More than 1,800 food contact chemicals (FCCs) are known to migrate from food processing equipment and storage and packaging containers, and many of these have hazard properties of concern — and others are still being tested for toxicity, according to a 2024 review article titled “Evidence for widespread human exposure to food contact chemicals” from the Journal of Exposure Science & Environmental Epidemiology. 

Phthalates (the “everywhere chemical”) constitute a group of chemicals found in plastics and plasticizers, and FDA has been slowly changing its rules and doing additional research to determine various action plans it can take regarding FCCs. Consumer groups have been asking whether FDA has been doing enough to reduce chemical toxicities in food and beverage products.

On Oct. 29, 2024, the FDA updated its “Phthalates in Food Packaging and Food Contact Applications,” which affirmed its 2022 Final Rule to remove 25 plasticizers in various food contact applications — all 25 had already been abandoned by industry. The FDA currently allows nine phthalates (eight for use as plasticizers and one for use as a monomer) in the production of food contact polymers. Phthalates (aka ortho-phthalates) are chemicals used in plastic products, for example, to soften PVC — to make it less brittle — e.g., flexible plastic tubing. [1]

While phthalates are not authorized as food additives, they have been shown to migrate to food and beverages from even non-PVC food contact materials, according to an article from the Food Packaging Forum. Phthalate-based catalysts are also used in the production of polypropylene plastics. A UK study found phthalates in food packaging materials, for example, a paper/foil/plastic laminate beverage carton, a foil-lined pouch and several plastic bags in carton boxes. Exposure to phthalates can be a health concern because these substances have been linked to reduced fertility and reproductive toxicity in animal studies. In humans, phthalates have been associated with adverse health effects such as obesity and reduced masculinization in newborn boys. For certain phthalates (DEHP, DBP and DIBP), food is thought to be the main exposure source. [2]

Prior FDA Activities

On April 16, 2016, the FDA received a citizen petition by several public interest groups that requested a ban on the food contact use for certain phthalates and revocation of the prior sanctioned authorization of other phthalates based on alleged safety concerns. On May 19, 2022, the FDA denied this citizen petition because the petition did not demonstrate through scientific data or information that these actions were warranted.

After another citizen petition filed on May 20, 2016 requesting the grouping of 28 phthalates into a single class failed approval by FDA, it was noted that 23 of the 28 had already been discontinued by industry and were revoked in the FDA final rule. In addition to the 23 discontinued phthalates, FDA dropped two other substances used as plasticizers, adhesives, defoaming agents, surface lubricants, resins and slimicides. Therefore, on May 19, 2022, the FDA responded to this petition by issuing a final rule to amend its food additive regulations to revoke the authorizations for the food contact use of these 25 substances.

Over the last few years, FDA has analyzed numerous samples of PVC and non-PVC fast food packaging and food contact articles (for example, gaskets, tubing and conveyer belts) available on the U.S. market for the presence of phthalates. According to FDA, data from these studies were published in 2018, 2021, and 2022 — and suggest that manufacturers have been replacing phthalates as their primary plasticizer with alternative compounds. For example, no phthalates were detected in representative samples of food contact tubing used by industry that were obtained and analyzed in 2021. That evidence suggests, says FDA, that in 2021 the use of phthalates in food contact applications is limited and consumer exposure to phthalates from food contact uses is decreasing.

Phthalates in Food Packaging

In the past, certain phthalates have been used in food packaging or other food contact applications such as components of adhesives, lubricants and sealants, but have largely been discontinued and replaced with other substances. Recent studies, however, have found phthalates in many types of food — from fast food to fresh fruits and vegetables. According to the Environmental Defense Fund, the chemicals find their way into food mainly through packaging and food handling equipment — such as gloves, cellophane, paper and paperboard and plastic —in contact with food. [3]

A 2013 study based on convenience samples of commonly consumed foods in Albany, New York, found nine phthalates in 72 individual food samples, ranging from beverages in plastic bottles or jugs, milk in plastic, fish with foam trays and plastic wrap, fruits and vegetables in plastic, ground beef in plastic, pork and beef products in plastic, vegetable oils in plastic, infant foods and others. The range of detection frequency of individual phthalates varied from 6% for dicyclohexyl phthalate (DCHP) to 74% for di-2-ethylhexyl phthalate (DEHP). DEHP concentrations were the highest of the phthalates measured in all foods except beef (where di-n-octyl phthalate (DnOP) was the highest phthalate found], with pork having the highest estimated mean concentration of any food group (mean 300 ng/g; maximum, 1,158 ng/g). Estimated mean adult intakes ranged from 0.004 μg/kg/day for dimethyl phthalate (DMP) to 0.673 μg/kg/day for DEHP. [4]

The Albany study concluded that phthalates are widely present in U.S. foods. While estimated intakes for individual phthalates in this study were more than an order of magnitude lower than U.S. Environmental Protection Agency reference doses, cumulative exposure to phthalates is of concern, and a more representative survey of U.S. foods is indicated. The study noted that the U.S. EPA identifies eight phthalates in which it is monitoring, and include DBP, DiBP, BBzP, DnHP, DEHP, DnOP, DINP and DIDP. 

