Berries are not only delicious, they contain antioxidants called anthocyanins that can protect the heart, according to the American Heart Association. But berries also tend to mold quickly when spores germinate on the humid surfaces of the fruits' skins. To reap the benefits of healthy berries and keep spoilage at bay, a simple technique using vinegar can extend the shelf life of berries by several days.
How Vinegar Works
Vinegar has been used for thousands of years, with the Babylonians and Greeks using it to preserve foods. The actual chemical process involves aerobic bacteria interacting with the alcohol in a liquid while exposed to oxygen, creating the acetic acid that gives vinegar its tang. The resulting acetic acid also has a low pH factor that kills microbes, which is why a vinegar wash can be useful in delaying spoilage and mold on berries.
Vinegar can kill harmful microbes on fresh produce, including berries, according to researchers at Tennessee State University. They published results in a 2006 issue of the "Journal of Food Protection" that found rinsing produce with a 5 percent vinegar solution in cold water was more effective at removing bacteria than lemon juice, commercial produce solutions or plain washing. The editors of "Cook's Illustrated" demonstrated in an experiment they published in a 2007 issue of the magazine that a vinegar solution removed 98 percent of bacteria on produce.
Soak for Safety
You can easily make your own vinegar solution by mixing one part white vinegar to three parts water, which is what the "Cook's Illustrated" study used. Soak the berries covered in the diluted vinegar for up to two minutes before rinsing and draining in a colander. Line a salad spinner with three layers of paper towels and spin until completely dry; moisture can be a major cause of mold growth on berries. Store berries on paper towels in a container with some ventilation to allow for air-drying.
As the "Cooks Illustrated" experiment found, although vinegar can help most bacteria, no washing technique or soaking solution can kill 100 percent of bacteria or microbes. Do not try to use bleach or detergent to further clean berries, since the fruits can absorb the chemicals. The FDA cautions against using commercial produce washes because the safety and effectiveness haven't been tested or standardized. When it comes to potentially contaminated produce, if in doubt, throw it out.
- The Kitchen Project: Vinegar
- National Public Radio: What Does It Take to Clean Fresh Food?
- Journal of Food Protection: Efficacy of Home Washing Methods in Controlling Surface Microbial Contamination on Fresh Produce
- Colorado State University: Guide to Washing Fresh Produce
- Cooks Illustrated: Caring for Berries
- Photo Credit Digital Vision./Digital Vision/Getty Images