NUTRITION

Keeping Food Safe to Eat

P E G G Y K L O S T E R Y E N

Elderly Jane Baker is inspecting a can of stewed tomatoes, a favorite of hers, that costs 25 cents less than usual because the can is dented. Should she buy it?

And what about John Rober t? Four hours ago he went to a great picnic at the senior center---chicken salad, fruit, milk, and apple pie. Now he feels nauseated and has a s tomach ache and diarrhea. Ju s t in- digestion? The flu? Or maybe food poisoning?

Older adults s h o u l d bo concerned about whether their food is fit to eat. S u m m e r is almost here, which means an increase in illness caused by food-borne bacteria. About two million cases a year is the est imate.

Elders who are malnourished or have a chronic disease h a v e a n o t h e r reason to be concerned. Fluid and electrolytes lost through the diarrhea and vomiting of a bacterial illness can seriously threaten their health.

The way food is handled af ter it leaves the processing plant can make the difference between safety and danger. Mr. Robert ' s chicken salad might have been contaminated by the staphylococci in a d ie tary work- er 's sneeze or skin lesion. At room tempera ture , especially on a warm day, staph multiply rapidly. Suscep- tible foods, especially mea t and pre- pared foods, become hazardous af ter two to three hours at tempera tures above 60 ° F. The warmer the air, the faster the spoilage, even though the appearance of the food may not change.

Cont ra ry to popular opinion, the mayonnaise in the chicken salad is not the culprit. In fact, salt and acid ingredients like lemon juice actual ly slow bacterial growth in mayon-

Peggy Kloster Yen, RD, MPH, is a consultant and writer on the management of nutrition in

naise. So mayonnaise in food helps retard spoilage, not promote it.

Damaged Cans

Food can become dangerous to the consumer in m a n y ways. The dent in Ms. Baker 's can of tomatoes could have broken a hole that let in bacte- ria. I f the dent is so small that it barely disfigures the can, the food is probably safe to eat. But badly dented cans or cans that are bulging or leaking may be carriers of botu- lism, a potential killer. Caution el- ders to discard the food without tast- ing it. Advise them not to store cans that bulge because they were acci- dentally frozen. The food can be used, however, if it is removed and cooked immediately.

Most people do not eat food that smells or looks peculiar, such as hot dogs in cloudy liquid or meat with offensive odors. But food-poisoning bacteria, most commonly the staphy- loccus, don ' t always show themselves this way. There are also salmonella and C l o s t r i d i u m per f r ingens .

Salmonel la causes more severe symptoms than staph and elders are more seriously affected than young- er persons. The risk of saimonellosis is one reason that most ins t i t~ ions don ' t serve any food that contains raw eggs. Raw or undercooked poul- try, eggs, and mea t are the usual source of salmonella. For this reason, advise elders not to tlJace raw mea t and poultry on a cutt ing board or any surface where other foods are prepared. Also, it 's important to wash the plat ter that held the raw chicken before putting the cooked chicken back on it.

Safe Holding Temperatures

Food safety is a mat te r of de- g r e e - F a h r e n h e i t , that is. C. pe r - f r i n g e n s is called the cafeteria germ because it is often found in food held in s team tables or left at room tem- pera ture for long serving periods.

Cooling cooked food to room tem- pera ture before refr igerat ing it en- courages the growth of perfringens. This procedure may save electricity, but it risks illness.

Keeping foods at safe holding tem- peratures is a leading problem for in- sti tutional and group-feeding pro- grams. The New York Office for the Aging investigated the potential for bacterial growth in the s ta te 's home- delivered meals.

The tempera ture of food was mon- itored directly from the t ime it was prepared to the t ime it arr ived at the par t ic ipants ' homes( l ) . These tem- peratures fluctuated widely, depend- ing on the packaging and t ransport sys tem used. ? icnic- type chests were the least effective in mainta in ing hot food temperatures safely above 140"F, Supplemental heat sources added to transport chests should be placed under, not over, the meals to ensure heat retention, the study found. Also, portioning and loading meals rapidly is essential because this is the step where the most heat is lost.

The investigators concluded that home-delivered meals are frequently held at temperatures that favor the growth of pathogenic bacteria. For- tunately, most deliveries took 90 minutes or less, too short a t ime for significant bacterial growth. But the potential for problems still exists. Bad weather or vehicle breakdown

c o u l d delay delivery. I f recipients don ' t eat the meal immediately, there is more t ime for organisms to multiply.

