Bisphenol A, or BPA, is an industrial chemical that has been used since the 1960s to make certain types of plastics and resins. Its use in food packaging is primarily to harden plastics and to create protective internal epoxy resin coatings for metal cans. This chemical can leach from these materials into the food and beverages they contain, and while the amounts are often very low, concerns have prompted many to seek out BPA-free options.
Canned Foods and Beverages
The most significant source of BPA exposure from food is the protective internal epoxy resin coatings of metal cans. These resins are used to prevent the metal from corroding and to extend the shelf life of the food. Heat and storage time are critical factors that influence the degree to which BPA can migrate from these linings into the food.
High-BPA Canned Products
- Canned tomatoes and acidic foods: The acidity of foods like tomatoes, citrus, and certain sauces can accelerate the leaching of BPA from the can lining into the product.
- Canned fish and meat: Studies have found BPA contamination in canned fish and meat products, with some research indicating it's a notable source of dietary exposure.
- Canned coconut milk: Research has specifically shown high levels of BPA in some canned coconut milk products.
- Infant formula: Historically, BPA was used in the linings of some infant formula cans. Following bans, many manufacturers have shifted to alternatives.
Plastic Food and Drink Containers
BPA is a key component in polycarbonate plastic, which is a rigid, clear plastic used for a variety of consumer goods that come into contact with food and drinks. Exposure from these products is also possible through leaching.
Common Polycarbonate Sources
- Reusable plastic water bottles: Many older or unlabelled reusable water bottles are made from polycarbonate plastic, which can release BPA, especially when exposed to heat or harsh detergents.
- Food storage containers: Some hard, clear plastic food storage containers and tableware are made with polycarbonate and can be a source of BPA contamination, particularly when used for heating food in a microwave.
- Large water cooler jugs: The large, 5-gallon water cooler jugs are frequently made from polycarbonate plastic.
- Plastic lids and sealants: BPA-containing epoxy resins can also be used in the lids of glass jars and on bottle caps, where they contact the food or beverage.
How to Identify Potentially BPA-Containing Plastics
To determine if a plastic container might contain BPA, you can check the recycling code, though this method is not foolproof.
- Recycling Code 7 (“Other”): This is the most common code for plastics that may contain BPA, as it is a catchall category for plastics not fitting into codes 1-6. However, it also includes many BPA-free plastics like Tritan and PLA.
- Look for “BPA-Free” labels: The most reliable way to identify safer plastics is to look for explicit labeling.
- Choose alternatives: Opting for glass or stainless steel containers is the most effective way to avoid plastic-related BPA exposure.
How Leaching Happens
The migration of BPA from packaging into food is not constant and is influenced by several factors:
- Heat: Heating plastic containers in the microwave or washing them in a dishwasher can cause the plastic to break down over time, increasing the rate of BPA leaching.
- Storage time: Longer storage periods, especially for canned goods, increase the contact time between the food and the packaging, potentially allowing for more BPA to leach into the contents.
- Acidity: As mentioned, acidic foods can increase the leaching of BPA from can linings.
- Wear and tear: Scratched or worn plastic containers may leach more chemicals than new ones.
Comparison of BPA-Containing vs. BPA-Free Options
This table highlights the differences between common food packaging materials regarding BPA content and potential risks.
| Feature | BPA-Containing Packaging (e.g., Polycarbonate) | BPA-Free Alternative (e.g., Glass, Stainless Steel) |
|---|---|---|
| Material | Polycarbonate plastic, epoxy resin coatings | Glass, stainless steel, some labeled plastics (Tritan, HDPE) |
| BPA Content | Contains Bisphenol A, which can leach into food | Free of Bisphenol A |
| Microwave Safe | Not recommended; heating increases leaching | Generally safe; will not leach chemicals into food |
| Dishwasher Safe | Potential for wear and tear, increasing leaching | Safe to wash; maintains integrity without leaching |
| Risk of Exposure | Higher, especially with heat or acidic contents | None related to BPA leaching |
| Durability | Shatter-resistant, but can degrade with heat and wear | Highly durable (stainless steel), or brittle but chemically inert (glass) |
Mitigating Your Exposure
To effectively reduce your intake of BPA from food, consider these actionable steps:
- Prioritize fresh or frozen foods: Whenever possible, opt for fresh fruits, vegetables, and meats. Frozen versions are also excellent as they typically do not require BPA-lined packaging.
- Choose glass containers: Store food and beverages in glass jars, bottles, or containers. This is especially important for hot foods and liquids.
- Seek out BPA-free cans and packaging: Many manufacturers now clearly label their products as BPA-free, particularly for canned goods. Look for these labels in the store.
- Use alternatives for infants: For infants, who are particularly vulnerable, use glass baby bottles or ones explicitly certified as BPA-free.
- Avoid microwaving plastics: Never heat food in a plastic container, especially if it is not labeled as microwave-safe and BPA-free. Use glass or ceramic instead.
Conclusion
Bisphenol A, or BPA, is an endocrine-disrupting chemical that primarily enters the human body through dietary sources, specifically from the epoxy resin linings of metal cans and polycarbonate plastics. While regulatory actions have reduced its use in some products, particularly those for infants, it remains present in some food packaging. By understanding where BPA is found in food and adopting simple alternatives like choosing fresh foods, using glass or stainless steel containers, and avoiding heating food in plastic, consumers can significantly minimize their exposure. The trend towards transparent, BPA-free labeling is making it easier for individuals to make informed choices for their health. For more information on understanding food contact materials, see the FDA's official page on BPA.
Where to Learn More
For a deeper dive into the chemical properties and regulatory landscape of bisphenols, resources from environmental health and food safety organizations are invaluable. The European Environment Agency, for instance, provides comprehensive reports on human exposure and health impacts. Awareness and informed consumer choices are key to mitigating potential risks associated with this ubiquitous chemical.
