How can you be sure that sprouts are safe to eat?

The Controversy Over Sprouts

Since July 1999, when the U.S. Food and Drug Administration issued its first warning about the safety of raw sprouts, there has been a growing controversy about this issue. On the one hand, sprouts have some well-documented health benefits. For example, they can work better than antibiotics in preventing stomach ulcers related to overgrowth of the bacterium Helicobacter pylori. They can also help prevent stomach cancer in relationship to this same set of events.

U.S. Food and Drug Administration (FDA) Warning

At the same time, however, ingestion of radish sprouts contaminated with the bacterium E. coli O157:H7 caused the death of 17 persons in Japan in 1996, and was also responsible for illness in over 6,000 persons. This outbreak factored into the U.S. Food and Drug Administrationˇ¦s decision in 1999 to issue a warning about the dangers of eating raw or lightly cooked sprouts and recommending cooking of all sprouts to lower risk of infection. The FDA specifically mentioned alfalfa, clover, and radish sprouts in this initial warning. In 2002, it focused on mung bean and alfalfa sprouts in a renewed warning about consumption of these foods.

Since 1995, the Centers for Disease Control (CDC) in Atlanta, Georgia have reported 15 salmonella outbreaks of salmonella poisoning and two outbreaks of E coli O157:H7 poisoning in association with consumption of raw sprouts. In its renewed warning in 2002, the FDA referred to these outbreaks as further reasons to cook sprouts before eating.

How Sprouts Get Contaminated

The process of preparing, processing, and handling of raw sprouts does not appear to be the main source of potential contamination with Salmonella or E. coli bacteria. Apparently, this contamination usually involves the status of the seeds which are being sprouted. For example, use of improperly composed manure or fertilizers during seed production appears to be a likely source of bacterial contamination since bacteria-related outbreaks have usually been associated with specific seed lots (batches of seeds that can be traced through specific lot numbers). Improperly cleaned seed harvesting or processing machinery, use of untreated water during seed production, or water runoff from animal production facilities into seed production facilities can all be related to seed contamination. Once seeds have become contaminated, sprouting can make things worse, since the moisture and heat involved with sprouting can also be conducive to bacterial growth.

Even though itˇ¦s the seed production step (as opposed to the sprouting step) that seems most implicated in sprout contamination, itˇ¦s certainly not impossible for contamination to take place when the seed sprouting is not carried out in a fully sanitary way.

Practical Tip

If you do decide to keep raw sprouts in your Healthier Way of Eating for their health benefits, here are some steps you can take to help make sure that they are safe to eat:

  • Wash all sprouts thoroughly with filtered water before eating them.
  • Look for the International Sprout Growers Association seal on the package or if you are buying bulk, ask your grocery if the sprouts are ISGA-approved.
  • If the sprouts are pre-packaged, only purchase if the sell-by date is current or even a few days ahead.
  • Examine the sprouts to make sure the roots are clean. If the stem color is not white or creamy, do not purchase them. Do not purchase sprouts if the buds are no longer attached, if they are dark in color or have a musty smell.
  • Smell the sprouts to be sure that they have a clean, fresh odor.
  • Keep the sprouts refrigerated.
  • After 2 days, compost them rather than consuming them yourself.
  • If you're buying in bulk, ask your grocery about the sell date.
  • If you are sprouting seeds at home, follow the same guidelines described above. Learn about the source of your seeds, their ISGA-certification, and either have your grocery confirm high-quality standards for seed production or obtain contact information for the seed source and contact that company yourself.
  • Follow the above guidelines regardless of the type of seeds you are sprouting, i.e., apply the guidelines to mung, alfalfa, radish, broccoli, lentil, sunflower and all other types of sprouts.


Anonymous. (1999). Microbiological safety evaluations and recommendations on sprouted seeds. National Advisory Committee on Microbiological Criteria for Foods. Int J Food Microbiol Nov 15;52(3):123-53.

Fahey JW, Haristoy X, Dolan PM, et al. (2002). Sulforaphane inhibits extracellular, intracellular, and antibiotic-resistant strains of Helicobacter pylori and prevents benzopyrene-induced stomach tumors. Proc Natl Acad Sci U S A May 28;99(11):7610-5.

Kim DJ, Shin DH, Ahn B, Kang JS, Nam KT, Park et al. (2003). Chemoprevention of colon cancer by Korean food plant components. Mutat Res Feb-Mar;523-524:99-107.

Thomas JL, Palumbo MS, Farrar JA, et al. (2003). Industry practices and compliance with U.S. Food and Drug Administration guidelines among California sprout firms. J Food Prot Jul;66(7):1253-9.

This page was updated on: 2005-07-28 21:59:09
© 2002 The George Mateljan Foundation