Ask Professor Produce

Why are the greens and lettuces always kept so wet? -Tom, Minneapolis

Warning! Hard truth comin' at ya: All the items in the produce aisle are dying - sad but true. Those crunchy, fresh greens might seem lively and ready to leap into your grocery cart, but no, they are going "gentle into that good night." Stand in front of that wall of green leafies in the produce aisle some time and you can almost hear their last, final breaths (called "respiring" aptly enough). These poor veggies have been pulled from their soil, cut from their roots, put in dank boxes, and shipped across the country in that refrigerated hearse called a produce truck. Man, it's enough to make you start eating meat, eh?

So to help them rage, rage against the dying of the light, we dunk our lettuces and greens in water upon their arrival. Our refrigerated display case has circulating air, which keeps the case from getting moldy but also dries out the leafies considerably. So we keep the leafies fresh and beautiful with continual misting and with trips back to the sinks for further rehydration. Believe me, if we didn't do this, that display would look like a withered compost heap.

And how do I prevent my lettuce from going bad if you keep them so wet? -Tom, Minneapolis

If you store your green leafies as wet as we keep them in the display, you're right, Tom, they'll go bad very quickly. So when you get them home, unbind your greens/lettuces and spin them in a salad spinner, or otherwise get the water out before storing them. Put a paper towel in the bag (this will absorb excess water while still providing humidity), and then squeeze out the excess air before sealing. Keep your greens in the crisper, out of your refrigerator's airflow, or you'll have the same problem we have with our refrigeration.

On a side note, many of our customers swear by Evert Fresh bags over which death apparently holds no dominion. These bags, sold in the Produce Department, absorb the ethylene that fruits and veggies give off as they "respire" (that is, decay/ ripen). A crack team of researchers in Professor Produce Laboratories recently placed one head of green leaf lettuce in an Evert Fresh bag and another in a regular plastic bag, and then refrigerated them for a week. The lettuce in the Evert Fresh bag looked freshly harvested (after a week!), while lettuce in the regular plastic bag had pockets of rot shot through it.

I heard that the U.S. postal service now wants to irradiate all of our mail as a result of the anthrax outbreaks last fall. What do you think? Isn't this just a ploy to make irradiation more acceptable to the public? -Mike, Oakdale

You bet, Mike! The Atomic Energy Commission wants us to think, "Hey, if irradiation is safe enough for my mail, then why not zap my food too?" But for that strategy to work, the U.S. Postal Service must provide a glowing (ha ha) testimonial supporting irradiation's use against anthrax - and they're less impressed with irradiation now that they've actually worked with it.

A bit of background. The company Surebeam, and the rest of the irradiation industry, hit the media with a pro-irradiation spin campaign right after the anthrax postal attacks last October, claiming that irradiation was the answer to our bioterrorist problems. The U.S. Postal Service took the bait, because they were swimming in undelivered letters and a growing perception that the mail was dangerous. The backlog of mail that had piled up in the contaminated Brentwood, New Jersey post office was huge, but by mid December all of it had been irradiated in Ohio by Surebeam machines purchased to the tune of $40 million. But seven weeks after postal officials began using electron beam irradiation, according to The Chicago Tribune, the process burned, discolored and delayed too many letters for postal comfort.

"It is not as easy to use as we anticipated," said USPS spokesman Jim Mruk. "We need to look at something other than irradiation. It isn't going to be enough."

Part of the problem is the outcry from people sending edible/living products through the mail. After citing wildly varying studies to the public, the U.S. Postal Service decided to zap the mail at 20-25 kiloGrays (roughly equivalent to 700 million chest x-rays), saying that "most" strains of anthrax die at 20 kiloGrays. But no one stopped to think about food-by-mail. The USDA maximum irradiation dosage allowed for fruits and vegetables is 1 kiloGray. That means if you sent oranges, nuts, or fruit cakes through the Eastern Seaboard's mail this Christmas, they might have received 25 times the allowable dose of irradiation. Merry freakin' Christmas.

When confronted with this, USPS officials said that e-beam technology is only effective up to an inch and a half of penetration. So as long as there was a good amount of packing material between the irradiating e-beam and the contents, the food was safe. To which the Professor says, "huh?" (A) Who the heck was supposed to know that? And (B) if bioterrorists decide to package up their "special deliveries," won't anthrax survive e-beam, too?

With these logical gaps (to say nothing of the 90 pounds of mail that burned on a jammed conveyor belt while it was being e-beamed), it's no surprise that the U.S. Postal Service now intends to explore other options and to cut their $175 million loss. For deadly bacterial outbreaks, irradiating the mail will certainly continue, but on a hot zone by hot zone level. So that round goes to the irradiation industry for finding a solid, practical application for its product. But for widespread usage in "mail sanitation," obviously different technology must come to the fore, and the Postal Service is backing away from e-beam irradiation as a result.