large amount of crushed plastic beverage bottles

Phthalates

General

Phthalates are esters of phthalic acid and are commonly used as plasticizers to enhance the flexibility, durability, and longevity of plastics and other materials. They are widely used in products such as polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyethylene (PE), polypropylene (PP) plastics, cosmetics, personal care products, and medical devices. The most used phthalate esters (PAEs) are di-(2-ehtylhexyl) phthalate (DEHP) followed by dibutyl-phthalate (DBP), dimethyl phthalate (DMP), di-n-octyl phthalate (DOP), diisononyl phthalate (DiNP), and diisodecyl phthalate (DiDP). While they are not intentionally added to food products, they can contaminate food along the supply chain from preparation, processing equipment, packaging and storage. DEHP is the phthalates with the highest incidence and often the highest concentration in various food products such as fruits and vegetables, cereal and cereal products, milk and dairy products, fish, meat, snacks, fats and oils (Krithivasan et al., 2023), sauces and condiments.  

Because phthalates are not chemically bound to the products in which they are used, they are prone to leaching into the environment, including food products. They can contaminate foods by the following ways:

  • Environmental Contamination: Foods can be contaminated by phthalates from the environment through water, air, and soil where food ingredients are grown or processed. 
  • Contamination during Processing: Food processing equipment and materials such as tubing, conveyor belts, and food handling gloves may contain phthalates that can migrate into foods. 
  • Migration from Packaging: Phthalates can leach from plastic food packaging, especially under warm conditions and/or for an extended period (Jayaweera et al., 2020).  

Research indicates high phthalate exposure has been associated with inflammation, oxidation stress, and chronic conditions such as diabetes, obesity, and cardiovascular diseases (Attina et al., 2015; Su et al., 2019). DEHP, DiDP, DiNP, and phthalic acid exposures have been found to be associated with decreases in gestational age and increased preterm birth risk (Trasande, et al. 2024). Phthalates have been shown to interfere with hormonal functions, impacting reproductive health and development (Hauser & Calafat, 2005).

The toxicity and risk assessment of phthalates are usually expressed through estimated daily intake (EDI) values and compared with tolerable daily intake (TDI) levels established by health agencies. The European Food Safety Authority (EFSA, 2019) has set a TDI of 0.05 mg/kg and 0.15 mg/kg body weight/day for DEHP, and DiDP/DiNP, respectively. In other words, for a 150-pound consumer, TDI is 3.4 mg for DEHP and 10.2 mg for DiDP/DiNP per day. California Proposition 65 established No Significant Risk Levels (NSRLs) and Maximum Allowable Dose Levels (MADLs) for some phthalates.

Accurate measurement of phthalates in foods is critical to assess exposure properly. Gas Chromatography-Mass Spectrometry (GC-MS) is commonly used for all edible oil, including crude, refined and virgin (ISO method). Labs that perform phthalates analysis should have their accuracy validated by inter-laboratory comparisons and adhere to international standards like those established by the International Organization for Standardization (ISO).

Guidance for Industry

Food processors play a crucial role in minimizing phthalate contamination. Reducing exposure requires a holistic approach incorporating material selection, handling practices, processing methods, and quality control. Some key sources for processors to consider are:

  • Environmental Contaminants: Phthalates present in the processing environment (e.g., air, dust) can also lead to contamination.
  • Processing Equipment: Contact with phthalate-containing equipment (e.g., hoses, seals, conveyor belts) can contaminate edible products.
  • Packaging Materials: Phthalates can migrate from plasticizers found in packaging materials, such as PVC, into food products. 
  • Transport and Storage: Phthalates can leach into products from plastic containers and liners used during transport and storage.

Knowing the common sources of phthalates, processors and packers and utilize the following strategies to reduce phthalates:

  1. Use phthalate-free materials: 
    1. Packaging: Shift to phthalate-free plastic packaging alternatives and glass.
    2. Processing Equipment: Replace food contact surfaces and phthalate-containing components, including plasticized tubing and holding tanks with phthalate-free or stainless-steel parts in processing facilities throughout the supply chain. 
    3. Transportation: Use transport containers and liners certified as phthalate-free. Consider alternative packaging and transport solutions, such as bulk shipments in non-reactive metal containers.
  2. Process adjustments:
    1. Leach and migrating of phthalate can be facilitated by high temperature, on the other hand, some phthalates may be removed via high temperature distillation (Krithivasan et al., 2023). 
    2. Design packaging that significantly limits fat content contact with packaging materials, as phthalates tend to bind to fats.
    3. Separate high-risk phases of manufacturing from lower-risk ones to further diminish contamination chances.
  3. Implement Good Manufacturing Practices (GMPs):
    1. Avoid using phthalate-containing cleaning products and ensure proper sanitation of pressing equipment to eliminate soil and residue containing phthalates. 
    2. Improve handling protocols to reduce the risk of phthalate contact with foods, for instance by using dedicated, contamination-free areas for sensitive processes.
    3. Regularly audit supply chains to ensure that raw materials and ingredients are free from phthalate contamination.
  4. Adopt Efficient Quality Control Measures:
    1. Regular Testing: Conduct regular and comprehensive testing of food and oil products for phthalate levels using official methods.
    2. Limit Periodic Audits: Perform periodic internal and external audits to ensure compliance with safety standards and to identify contamination sources.
  5. Environmental Controls:
    1. Improve filtration systems in manufacturing areas to limit phthalate contamination from soil and water. 
    2. Implement strict cleaning protocols to minimize phthalate residues on surfaces and equipment.
  6. Traceability and Transparency:
    1. Maintain detailed records tracing back to the sourcing of materials, processes, and storage conditions. 
    2. Publish transparency reports relevant to phthalate measures to enhance consumer trust and meet regulatory requirements.

Information for Consumers to Reduce Exposure

Phthalates are present in indoor dust and air and everyday products; therefore, it is not possible to avoid phthalates 100%. It's important to strike a balance between being aware and taking practical steps to reduce exposure without inducing fear or drastically limiting food choices. The long-term health risks associated with phthalate exposure are generally related to consistent, high-level exposure rather than occasional exposure through normal dietary habits.

Phthalates can migrate from plastic packaging, food processing equipment, and food contact materials into foods, especially fatty foods like oils, dairy products, and meat. Focus on fresh foods and consuming less processed and packaged foods may help to reduce exposure.

Consumers can avoid using certain plastics marked with recycling codes 3 (PVC) and certain flexible plastics marked 7 (mixed materials, potentially including phthalates). If possible, opt for food products packaged in glass, stainless steel, or phthalate-free plastics. Avoid heating food directly in the plastic packages or in contact with cooking utensils that contain phthalate and use microwave-safe glass or ceramic containers instead.

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