Recently, CEH was asked for our take on safer materials for cookware and other kitchen items. To respond, we compiled information from a wide range of sources– but as with many consumer products, we found that for the most part, there have been few or no independent studies on most types of kitchenware, and even less research on the life-cycle of the products. But some of what we found may surprise you. Read on for tips on keeping your kitchen and your food safer from toxic chemicals.
Consider a wooden bamboo straining spoon, sourced from a sustainable producer who works with small, local growers and third-party organic, Fair Trade certifiers (see “wood” section, below). Compare that to a plastic slotted spoon, which carries impacts from the use of unsustainable petroleum plastics, health impacts on workers in and communities around plastic manufacturing plants, potential health issues to consumers from chemicals that leach from plastics, pollution from landfills and other disposal issues – and the choice is obvious. But for consumers, it’s not always easy to find information about some more challenging options.
So, our guide below is a first attempt at some of the questions and issues raised about pots and pans, food packaging and plastics, water bottles, cutting boards, and more. Check back for updates and let us know if you have more information. For more on healthier products in the home, see our suggestions for Protecting Your Home and Family.
Aluminum is widely used for cookware, and is a relatively safe material. Concerns have been raised for many years about exposure to aluminum and links to Alzheimer’s Disease: a recent study showed that aluminum in drinking water could lead to a greater risk of Alzheimer’s. But organizations working on preventing the disease, like the UK Alzheimer’s Society, say that a relationship between aluminum exposure and the disease has not been demonstrated. Aluminum is prevalent in the environment and leaching from aluminum cookware is thought to add insignificant amounts. Some avoid aluminum as it can discolor foods; egg whites or buttercream icings whipped in aluminum bowls may turn grey. Highly acidic foods (like lemon juice) or highly basic ingredients (baking soda) are more likely to react with aluminum, so those who choose aluminum may want to avoid aluminum for these uses.
Anodized aluminum is made by placing the material in an acid solution and exposing it to an electric current, creating a layer of aluminum oxide on the surface. Anodizing aluminum can eliminate leaching, but some anodized pans contain the hazardous chemicals PFOA or PFTE (see Teflon, below) in their surface coatings, so check with manufacturers if you are interested in anodized cookware.
Aluminum foil is not likely to leach significant amounts of aluminum into food as a wrap; however, when cooking (for example, steaming wrapped fish), an easy precaution is to wrap the food first in waxed or parchment paper, and then foil, so the foil is not in contact with the food.
Life-cycle issues: aluminum is a product of bauxite mining, which has been linked to health problems for miners and surrounding communities, including hypertension and asthma/respiratory illness. Bauxite mining is often in tropical areas that include sensitive rainforest ecosystems, and a comparison of aluminum beer cans versus bottles found that aluminum required twice as much energy inputs as glass for virgin products (ie, without recycled content). Aluminum-maker Alcoa claims that aluminum cookware (and many other aluminum items) can be recycled, but if your local curbside recycling doesn’t accept cookware (many do not), you will need to find a commercial recycler. Otherwise, for disposal of unwanted aluminum, check with local scrap metal dealers to see if they accept cookware.
In a 1997 study, the Environmental Working Group tested food from 97 canned products and found bisphenol-A (BPA) in over half of the samples, including high levels of the chemical in infant formula, soups, and pasta. BPA is an estrogen mimicking chemical that has been linked to heart disease, diabetes, and effects on the brain, behavior and prostate gland in fetuses, infants and children (see plastics, below). BPA can leach from the plastic lining used in most canned foods and contaminate the food. In Japan, some manufacturers have replaced BPA with an ethylene lining, but only a few U.S. food makers have followed suit. The organic company Eden Foods, for example, has eliminated BPA from its canned foods.
Cast iron has long been favored as a safe, sturdy material for cookware. Cast iron can add significant amounts of dietary iron to food, especially to acidic foods, which can be nutritionally beneficial. Proper seasoning and care is important to avoid rusting and maintaining the pans. Cast iron pans are known to be long-lasting and have been kept in families for generations.
Enamel-coated cast iron pans are also popular (enameled steel pans are also available). The enamel coating is usually silica-based (see silicone, below); in older cookware and some cookware from outside the U.S., glazes and decorative items (especially bright reds, yellows and oranges) may contain lead and/or cadmium, which are highly toxic when ingested. Some new cookware boasts a ceramic “nano-coating” as a safer non-stick surface, but there has been little evidence of safety of these nanomaterials.
