In 2017, the American consumer averaged 1.5 grocery shopping trips per week. While most of us focus a lot on the taste and price of our food, we might also stop to think for a moment about how the food is packaged and how it benefits everyone who grocery-shops, no matter how frequently.

Packaging — durable, strong and resistant — is one of the many reasons we have a safe food supply: It protects food. It’s also efficient and convenient for transporting food.

Let’s take a closer look at the main roles of food packaging: safety, protection, convenience, efficiency and information.

Safety and Protection

Food packaging can help extend shelf life. That means keeping food safe to eat for longer periods of time. Exposure to oxygen can cause spoilage, so some foods need airtight packaging. Losing or gaining moisture can also be a problem. You don’t want your food to make you sick, and food packaging can keep microorganisms that cause foodborne illness out.

Packaging material also has to be safe. The U.S. Food and Drug Administration (FDA) regulates them for safety by reviewing any substances that are in contact with food. Although some migration may occur over time, the levels detected are not high enough to be considered harmful.

Packaging also must protect food from being crushed or damaged — no one would dare ship eggs in a paper bag.

Convenience, Efficiency and Information

The science of packaging has made it easy for you to pick up what you need, and in the right amount. You can store your food, open the package, see what you are eating and properly dispose of it when it’s no longer suitable for use or reuse.

Packaging is also your main source of information about the product inside, such as nutritional value, ingredients and expiration date. Some packaging also carries food safety tips and cooking instructions—sometimes even a recipe for a new dish!

Packaging also helps us track foods when there is a food recall or an issue with the product that could make us sick. According to IFT’s Global Food Traceability Center, traceability allows companies to “trace products through the supply chain to improve food safety, diminish risk, avert devastating health consequences, and economic loss to the food system.” Unique barcodes on the package help track the product from one point to the next, making it possible to locate products anywhere along the food system.

Materials Used for Packaging

Packaging materials can be made from glass, metal, paper or plastic — sometimes in combination — and some materials work better for different types of food. Let’s review the basics:

Glass. Glass is the oldest packaging material, going back about 5,000 years. Its big advantage is that it is chemically inert, which provides a great barrier wall against gasses and microorganisms. It can be sterilized and is easy to reuse and recycle. The disadvantages are that glass is heavy and it breaks. Despite all the foods that you get in jars and bottles, glass only makes up about 10 percent of food packaging.

Metals. Metal packaging such as aluminum, tinplated steel and tin-free steel has been used since the 1900s. Metals also have good barrier properties. They can be heat-treated and sealed for sterility. Aluminum made into foil can be made into light, seamless cans for soft drinks. Tinplate is strong and can be used for canned drinks, processed foods and aerosol cans (like whipped cream). Tin-free steel is strongest and can be used for bottle caps and large drums for bulk-sale items.

But small particles of tin, at microscopic levels that are not harmful, can migrate into food, so it needs to be coated with sealers. Aluminum is expensive but can’t be welded, so it can only be used as seamless containers. Tin-free steel can corrode, so it to requires a protective coating. Like glass, metal also makes up about 10 percent of food packaging.

Paper and paperboard. This type of packaging goes back to the 1600s. Barrier properties of paper are limited, so to be used as a food container it has to be treated with wax, lacquer or resin. Some examples include kraft and parchment paper, which are treated to make them more resistant to water and oil.

Paperboard is used to ship food in boxes. When you include both paper and paperboard, they account for 35 percent of food packaging.

Plastic

Plastic is the newest, most versatile and most common of all food-packaging materials. It is light, inexpensive, heat-sealable and microwavable.

Plastic containers and bottles have a symbol that tells you their type, which is important for recycling purposes.

• Plastic #1 is used for water and soda bottles, as well as for products like beer, salad dressing and peanut butter.
• Plastic #2 is opaque and used for milk jugs, juice bottles and tubs of butter, as well as the liners inside cereal boxes.
• Plastic #3 is used in food wraps, water bottles and cooking oil bottles.
• Plastic #4 is used in frozen foods, bread bags and food wraps.
• Plastic #5 is used for yogurt, syrup and ketchup containers.
• Plastic #6 is made into Styrofoam, which is used to make egg cartons, cups, disposable trays and trays for meat.
• Plastic #7 includes polycarbonate plastic, which contains BPA. These are soft plastics used in many beverage containers and bottles.

As you can see, food packaging is as diverse as the foods that are inside. So the next time you’re hauling a load of groceries or just grabbing a few things from the corner store, think about food safety and how much science goes into the protecting your food, your family and your health.

This blog post was written by Chris Iliades, MD.