PD_Fitness and WellBeing_67061 Early Bird specials, condo board spats, Monday night mah-jongg, even a brand new car bought for them by one of their sons—Shirley and Ray Lindner are living out a long, loopy Seinfeld episode at a retirement community in Delray Beach, Florida.

It's worlds away from the offices of the US Department of Agriculture (USDA) and the Food and Drug Administration (FDA), where government officials have declared that elderly people should not eat certain foods. The concern is that these foods might harbor Listeria monocytogenes, a type of bacteria that can cause serious illness and even death in those beyond middle age. Among these foods: smoked salmon (aka lox, served every month at the Men's Club meeting) and smoked whitefish, found in many people's refrigerators.

"I never heard this," said Shirley, my mother, who turned 73 last week. "We eat these things all the time."

They, their neighbors, and older people all over the country probably eat a number of foods the government wants to dissuade the elderly from having to decrease the incidenes of foodborne illness. The off-limits list includes everything from deli meats to soft cheeses to refrigerated pates, raw oysters, alfalfa sprouts, fresh (unpasteurized) juice, eggs cooked sunny side-up, and Caesar salad dressing made with raw yolks and whites.

While Listeria may be the culprit that renders certain foods risky, some may have Salmonella, while others could contain E. coli, Vibrio vulnificus , or other bacterial pathogens. But since the immune system declines with age, fighting off any of these infectious "bugs" could be much more difficult for an old than for a young or middle-aged adult, who might end up unscathed, or at least with nothing worse than some passing diarrhea or a low-grade fever. You've seen the warnings: "...can cause serious illness in children, the elderly, pregnant women, and persons with weakened immune systems."

According to the Centers for Disease Control and Prevention, in the US, more than 300,000 people are hospitalized and 5,000 people die each year from foodborne illness.

Who, Exactly, Are the Elderly?

My father, age 74, can still beat me at tennis as well as out-swim me. My mother walks two miles a day, keeps her house eat-off-the-floor clean, and is out socializing more evenings than I am. Both punched their chads all the way through. Most of their friends, as far as I can tell, are also none the worse for their smoked salmon penchant.

In a document issued jointly by the USDA and the FDA, the cutoff point for "elderly" is given as 65. But a separate FDA document says that "we haven't defined what is meant by the term `elderly' or `senior.'" Neither have many health care professionals.

"As far as I'm concerned, the definition of elderly moves up every 12 months," says David Acheson, MD, director of the Food Safety Initiative at Boston's New England Medical Center. "Arbitrarily, people have said over 65," he observes. "But there are a lot of 66-year-olds who would say, "Gee, I'm not old."

Bessie Berry, manager of the USDA's Meat and Poultry Hotline, is one of them. "I bristle at the term `elderly,''' she says. "I'm beyond 70 myself, but I don't fit that group. I don't feel frail, and I don't feel elderly." And, she says, "I still take chances. If I were on chemotherapy or had AIDS, what I would eat would certainly differ, but I consider myself reasonably healthy even though I fit into an age group that is identified as the elderly."

Irwin Rosenberg, MD, director of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, wouldn't shy away from the likes of soft cheese or alfalfa sprouts himself. Robust at 66, and a regular participant in such activities as cross-country skiing, biking, and ]]>kayaking]]> , he eats pretty much whatever he wants.

"What is considered elderly is at best a moving target—which is getting older," Rosenberg says. "When the World Health Organization talks about older persons, they're talking about 65. But when people talk about the elderly, I think they're usually talking about 75-plus or 80-plus. I don't think anybody can give you an exact number."

Immunity Declines With Age

Not that Dr. Rosenberg believes everybody who is 65 is as safe from foodborne illness as, say, the average 45-year-old. He notes that as many as one in five people over 60 (and two in five over 80) are estimated to have atrophic gastritis, a condition of insufficient stomach acid that could make it easier for harmful bacteria to survive the journey through the GI tract. The immune system starts to lose efficiency at a certain point, too. But the rate at which that happens differs from person to person. There's no way of knowing for certain who is going to be affected when—or how strongly.

Dr. Acheson would agree. "Not everybody's immune system is going to deteriorate at the same rate," he comments. "You could be a 60-year-old who has a lousy immune system or an 80-year-old with a great immune system. Different people lose their ability to fight infection at different rates. It's an unpredictable decline."