Food service programs for seniors, the study pointed out, can prevent food poisoning by taking these pre- cautiohs:

• Store refr igerated foods at 34"F to 40 ° F.

• Store frozen foods below 0* F. • Do not refreeze or eat frozen

foods that have thawed to room tem- Continued on page 166

NUTRITION

Cont inued f r o m page 164

perature . • Refreeze or refr igerate part ial ly

thawed food only if it still feels cold or has ice crystals on it.

• Keep in mind that part ial thaw- ing and refreezing can affect taste and texture as well as make foods less appeal ing and nutritious.

• Mainta in cooked food above 140°F until consumed, to ensure safety. This can be difficult when the heat source is under the food that ' s open to the air during a serving peri- od, as with a warming tray, chafing dish, or s team table.

Crockpots and Microwaves

The populari ty of slow-cookers raises some questions. In a crockpot, food takes about two hours to reach the safe temperature , 140" F. Frozen food takes much longer. I t ' s best to thaw it completely before placing it in a erockpot.

Overloading the cooker leaves some food too far f rom the heat source to cook thoroughly, so keep portions small. Reheat ing leftovers in a crockpot takes two hours at pos- sibly unsafe temperatures , so reheat leftovers on the stove.

The microwave oven m a y under- cook pork, increasing the risk of trichinosis. Researchers found that the surface of pork roasted in a mi-

crowave oven never reached a tem- perature that kills the Trichinella spiralis larvae, the parasi te responsi- ble for trichinosis.

Because microwave cooking pro- duces no heat inside the oven, foods are actual ly cooler on the surface than inside. Solve this problem by placing pork in a cooking bag before it goes in the microwave oven(2).

Food Spoilage vs. Food Poisoning

Food poisoning is a serious threat. But what about s torage and cooking methods that change the quali ty and nutrit ional value of food? Canned food, for instance, seems indestruc- tible, but it doesn' t keep forever. Low-acid canned goods like stews, soups (except tomato) , potatoes, corn, and others, will keep for two to five years. High-acid foods like to- matoes and many fruits should be used within 18 months. These foods react chemical ly with the can, alter- ing taste and even nutritional value.

Older people, who often stock up on canned goods to save trips to the store, can be encouraged to date cans as a way of ensuring quality. The ideal is to use canned foods within a year.

Leaving food in open cans is not a good pract ice. Lead may leach into the food f rom the seams of some cans. Foods can develop a metal l ic

taste. To reduce vi tamin loss, advise elders to keep high-vi tamin-C fruits and juices in tightly covered contain- ers.

R e c o m m e n d these other buying, cooking, and storage pract ices that preserve food quality:

• Cut foods shor t ly before using them so that prolonged exposure to the air does not reduce vi tamin con- tent, especially vi tamin C.

• S t eam vegetables or cook in the least amount of water possible. El- derly housewives may r e m e m b e r the days when canned vegetables were boiled endlessly to reduce the risk of botulism. This risk is a lmost nonexis- tent with modern commercia l can- ning methods. Lengthy boiling af- fec ts v i tamin and mineral content as well as texture.

• Package foods for the freezer by sealing in mois ture-proof wrap. Freezer burn, a whitish discoloration seen on meats a n d other foods, causes poor flavor and some nutrient loss.

• Keep fresh fruits and vegetables only a few days, especially at room tempera ture . Fresh spinach loses 50 percent of its vi tamin C af ter two days ' s torage at room tempera ture .

• I f possible, use a refr igerator that has a freezer with a separa te door, and maintain t empera tu re at 0 ° F or below. Tempera tu re s in a freezer compar tmen t tha t ' s not a separa te unit cannot go below 10"F without freezing everything in the~ refr igerator .

• Buy foods that are solidly fro- zen, not part ial ly thawed.

The quality and variety of food avai lable in supermarke ts is excel- lent. Elders can eat well by shopping there and by handling food in a safe way. Institutions where food is pre- pared for seniors are responsible for ensuring the quali ty and safety of the food they provide by storing, pre- paring, and serving it properly.

References 1. Study examines HDM time/temperature. Ge-

rontoI.Nutr.Diet.Pract.Group Lett. pp. 10-14, Dec. 1984.

2. Greenberg, R. A. Taking the trichinosis hazard out of microwave-cooked pork. ACSH News Views 5:3. Sept.-Oct. 1984.