Common Sprays Used to Treat Produce
In a complex journey from farm to grocery store, fresh produce undergoes several treatments to maintain its quality. These treatments are applied for various reasons, including pest control during growth and post-harvest preservation. When you see a glossy cucumber or a perfectly crisp lettuce, you are likely seeing the result of these processes. The substances used are generally food-safe and regulated, but they are important for consumers to understand.
Protective Waxes and Coatings
One of the most common treatments is the application of an edible wax coating. Many fruits and vegetables, like apples, naturally produce their own waxy layer, called a "bloom," which is often washed off during processing. A new, food-safe wax is then applied to replace it.
- Carnauba Wax: Derived from the leaves of the carnauba palm, this vegetable-based wax is used on many fruits and vegetables to add shine and reduce moisture loss.
- Beeswax: This natural wax is often used for organic produce and is effective at preventing mold and fungus.
- Shellac: Sourced from the lac insect, this natural glaze is a very effective protective coating.
- Paraffin Wax: A common petroleum-based wax used for both conventional and food-grade applications, though not permitted on organic produce.
Antimicrobial Washes and Sanitisers
Beyond waxes, produce is often treated with antimicrobial agents to kill bacteria and prevent cross-contamination. These are typically applied during the washing process at packinghouses or via mister systems in grocery stores.
- Chlorine Dioxide: Used for sanitizing fruits and vegetables, often via immersion baths. It is an effective disinfectant that leaves minimal residue after rinsing.
- Hypochlorous Acid: A widely used antimicrobial agent found in some grocery store misting systems. It helps control pathogens and keep produce fresh.
- Ozone Washing: An environmentally-friendly alternative that uses ozone gas dissolved in water. It effectively kills bacteria without leaving chemical residues.
The Journey from Farm to Shelf
Pre-harvest Treatments
Before produce even leaves the farm, it is subject to a range of sprays to protect it from pests, mold, and rot. These are the agricultural pesticides and fungicides that protect crops and are regulated by government agencies like the Environmental Protection Agency (EPA) in the United States. The World Health Organization (WHO) also sets internationally-accepted maximum residue limits for pesticides.
Post-harvest Treatments
After harvesting, produce is washed to remove dirt, soil, and potential pathogens. It is during this cleaning stage that the sanitizing washes and protective waxes are applied. The purpose is twofold: to ensure food safety and to maintain the visual quality and texture of the produce during transit and display. Waxing, in particular, prevents dehydration and premature decay, which is crucial for nonlocal produce that travels long distances.
In-Store Misting
The signature thunderclap and mist in the produce section is not just for show. Misting systems, often containing filtered and treated water mixed with mild antimicrobial agents like hypochlorous acid, are used to maintain freshness and crispness, especially for leafy greens and herbs. This misting prevents moisture loss without promoting excessive microbial growth.
Comparison of Produce Treatment Methods
| Feature | Edible Waxes | Antimicrobial Washes (e.g., Chlorine Dioxide) | Ozone Washing | Pesticides (Pre-harvest) |
|---|---|---|---|---|
| Purpose | Retain moisture, extend shelf life, enhance appearance | Kill bacteria, prevent cross-contamination | Disinfect without chemical residue | Protect crops from pests and disease |
| Application Stage | Post-harvest processing | Post-harvest processing, in-store misting | Post-harvest processing | During crop growth |
| Residue | Leaves a protective, edible film on surface | Can leave minimal residues, rinsed off | No chemical residue left behind | Residual amounts, regulated by agencies |
| Eco-friendliness | Varies by wax type (plant-based are more eco-friendly) | Can have environmental by-products | Breaks down into oxygen, highly eco-friendly | Varies, can impact environment and soil |
| Consumer Concerns | Appearance, origin of wax (e.g., petroleum-based paraffin) | Chemical exposure, lack of transparency | Safety and effectiveness at proper concentration | Health effects from residues |
Is it necessary to wash produce at home?
Yes, it is crucial to wash all produce at home, regardless of any pre-washing or in-store misting it may have received. The FDA and food safety experts recommend washing with clean, running tap water. Scrubbing firmer produce like apples or melons with a clean vegetable brush is also advised. For produce with rinds, such as melons, washing the exterior is important to prevent transferring microorganisms to the edible parts during cutting.
Best practices for washing produce at home:
- Wash your hands with soap and water before and after handling produce.
- Rinse all produce under clean, running water. Avoid soaking, as this can recontaminate the food.
- Scrub firm-skinned items with a brush.
- Dry produce with a clean paper towel or cloth to remove remaining bacteria.
- Do not use soap, detergent, or commercial produce washes, as these have not been proven to be more effective than water and can leave harmful residue.
Conclusion
What is sprayed on produce in grocery stores, including food-safe waxes, chlorine dioxide, and antimicrobial misting agents, is a regulated and common practice to ensure food safety and quality. While these measures help extend shelf life and control pathogens from farm to table, they do not eliminate the need for proper washing at home. Understanding these processes empowers consumers to make informed choices and take the necessary steps to prepare their food safely. By prioritizing a final, thorough wash, you can confidently enjoy your fresh fruits and vegetables.