So how do you know if you're among the "elderly" whose immune system has weakened to the point that you should take extra precautions when it comes to food safety and listen to the government's alerts?

"People's immune systems don't get tested one by one," Dr. Acheson says, so it can be hard to tell. However, he comments, "if you find that you're getting infections that you didn't used to get, that would be a clue." He also notes that no matter how healthy you feel, "as one gets older there should be an appreciation that your susceptibility to infectious diseases goes up and your ability to fight them goes down."

Considering Your 65th Birthday? Consider These Foods More Carefully.

Simin Meydani, DVM, a professor of nutrition and immunology at Tufts, takes a more hard-line stance. While she acknowledges that "some older individuals could have a better immune response" than others, "in general, the immune system has started not to function as well" at 65. Even someone who feels healthy and looks physically fine is assuming more risk than might be reasonable by eating such items as raw shellfish, runny eggs, and the like.

Risk—specifically, how much you're willing to assume—is what it comes down to, of course. But no one can give you odds.

So as you enter your 60s, 70s, and 80s and the immune system declines, it's wise to consider a little more carefully whether the food you're eating could put you at risk for an infection from harmful foodborne bacteria. The frail elderly in nursing homes or with vulnerable immune systems because of, say, chemotherapy to treat a cancer, obviously have to be careful about what they eat. But the well elderly should make conscious, informed decisions about food safety, too. Taking a calculated risk—or opting for zero risk, as the government advises—is better than ignoring risk altogether.

Give thoughtful consideration to the following foods:

Uncooked, refrigerated foods — soft unpasteurized cheese such as feta, Brie, Camembert, blue-veined and Mexican-style varieties; deli meats and other ready-to-eat meat and poultry products; smoked fish, such as smoked salmon; refrigerated pates and meat spreads
All of these foods can contain a type of bacteria called Listeria monocytogenes . Cooking kills the harmful microorganisms, but none of these foods are eaten heated. The bacteria can cause everything from flu-like symptoms to meningitis, a life-threatening inflammation of the membranes that surround the brain and spinal cord. These days it’s becoming more common to find certain soft cheese, however, such as feta, that have been heat-treated through pasteurization.

Foods made with unpasteurized raw eggs — Caesar salad dressing, hollandaise sauce, egg nog, key lime pie
Raw, unpasteurized eggs (as opposed to the eggs in bottled Caesar salad dressing, for example) may contain Salmonella bacteria, which can bring on nausea and diarrhea but can also lead to serious complications such as severe dehydration. Runny eggs and sunny sides-up can contain Salmonella , too. Eggs that are runny aren't exposed to enough heat to kill the bacteria that may be present, and sunny sides-up would need to be flipped over (and become plain old fried eggs) to make sure the bacteria are killed on both sides.

Raw mollusks — oysters, clams, and mussels
These foods sometimes contain Vibrio vulnificus or Vibrio parahaemolyticus , which could cause everything from severe dehydration to stomach cramps to fever to blood poisoning. People who may have low stomach acid (the case with three out of 10 elderly people) are particularly vulnerable and should never eat raw mollusks, even if they come from a reputable restaurant or fish dealer.

Alfalfa sprouts
These curly vegetable "threads" that often appear atop salads or tucked into sandwiches can contain the same bacteria that make undercooked burgers a risk for everyone: E. Coli 0157:H7 . Bean, radish, and mung sprouts may pose a risk as well, according to the FDA. The high level of moisture sprouts need to grow provides the perfect environment for bacteria to thrive, and since the sprouts are typically eaten raw, the pathogens—which can cause kidney failure—don't get killed during cooking. Washing thoroughly doesn't rid them of all the bacteria, either.

Fresh (unpasteurized) juice — from a roadside stand or juice bar
About 2 percent of the juice in this country is sold unpasteurized, meaning that it has not been treated to kill harmful bacteria, including E. Coli . It causes an estimated 50,000 annual cases of foodborne illness, ranging from diarrhea and stomach cramps to much, much worse.

Despite the uncertainties, Tufts's Dr. Rosenberg and the USDA's Berry are going to continue to take their chances. So are my parents. The white fish and smoked salmon stays; there's no question on that score. And they'll enjoy a slice of key lime pie made with raw egg if they feel like it. Which leaves, in the end, only the age-old query:

"So when are you coming down to visit?"