Article originally from American Chemistry magazine.

Innovations born from chemistry currently protect this country’s food supply at many stages, from pest-free crops through vacuum-sealed packaging to corrosion resistant refrigerator liners. True safety for the consumer, generally, is a matter of conduct within the kitchen—whereby chemistry again helps get the job done.

Cleaning

Harmful foodborne bacteria—including E. coli, Salmonella, and Listeria—can lurk on various kitchen surfaces and in the refrigerator, so it is critical to keep them clean and dry. This entails regular washing with hot, soapy water.

Added protection for kitchen surfaces can be provided by using a mixture of one teaspoon of liquid chlorine bleach per quart of water. The surface should be flooded with the solution, allowed to stand for several minutes, rinsed, and air-dried or patted dry with paper towels. This is suitable not only for countertops, but also for the kitchen sink, including its drain and disposal system. 

This tactic should not be attempted in the refrigerator, however, where chlorine bleach can damage seals, gaskets, and linings. Also, bleach and detergent should never be used to clean food, as they are not safe for consumption.

Cutting boards can also gather bacteria. One way to avoid this problem is to use dishwasher-safe plastic cutting boards or disposable cutting sheets.  It is a good idea to use separate boards for meat and produce.

Dishcloths and towels can harbor and, when wet, promote the growth of bacteria. They should be disinfected frequently in the laundry, using the hot water cycle of the washing machine. 

Storage

Storing foods in sealed plastic containers or using plastic wrap will keep them fresh and help avoid foodborne illnesses. A permanent marker and labels can be used to add the date, which can be checked thereafter to ensure foods are still safe to consume.

Foods spoil due to oxygen, so it is essential to seal plastic lids tightly and squeeze the air out of sealable plastic bags. Plastic wrap also helps limit the transfer and loss of odor and flavor.

Meat, fish, and poultry can be marinated in heavy-duty sealable plastic bags to enhance flavor, keep contaminants away, and minimize cleanup time.

To keep herbs fresh, they can be placed upright in a glass half-filled with cool water, then covered loosely with a small plastic bag and set in the refrigerator.

Microwave cooking

When food is properly packaged and stored, plastics work well with microwave ovens to prepare meals in minutes. Plastic is often specially designed with the appropriate flexibility and heat resistance for this purpose. However, with many plastics serving many different needs in the kitchen, it is easy to get confused about which are safe for microwave use.

One straightforward step is to follow the instructions for the meal. Most prepackaged foods come with directions indicating whether the user should remove some or all of the plastic wrap or cut slits in it. If there are no such instructions, he packaging should be discarded and the food prepared in a microwave-safe plastic container.

Plastic wrap helps trap heat and moisture, so food cooks evenly and thoroughly. It also prevents splatter. However, proper use is important, as plastic wrap can melt if it is allowed to come into contact with extremely hot food. Plastic wrap is not heated by microwave energy, but can be through such contact, particularly with high-fat foods like butter. Therefore, the wrap should cover the dish without touching the food.

All plastics intended for use with food must meet stringent U.S. Food and Drug Administration (FDA) safety standards before they are allowed on the market.  When individual plastic packaging products are developed, manufacturers often conduct additional testing based on intended use.  Choosing to microwave with a plastic item not labeled for that purpose is not necessarily unsafe, but there is no assurance of knowing that the item was tested and evaluated for such use. 

Do not use plastic containers for cooking unless they are intended for that purpose.  Many containers in which food—such as butter or cottage cheese—is sold are designed for cold storage, not cooking or reheating.

Some items are labeled as ‘microwave safe,’ carry a microwave symbol, or provide instructions for safe microwave use. They all indicate a container has been designed to withstand a microwave oven without melting or warping.

Symbols that identify the type of plastic in a container do not themselves indicate microwaving suitability. Some packages made of polyethylene terephthalate (PET), for example, are fabricated for high heat resistance, while others are not and could warp.

It is worth noting an e-mail hoax has circulated the Internet for years, alleging microwaving food in plastic containers releases dioxins. This is not true. While dioxins can be produced by combustion at very high temperatures, the vast majority of plastics used with food do not contain the chemical constituents necessary for that process.

“We have seen no evidence plastic containers or film contain dioxins and we know of no reason why they would,” says the FDA.

Also, microwave ovens do not generate sufficient heat for the process, as dioxins typically form at temperatures above 700° F.

Lunch boxes

Another recent rumor suggested children’s vinyl lunch boxes posed a health hazard due to lead content. The U.S. Consumer Products Safety Commission (CPSC) responded to this concern last year, reporting that tests indicated there was no such hazard.

“The staff tested the inside and outside of each lunch box and the preliminary results were consistently below one microgram of lead,” said the report. “This is an extremely low level and would not present a health hazard to children.”

The independent federal agency, which can recall products when necessary, used certified laboratory test procedures to reach its findings.

“Based on the levels of lead found in our tests, in some cases, children would have to rub their lunch box and then lick their hands over 1,000 times a day for 15 to 30 days for the lunch box to present a hazard,” said a CPSC release in September 2005.

Future of food

Innovations continue to develop from chemistry to help consumers keep a safe kitchen. Atmosphere-controlled packaging extends the shelf life of produce, but plastic films in the future will also be designed to control the growth of microorganisms, which could extend the life of cheese and meats.

Plastic packages that change color to let the user know the food inside has gone bad are also being developed. This feature will use sensor-based technology.

Time and temperature indicators are self-adhesive labels that are already used for this purpose in the pharmaceuticals industry.  They are starting to make inroads into the grocery industry today. For example, they appear on ‘Meals Ready for Eating’ used by
the U.S. Army.

With files from the Plastics Division of American Chemistry Council (ACC). For more information, visit http://www.plasticsinfo.org.

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