The brightly colored sticker found on produce represents a significant point of confusion for consumers managing waste responsibly. As more households participate in food scrap collection or backyard composting, the fate of these tiny labels becomes a frequent question. Produce stickers are designed for durability throughout the supply chain, which conflicts with biological breakdown. Understanding their composition and how composting works provides the clearest answer to this environmental dilemma.
Composition of Standard Produce Labels
The vast majority of standard produce labels are manufactured for performance rather than compostability. The main body of the sticker, known as the face material or substrate, is typically a thin plastic film. Common materials include vinyl or biaxially oriented polypropylene (BOPP), which are oil-based polymers. These plastic films are chosen because they are flexible, resistant to moisture, and withstand handling and washing without degrading. This durability prevents them from decomposing naturally. When these plastic-based stickers enter an organic waste stream, they do not biodegrade; instead, they fragment into microplastic pieces that contaminate the finished compost.
Non-Degradable Components: Adhesives and Inks
Even if a sticker’s face material were made from paper or a bioplastic, the adhesive and inks often prevent full compostability. The adhesive layer, typically an acrylic-based formulation, keeps the sticker attached through transport and handling. While food-safe, these glues are not designed to break down biologically and are a significant source of contamination in composting facilities. Similarly, the inks used to print the Price Look-Up (PLU) code and branding resist smudging and fading. These inks frequently contain petroleum-based polymers or inorganic pigments, such as metal-based compounds, for stability and vibrant color. For a material to be certified as compostable, the entire system—substrate, adhesive, and inks—must meet stringent standards for disintegration and biodegradation. Standard adhesives and inks ensure the sticker will not fully decompose.
Home Composting Versus Commercial Facilities
The environment in which material is composted defines whether specialized labels will break down. Home composting piles operate at relatively low and inconsistent temperatures. Backyard bins rarely maintain the sustained heat necessary to degrade tougher materials like certified bioplastics. Home environments generally remain below the 131°F (55°C) threshold required for industrial-grade compostable items to properly break down. If a standard sticker is placed in a home compost pile, it will persist indefinitely as a plastic contaminant. Commercial or industrial composting facilities are engineered to operate under standardized, high-heat conditions. These facilities carefully control moisture, oxygen flow, and temperature, typically maintaining 130°F to 170°F (55°C to 77°C) for sustained periods. This controlled, thermophilic environment allows them to process materials certified to meet industrial standards, requiring breakdown within 90 to 180 days. While these facilities can process certified labels, they reject standard plastic stickers because the fragments contaminate the finished compost.
Identifying Certified Compostable Labels
Consumers seeking to compost produce stickers should look for specific third-party certification marks. These certifications ensure the entire label system—substrate, adhesive, and ink—meets verifiable standards for biodegradation. In North America, the Biodegradable Products Institute (BPI) certification, adhering to ASTM standards, is the recognized mark for commercial composting facilities. European standards often reference EN 13432, represented by the TÜV Austria “OK Compost INDUSTRIAL” logo. For backyard composting, the standard is stricter due to lower temperatures. Labels that break down in a home setting carry the “OK Compost HOME” certification, confirming the material fully decomposes in less controlled, ambient conditions.