The question What about soaking greens in vinegar?
A. It won’t kill the bacteria, but some experts say that soaking your greens in white vinegar (or a vinegar and water solution) for 10 minutes, then rinsing them in water, can help reduce bacteria levels. Your greens may retain a slightly vinegary taste, but most salad dressings contain vinegar.
The question Are some types of lettuce safer than others?
A. Because contamination can occur anywhere from farm to table, no type of leafy green is risk-free. But hydroponic lettuces (those grown in a greenhouse) are less likely to be contaminated with bacteria from animal droppings. Their cleanliness depends on the source of the water used to grow them and whether people handling the greens follow proper safety practices, said James E. Rogers says.
Whole heads of lettuce (rather than bagged greens) are safer. While whole heads may not have lower levels of bacteria than bagged greens, their inner leaves are less exposed to sources of contamination and require less handling than bagged greens. This reduces the risk of contamination.
The question What else can you do to keep your lawn safe?
A. Bacteria thrive at room temperature, so it’s important to refrigerate bagged spinach immediately. “Just like you would with meat and poultry, don’t let bagged spinach sit out of the fridge too long,” says Rogers.
Also, the longer lettuce sits in bags or containers, the more opportunity for bacteria to grow, so buy packages with expiration dates as far in the future as possible, and don’t buy more than you can eat in a few days. If even a few leaves look damaged, limp, or bruised, don’t eat any of the greens in that package.
Another trick: Choose leafy greens that can be cooked like spinach or kale. Heat kills bacteria. This is especially important for people who are more susceptible to the ill effects of food poisoning, such as those with weakened immune systems, pregnant women, and the elderly.