Life cycle: As with all mined metals, iron mining can be a polluting industry; workers may be exposed to excessive concentrations of iron oxide, increasing the risk of lung cancer. Iron is recyclable and some cookware may be made with some recycled content.
Most ceramics and terra cotta pots and cookware are safe and useful for storage; like glass, ceramics can be used for baking or cooking, but are senstive to rapid heat changes and may crack or shatter. Due to the potential for lead leaching, storing acidic foods in ceramics for long periods should be avoided (see below).
In 1971, FDA established a legal standard on cadmium and lead leaching from ceramics, and has since proposed tighter guidelines, which today serve as a voluntary industry standard. Under FDA guidelines, lead leaching is banned at more than 0.5 to 3 parts per million (ppm), depending on the type of ceramic (eg, ceramic mugs and cups must meet the 0.5 ppm standard, plates and flatware must be less than 3 ppm). In California, consumer protection law limits lead in any foodware surface to no more than 0.1 ppm.
Despite the FDA guidelines, state and local authorities have found problems and issued health warnings about lead risks from certain imported pots. Terra cotta pots from Mexico and Latin America, and some Asian dishware have been identified as lead hazards. The CDC in 2003 also reported finding high lead levels in a variety of imported French ceramic dinnerware after a child whose family used the product was found to have an elevated blood lead level.
A life-cycle comparison of ceramic cups versus paper or styrofoam favored ceramic, over the long-term, primarily due to their long usefulness over single-use containers. A similar comparison with stainless steel or styrofoam also favored ceramic.
Copper is prized among serious cooks for its ability to conduct and distribute heat quickly and evenly. Copper toxicity can be a health concern with acute exposures, so almost all copper pots and pans sold today are lined with steel or tin (people with nickel allergies should look for tin-lined copper, see stainless stell, below). Unlined copper bowls are sometimes still used, primarily for baking (a chemical reaction with whipped egg whites creates a strong bond, so unlined copper is favored for making meringues), but this is not believed to present a significant exposure hazard, as long as acidic foods are not used.
Life cycle: Copper mining has been associated with worker and community health hazards, as well as habitat destruction and pollution. Scrap metal dealers may accept copper pans for disposal.
Glass is used primarily for storage and mixing bowls, and for some baking pans. Glass is sensitive to rapid temperature change, and can crack when heated or cooled too quickly. Glass pots and pans are thus less widely used. It is otherwise non-reactive and safe to use for storage and other purposes. Glass is highly recyclable, although not all glass cookware can be included in community recycling programs, and may need to be brought to commercial recyclers. As crystalware, glass can contain lead, especially older pieces.
Life-cycle: Glass is primarily from mined silica (see silicon, below). Glass manufacturing can create harmful emissions and discharge issues. Glass recycling is widespread, but not all municiple recyclers accept cookware in mixed glass recycling programs, and may need to go to commercial recyclers.
Plastics are non-renewable, petroleum-based products that contain various chemical additives depending on the type of plastic and the desired properties of the final product. From a life-cycle perspective, plastics are less favored, since there are environmental and health hazards in their production, use and/or disposal. Polyvinyl chloride (PVC) is known as a “poison plastic” due to the toxic impacts throughout its life cycle, and should be avoided whenever possible. Some phthalates, a class of chemicals used to soften PVC and other plastics, are known to cause reproductive harm and have been banned in Europe and regulated in some states. Scientists have raised concerns about BPA, used in polycarbonate plastic (in canned food liners and water bottles, among other uses), and possible effects on the brain, behavior and prostate gland in fetuses, infants and children at current human exposures. A recent Journal of the American Medical Association study (quoted in an article from the Columbia Missourian) showed that people with the highest levels of BPA in their urine “were more than twice as likely to report having cardiovascular (heart) disease or diabetes.”
In Europe, BPA has been banned in products for children under 3 since 2006; in the U.S, the city of San Francisco followed suit in 2007, but federal regulators have lagged behind. Due to the market influence, most baby bottle makers have reformulated their plastic bottles; consumers should look for “BPA-free” bottles and choose products made with polypropylene, polyethylene or tempered glass, or disposable bottle systems with pre-sterilized polyethylene drop-in bags.
