's degree in mathematics. I was able to figure out the date. I'd venture to guess the average person would not be motivated to do this, therefore it seems that this method of displaying the expiration date is essentially useless.

Our guest, Nadia Arumugam argues, well, they're all pretty much useless. Try your nose instead.

Ms. ARUMUGAM: Absolutely.

CONAN: Nadia, thanks very much for being with us today.

Ms. ARUMUGAM: Thank you for having me.

CONAN: Nadia Arumugam is the author of the book "Chop, Sizzle and Stir" and a food writer for Slate, Easy Living and FLAVOURS magazines. She joins us from our bureau in New York.

Tomorrow, the Obama administration closes the books on the torture memos. John Yoo will be among our guests. This is TALK OF THE NATION from NPR News. I'm Neal Conan in Washington.