Bean sprouting refers to the process of soaking beans in water, allowing them to set at room temperature and rinsing them once or twice a day until sprouts form. The number of days required before the sprouts can be eaten depends on type of bean, temperature and humidity, although most beans sprout in two or three days. Advocates of sprouting claim that bean sprouts contain higher concentrations of vitamins and minerals than the beans they come from; however, there is no scientific evidence to support this claim. Eating some raw bean sprouts may pose health risks, but most can be eaten without worry.
Types of Sprouts
Mung beans are among the most common types of beans sprouted in the United States -- packaged, fresh, raw mung bean sprouts are commonly available in groceries and health foods stores. Canned mung bean sprouts are also available; however, canning typically involves heat, so canned mung sprouts may not be raw. Lentil and soybean sprouts are also enjoyed by many.
Mung bean sprouts may offer high concentrations of phenolic compounds, which are antioxidants, according to an article published in "Revisita de Nutricao." They are also a low-calorie food -- a 1-cup serving of raw mung bean sprouts contains only about 31 calories.
Eating raw bean sprouts may increase your risk of bacterial infection. Raw sprouts may become contaminated with bacteria, including Salmonella and E. coli, when beans come in contact with animal manure during growth or storage. The warmth and moisture required to sprout beans provides an environment in which bacteria can easily multiply. Salmonella infection can cause symptoms that include abdominal cramps, nausea, headaches and vomiting. E. coli may produce similar symptoms, and may cause permanent kidney damage in rare cases.
Beans purchased from grocery stores for sprouting may likewise be contaminated. Although tedious, washing the beans with distilled water and a vegetable scrubber before sprouting may reduce the risk of sprout contamination.
Children, the elderly and people with impaired immune system function are at the greatest risk of infection from consuming raw bean sprouts. If you choose to consume raw sprouts, refrigerate them at a temperature below 40 degrees Fahrenheit and discard them as soon as they lose their crispness, after about two or three days, to minimize the risk of bacterial infection.
- University of Cincinnati Clermont College: Sprouting Seeds; David B. Fankhauser, Ph. D.
- "Revisita de Nutricao"; Total Phenolics and Antioxidant Activity of the Aqueous Extract of Mung Bean Sprout ; Vera Lucia Arroxelas Galvao de Lima, et al.; 2004
- U.S. Department of Agriculture: Nutrient Data Laboratory; Mung Beans; Mature Seeds; Sprouted; Raw