Several useful guides to the use of plastics in food service are available; the Institute for Agriculture and Trade Policy’s guide is an excellent resource, along with the guide’s “Q&A” resource. In summary, IATP lists plastics by the numbered symbol seen on most plastic containers. For food use, they advise avoiding the use of PVC (#3 plastics), polystyrene (Styrofoam, #6 plastics), and polycarbonate (#7PC plastics – not all #7 plastics are polycarbonate, so look for “PC” or check with producers if you are unsure). Polyethylene and high density polyethylene plastics (numbered 1 or 2) are safer choices and are the most recyclable plastics (see more on plastic recycling, below).
In general, plastics should not be heated, as heating can leach out toxic chemicals. For example, a recent study found that heating can result in rapid leaching of BPA from plastic bottles. Plastics marked “microwave safe” are not generally tested for leaching, but merely for durability, so this label is not a guarantee of safety. Fatty and acidic foods can also break down plastics, and should not be stored for long periods. Detergents can break down plastics, and wear and tear can lead to cracking and possibly more leaching. Older plastics should be discarded.
Most plastic wraps are not made from PVC, but consumers should look for non-PVC labels to be sure. Most wraps also are no longer made with phthalates, although the chemical softeners used to replace phthalates (usually from a class of chemicals called adipates) have not been well-studied for their health effects.
Life cycle: Plastics pose environmental threats during production and disposal. Plastic recycling is often limited and nearly 95% of plastic goes unclaimed. Unlike glass, recycled plastic also rarely makes its way back to its original purpose, so recycled plastic bottles are made into other products, such as plastic benches or outerwear, that are then discarded at the end of their useful lives.
In June 2009, Indonesian health authorities warned that some melamine plastic dishware can leach formaldehyde and pose a health threat. Melamine has been implicated as a health issue in food, and also previously in dishware, but the safety issues in food versus plastics do not appear to be directly related.
Melamine is a chemical used in the making of pesticides, fertilizers, and plastics, some of which are used as plastic dishware. Melamine made headlines in 2007 when it was found that hundreds of pet foods made with some wheat or rice ingredients from China were contaminated with the chemical, leading to illnesses and deaths of hundreds of cats and dogs across the country. Adding melamine, which is rich in nitrogen, to food ingredients can create a false spike in tests of the food’s protein content, since protein tests are usually derived by measuring nitrogen content. Melamine in food raised even more concerns in 2008, when more than 50,000 infants in China fell ill (with at least 4 deaths) from melamine contamination of milk-based infant formulas.
But food contamination from melamine occurs when the chemical reacts with another chemical, cyanuric acid, that is believed to have also been added to food ingredients in attempts to alter their apparent nutritional profile. Melamine plastics have not been implicated in any similar contamination.
There have for several years, however, been reports of formaldehyde, used in making melamine plastics, leaching from some melamine dishware. Formaldehyde is a known carcinogen, and studies have shown it can leach from plastic, especially when used with hot or acidic foods. A 2005 study, for example, found that five of fifty melamine plastic products tested leached levels of formaldehyde that violated UK safety standards. Researchers suggested that cracked, pitted and/or discolored pieces were most suspect.
Bottom line: consumers should look for safer choices and avoid melamine plastic dishware; if it is not feasible to dispose of your melamine dishware, avoid using older, cracked pieces and do not use the dishware for hot or acidic foods.
Gaining in popularity are plastics that are based not on petroleum but on renewable plant materials. Bio-plastic plates, cutlery, and other products are sometimes advertised as renewable, recyclable and/or compostable products, and have been welcomed as environmentally preferable substitutes for traditional plastic.
But bio-plastics are far from a perfect solution:
- They may not always be as recyclable or compostable as advertised. Bio-plastics often can only be properly composted in large, commercial composting operations, yet consumers do not always know this or have easy access to such facilities.
- They may not be easily recycled. Recyclers often cannot mix bio-plastics with other plastics, making them unwanted in most plastic recycling streams.
- Using food crops and arable land to produce plastics is difficult to justify, especially given the increasing demands of a growing world population.
- Bio-plastics made from crops grown on mass factory farms carry all of the environmental issues associated with our destructive industrial agriculture system. Few if any bio-plastics are made with source material from sustainable farms. Since much American corn is genetically modified (GMO), corn-based bio-plastics (polylactic acid or PLA, used in Natureworks products, one of the most widely sold bioplastics) are made with some GMO corn (this is not a concern with wheat, sugarcane, or other bio-plastics).
