Battling Bacteria at the Grocery Store

Scientist Urvashi Rangan brings a cooler bag when she shops for groceries. And she thinks you should, too.

Most people know that food needing refrigeration should not be exposed to warmer temperatures for more than two hours. Yet for many shoppers, the grocery store is just one stop on a series of errands.

You put yourself and family at risk if you're leaving food, especially meat, dairy and fresh produce, exposed for too long, experts say.

"Once something is contaminated, bacteria can grow very quickly under certain temperature conditions," said Rangan, senior scientist with Consumers Union, the nonprofit publisher of Consumer Reports.

Bacteria can thrive at temperatures between 40 and 140 degrees Fahrenheit. An ice chest or bag can help keep your food from becoming a breeding ground for contaminants.

There are an estimated 76 million cases of food-borne sicknesses each year in the United States. Most cases are mild and cause symptoms for a day or two, according to the Centers for Disease Control and Prevention. Common symptoms include diarrhea, vomiting and cramping, though the condition is more serious for those with a compromised immune system.

A string of food contamination outbreaks in the past year has grabbed headlines, and reignited concern among consumers. Yet shoppers may still be surprised about some sources of problematic food, and how easy it is to spread contamination. No food is completely safe as each step of the preparation process, from the farm to the table, presents an opportunity for contamination.

Just in the past few weeks alone, the Food and Drug Administration told consumers not to eat certain brands of green beans because of a threat of botulism, a life-threatening illness. Canned hot dog chili sauce and dog food have also been recalled recently due to the risk of botulism toxin.

Among other contaminants, raw and undercooked meat and poultry can contain E. coli and Salmonella; produce and contaminated water can contain bacteria, viruses and parasites, while raw and undercooked shellfish can contain the Vibrio bacteria, according to the National Institutes of Health.

Salmonella is also found in homemade foods such as sauces, dressings and ice cream, while botulism spores can exist in improperly canned goods.

The most commonly recognized food-borne infections are caused by the bacteria Campylobacter, Salmonella and E. coli, and Norwalk and Norwalk-like viruses, according to the CDC.

Here are some tips for consumers to make sure they adopt best practices for shopping and food preparation:

Baggies are your friend

At the grocery store, make sure to double bag meats, and keep using bags even in your cooler.

The bags will help to prevent cross contamination by containing any juices that can leak from the thin plastic wrap. If you don't see plastic bags near the meats, head back to the produce section and snag a few.

Fresh produce also needs baggies, experts agree. You want to protect the produce from any meat or poultry juices. Also, if you are among the many consumers who place delicate produce in the child seat of their shopping cart, consider this: How frequently do you think those seats, which cradle diapers throughout the day, are washed?

Looks aren't everything

Bacteria are so small, contamination often can't be seen. But, the smell test can help for products such as milk.

When it comes to fresh produce, choose products with less damage, bruising and punctures. The skin of produce such as apples and cucumbers provides a barrier to contamination, says Michelle Smith, a scientist with the FDA's food safety office.

"The worst kind of damage would be a wound that would allow pathogens into the interior," she says.

However, she noted, bruised or otherwise damaged goods don't necessarily contain pathogens. Besides, perfect pears, a particularly delicate item, can be pretty hard to find. In that case, Smith recommends simply cutting away the bruised area.

For products without a tougher outer layer, such as spinach or lettuce, consumers should peel the outermost leaves to remove contamination,

"If there's contamination there, it's most likely to be on outer layers," Smith says.

Washing produce can remove surface residues and pathogens present in soil that may still be attached to a fruit or vegetable, she says. While you can't completely eliminate the chance of contamination, you can "reduce the likelihood" of getting sick, Smith says.

Consumers don't necessarily need to wash bagged salads, which Smith herself eats.

Strategize your shopping trip

Sam Beattie, a food safety extension specialist at Iowa State University, says he takes trips to the grocery store as a solo mission, or hits the grocery store at the last minute to protect perishable foods.

When you get to the grocery store, look at its layout, and figure out how to make sure that you pick up meats and dairy last, Beattie recommends.

Also, look at the meat display cases, and determine whether the meat is stacked so high that it is no longer being refrigerated, Beattie says. Check for a load limit line on the meat case that should indicate the correct level for food to be displayed.

Best practices continue at home

Just as you wouldn't want the local market to store meats and produce together, it's important for you to use the separate bins in your refrigerator. Here are expert tips for food safety at home:

The back and bottom of your fridge tend to be the coolest places, so choose those areas to store meat and dairy. Continue to use plastic bags in your fridge to prevent cross contamination.

Use a meat thermometer to ensure your food is thoroughly cooked. Heating food to an internal temperature above 160 degrees F. or 78 degrees C. kills most parasites, viruses or bacteria. However, botulism spores are killed only at temperatures above boiling. Regular soap (it doesn't have to be antibacterial) will reduce contaminants on your hands.

Pay particular attention to areas under your fingernails and rings, and rinse up to your wrists. After washing, dry your hands with a paper towel, rather than kitchen cloth towel that may be teeming with bacteria.

Sanitize countertops with a mixture of a teaspoon of chlorine bleach and a gallon of water. This method also works for cutting boards. Use a cutting board without cracks or nicks for food preparation.