It’s almost impossible to imagine life without flexible, transparent and water-resistant food packaging, without plastic sandwich bags, cling film or shelves filled with plastic jars, tubs and tubes, and durable bags and boxes.
While storing food in containers dates back thousands of years, and food has been sold in bottles since the 1700s and cans since the 1800s, what might be considered the modern age of food packaging began in the 1890s when crackers were first sold in sealed waxed paper bags inside a paperboard box. Plastics and other synthetics began to appear in the 1920s and ’30s, shortly after chemical companies started experimenting with petroleum-based compounds and pioneering new materials that could be used for household as well as industrial applications.
Fast forward to 2014:
Upwards of 6,000 different manufactured substances are now listed by various government agencies as approved for use in food contact materials in the U.S. and Europe — materials that can legally go into consumer food packaging, household and commercial food containers, food processing equipment, and other products.
Recent analyses have revealed substantial gaps in what is known about the health and environmental effects of many of these materials and raised questions about the safety of others. A study published this past July found that 175 chemicals used in food contact materials are also recognized by scientists and government agencies as chemicals of concern — chemicals known to have adverse health effects. Another published in December 2013 found that more than 50 percent of food contact materials in the U.S. Food and Drug Administration database of such substances lacked accompanying toxicology information filed with the FDA about the amount people can safely eat. This database is publicly available and searchable, but the database itself doesn’t include toxicology information about these substances or any details of the products in which the listed chemicals are used.
Presumably, the primary goal of food packaging is to keep food safe to eat. But what do we actually know about the stuff that surrounds our food? What do we know about how these materials may interact with the food they touch, or their potential effects on human health and the environment?
Plastics, Coatings, Colors, Glues
In the U.S., the FDA regulates food contact materials, classifying them as “indirect food additives.” These materials, which fall under the jurisdiction of the Food Drug and Cosmetic Act, include not only the polymers that make up plastics but also resins and coatings used in can linings and jar lids, pigments, adhesives, biocides and what the FDA charmingly calls “slimicides.” The FDA distinguishes these substances from those added to food itself by explaining that food contact materials are “not intended to have a technical effect in such food,” meaning that these substances are not supposed to change the food they touch.
This categorization makes such substances exempt from food ingredient labeling requirements, explains Dennis Keefe, director of the FDA’s Office of Food Additive Safety. In other words, food packaging need not carry any information about what it’s made of. Any such information is voluntary, often geared toward facilitating recycling and sometimes part of marketing campaigns declaring a product “free of” a substance of concern.
“Food packaging chemicals are not disclosed, and in many cases we don’t have toxicology or exposure data,” explains Maricel Maffini, an independent scientist and consultant who specializes in food additives research. Yet a core component of the FDA’s regulation of food contact materials is based on the assumption that these substances may migrate into and be present in food.
In fact the FDA’s system for approving food contact materials — which it does on an individual basis, with approval granted to a specific company for a particular intended use — depends on how much of a substance is expected to migrate into food. This is assessed based on information a company submits to the FDA; the FDA may come back to a company with questions and do its own literature search, but it doesn’t send the substances to a lab for testing as part of the approval process. The higher the level of migration, the more extensive toxicological testing the FDA requires.
In addition to the materials themselves, Muncke explains, these substances’ chemical breakdown and by-products need to be considered.“We’re talking parts per billion,” explains George Misko, partner at Keller & Heckman, a Washington, D.C.–based law firm that specializes in regulation. But that’s a level at which some chemicals used in food packaging have been found to be biologically active.
Beyond the Container
But there’s “more than the threshold of migration” that needs to be considered when assessing food contact material safety, says Jane Muncke, managing director and chief scientific officer of the Zurich-based nonprofit Food Packaging Forum. In addition to the materials themselves, Muncke explains, these substances’ chemical breakdown and by-products need to be considered. This means that there are lots more individual chemicals that may be touching food — and therefore be detectable in food — than those present in the packaging as formulated. For polymers — the large molecules that typically make up plastics — these breakdown and by-products “can be significant,” says Muncke.
While food contact materials are not intended to alter food, they are not necessarily inert or biologically inactive.These additional breakdown and by-product chemicals also contribute to issues of chemical safety assessment, explains Maffini. Chemical regulations typically consider chemicals one at a time, when in reality we’re exposed to multiple chemicals concurrently, including those present in food. So the individual chemical assessments that determine food contact material approvals may not capture all the ways in which a single substance may interact with food, human bodies or the environment. The list of chemicals measured by the U.S. Centers for Disease Control and Prevention’s National Health and Nutrition Examination survey offers a snapshot of this issue. It includes in its biomonitoring (testing for chemicals in the human body) not only whole chemicals to which people may be exposed, but also numerous compounds that occur only after these chemicals enter and are metabolized by the human body.
As Muncke and other scientists have pointed out, while food contact materials are not intended to alter food, they are not necessarily inert or biologically inactive. This is where the parts-per-billion levels that trigger the FDA’s testing levels for food contact materials quickly gets complicated.