- Chemical additives used in creating bioplastics may contain chemicals of concern, but bioplastic developers may not fully disclose ingredients used in their production, so this can be difficult to evaluate.
Still, when plastics are unavoidable, many consumers and institutions are looking for bio-plastic alternatives. A coalition of environmental and health organizations have developed draft guidelines for sustainable bioplastics production, to provide buyers with a tool by which they can compare the life-cycle costs and benefits of bioplastic options.
Silicone is a synthetic rubber which contains bonded silicon (a natural element which is very abundant in sand and rock) and oxygen. Silicone cookware is gaining popularity as it creates a non-reactive, heat stable nonstick surface for baking sheets, linings for baking pans, pots and pans, spatulas, and other uses. There is little information on any additives used to make silicone, but it appears to be a safe material.
Life cycle: like glass, silicone primarily comes from mined silica (sand). Silica mining, while not benign, is generally considered less environmentally destructive than mining of most metals. Workers in mining and manufacturing can suffer from silicosis, an incurable lung disease that kills thousands of people each year.
Stainless steel is a blend of materials including steel, chromium and (usually) nickel. Stainless steel is widely used, is generally non-reactive, durable, and safe. There is some stainless steel cookware made without nickel, which is considered lower quality but is important for those with nickel allergies. The percent of each material is sometimes given: 18/10 stainless is 18% chromium and 10% nickel. Those with nickel allergies should look for stainless marked 18/0.
Life cycle: Mining iron for steel is often environmentally destructive, and can cause serious, long-term pollution to surface water and groundwater. ”Tailings,” leftover materials from mining, can include toxic heavy metals and other toxins such as cyanide or sulfuric acid. Steel production can release air emissions of toxins including benzene, ammonia and toluene. However, stainless steel can be a better life-cycle choice than plastics (see water bottles, below).
Teflon, made primarily by DuPont, has come under fire for two chemicals linked to potential health hazards. Polytetrafluoroethylene (PTFE) and/or perfluorooctanoic acid (PFOA) are found in Teflon, and have been linked to hazardous fumes (including some resulting in fatal exposures to small bird house pets), and in animal studies have caused cancer and birth defects. DuPont says that only extremely high temperatures can create a hazard with Teflon pans, and a Consumer Reports study looking at using Teflon at 400 degrees found no hazardous fumes. But the Environmental Working Group found that Teflon pans can quickly reach temperatures above 500 degrees, noting that toxic particles are relased at 464 degrees.
Plastic, aluminum and stainless steel water bottles are widely available. In plastic bottles, consumers should avoid polycarbonate (#7 PC plastics), as these can leach BPA. Leaching of BPA from other plastic water bottles is rare but possible: an NRDC study of more than 1,000 non-polycarbonate water bottles found one that did leach BPA into water. Some makers of plastic bottles, like Nalgene and Camlback, have eliminated BPA from their products.
Aluminum bottles are favoired by some, but these often are plastic-lined, and the linings can contain BPA. Some SIGG aluminum bottles use BPA, although the company says that studies show no leaching into water, while other “generic” lined-aluminum bottles did leach.
Stainless steel bottles may be lined or unlined; consumers concerned about BPA should look for unlined stainless steel. Good Housekeeping recently reviewed 32 water bottles advertised as BPA-free, including several made from unlined stainless steel. A New York Times report on one life-cycle analysis found steel water bottles highly preferable to plastic.
Wooden spoons, bowls, and cutting boards are widely used, safe, and are re-gaining popularity. There has been controversy over wood versus plastic for cutting boards, since it was believed that bacteria could fester in cuts in softer wooden boards, while harder plastics would be safer. However, research by the University of California found that wooden boards are as safe if not safer than plastic boards, and were easier to disinfect. All cutting boards should be wshed thoroughly after use; a disinfectant spray of vinegar followed by a spray of hydrogen peroxide can also be used to kill bacteria on wood, plastic and metal. To avoid cross-contamination, cooks should keep at least two sets of cutting boards: one for meat and poultry, and one for everything else (due to the prevalence of salmonella in poultry, some even suggest a separate board just for poultry).
At least one company, Bambu, makes a line of cooking utensils, bowls, and other bamboo kitchen products with wood sourced from organic, fair trade bamboo plantations.