In humans, phthalates are quickly metabolized, and the metabolites rather than the parent compounds are used as biomarkers of exposure. Phthalate metabolites have half-lives in humans under 24 hours, and therefore represent short-term, recent exposure to phthalates. [5]

One way to recognize products that contain phthalates is to look for the numbers inside the universal recycling symbols on the bottom of plastic bottles. According to Pennsylvania State University, plastics with #3, #6, or #7 recycling codes should be avoided, whenever possible. Research has also found that even PET can leach phthalates into food or water due to certain environmental conditions, e.g. pH (acidity) or environmental temperature. Image: Wayne Labs

Unending Exposure

While the 2013 Albany study notes that phthalates are eliminated from the human body in a day or two, the problem is the ongoing, never-ending exposure to phthalates. The National Academies of Science recognized the importance of cumulative exposure — generally and specifically — to phthalates when it released the report, Phthalates and Cumulative Risk Assessment—The Tasks Ahead, in 2008.

Yet today, in spite of efforts made by packaging suppliers and food processors, phthalates in food and beverage products remain “at high levels” as a January 2024 study conducted by Consumer Reports (CR) found that some of the worst offenders are certain canned foods (e.g., Annie’s Organic Cheesy Ravioli with a level of 53,579 nanograms (ng) per serving and Wendy’s Crispy Chicken Nuggets (paperboard) at 33,980 ng per serving. [6] 

The CR study also checked for bisphenols (BPA) but did not publish the results in the article — however, BPA numbers have generally improved since 2009, the last time CR tested for BPA. FE has published several articles in the past on BPA, which when doing a search on the FE website, yielded 62 results. 

According to CR, supermarket and fast-food chains, as well as food manufacturers, should be required to act to reduce BPA and phthalates in our food supply. This means setting specific goals for reducing these contaminants from all food processing and packaging equipment throughout their supply chains.

PET as a Phthalate Source?

Generally speaking, PET has not been thought to be a source for phthalates. Rather, PVC and polystyrene plastics have been considered major sources of phthalates exposure. A recent study showed that even PET can be a source of phthalates under the right conditions. While PET (polyethylene terephthalate) intrinsically contains no phthalates — despite its chemical name —it has been and still is a great packaging choice under normal environmental conditions.  

However, a 2022 study published in Molecules, found the potential for PET packaging, when exposed to changes in environmental conditions such as pH, temperature and irradiation can improve contaminant migration from PET food packaging to food and beverages. In particular, the study looked at the in-vitro effects of p-phthalates terephthalic acid (TPA) and dimethyl terephthalate (DMT) on human cells that are responsible for controlling weight gain, which has been a reported issue for phthalate exposure. [7]

The 2022 research found that PET bottles of mineral water from different manufacturers contained very low concentration of phthalates initially, but after storage of PET bottles for 10 weeks at up to 30°C (about 86°F), phthalate concentrations in the water had increased. The study concludes that data is lacking on the adipogenic (health) effects of p-phthalates, especially at environmentally relevant very low concentrations. Thus, there is a high level of uncertainty regarding their suitability as safe compounds. “Taking into account humans’ close and constant contact with plastics, it seems appropriate that ascertaining safe levels of TPA and DMT exposure is considered a high priority,” says the study’s authors. [8]

What are Acceptable Phthalate Levels?

With plastics and phthalates literally being everywhere, it obviously makes sense that the less humans ingest, the better. So, can reducing phthalates in food from production and packaging make a significant difference?

Determining the acceptable level for BPA and phthalates in food is tricky, says the CR study. Regulators in the U.S. and Europe have set thresholds for only bisphenol A (BPA) and a few phthalates, and none of the foods CR tested had amounts exceeding those limits.

“Many of these thresholds do not reflect the most current scientific knowledge, and may not protect against all the potential health effects,” says Tunde Akinleye, the CR scientist who oversaw CR’s tests. “We don’t feel comfortable saying these levels are okay. They’re not.”

References/Resources:

[1] “Phthalates in Food Packaging and Food Contact Applications,” FDA, 10/29/2024

[2] “Phthalates,” Jane Muncke, Food Packaging Forum, 2012

[3] “Phthalates in food,” Environmental Defense Fund, Feb. 4, 2019

[4] Schecter A, Lorber M, Guo Y, Wu Q, Yun SH, Kannan K, Hommel M, Imran N, Hynan LS, Cheng D, Colacino JA, Birnbaum LS. Phthalate concentrations and dietary exposure from food purchased in New York State. Environ Health Perspect. 2013 Apr;121(4):473-94. doi: 10.1289/ehp.1206367. Epub 2013 Mar 6. PMID: 23461894; PMCID: PMC3620091.

[5] Mitro SD, Chu MT, Dodson RE, Adamkiewicz G, Chie L, Brown FM, James-Todd TM. Phthalate metabolite exposures among immigrants living in the United States: findings from NHANES, 1999-2014. J Expo Sci Environ Epidemiol. 2019 Jan;29(1):71-82. doi: 10.1038/s41370-018-0029-x. Epub 2018 Mar 23. PMID: 29572484; PMCID: PMC6151301.

[6] “The Plastic Chemicals Hiding in Your Food,” Lauren F. Friedman, Consumer Reports, 4 Jan 2024; Updated 8 Feb 2024

[7] Molonia MS, Muscarà C, Speciale A, Salamone FL, Toscano G, Saija A, Cimino F. The p-Phthalates Terephthalic Acid and Dimethyl Terephthalate Used in the Manufacture of PET Induce In Vitro Adipocytes Dysfunction by Altering Adipogenesis and Thermogenesis Mechanisms. Molecules. 2022 Nov 7;27(21):7645. doi: 10.3390/molecules27217645. PMID: 36364480; PMCID: PMC9656719.

[8] Ibid