Growing Seed Sprouts at Home
TREVOR V. SUSLOW, Department of Vegetable Crops, UC Davis; and
LINDA J. HARRIS, Department of Food Science and Technology, UC Davis.
Since 1995, raw sprouts have emerged as a significant source of foodborne illness in
the United States. These illnesses have involved the pathogenic bacteria Salmonella
and E. coli O157:H7. Alfalfa, clover, and mung bean sprouts have been involved most
frequently, but all raw sprouts may pose a risk.
For most outbreaks, the source of contamination appears to have been the seed.
Even if the seed is contaminated, pathogen levels are typically very low, so contamina-
tion can easily be missed depending on the nature of the seed-testing program. The
best conditions for sprouting are also ideal for multiplication of pathogenic bacteria if
they happen to be present on the seed. Even if the seed are only lightly contaminated,
Salmonella and E. coli O157:H7 levels can increase to millions of cells per serving dur-
ing the sprouting process.
Because illnesses from these organisms can range from mild to extremely
unpleasant and even to very severe in susceptible persons, the U.S. Food and Drug
Administration and the California Department of Health Services have issued warn-
ings to consumers:
Food and Drug Administration is advising all persons to be aware of the risks
associated with eating raw sprouts (e.g., alfalfa, clover, radish). Outbreaks have
included persons of both genders and all age categories. Those persons who
wish to reduce the risk of foodborne illness from sprouts are advised not to eat
raw sprouts.
This advice is particularly important for children, the elderly, and persons with
weakened immune systems, all of whom are at high risk of developing serious
illness due to foodborne disease. People in high-risk categories should not eat
raw sprouts. Cooked sprouts can be eaten if heated to steaming hot or above
165°F (74°C). This type of treatment is most applicable to mung bean sprouts.
HOW DOES THE SPROUT INDUSTRY ADDRESS FOOD SAFETY?
The sprout industry has been working in cooperation with industry groups, govern-
ment, and university researchers to enhance the safety of its products. These efforts
have focused on a combination of the following:
• improved seed management strategies, including use of seed that has been
grown, harvested, stored, and transported under conditions that minimize the
potential for contamination with pathogenic organisms
• seed sourced as described above, coupled with seed testing and certification
programs
• a sprouting process that follows appropriate sanitary practices, including
sanitary maintenance of facilities and equipment that will protect the product
from contamination
• treatment of seed prior to sprouting with high concentrations of calcium
hypochlorite or other disinfectants with equivalent activity
• testing of irrigation water from each production lot for Salmonella and
E. coli O157:H7
PUBLICATION 8151
UNIVERSITY OF
CALIFORNIA
Division of Agriculture
and Natural Resources
http://anrcatalog.ucdavis.edu
http://anrcatalog.ucdavis.edu
2ANR Publication 8151
Although these steps probably will significantly reduce the risk of foodborne ill-
ness associated with commercially grown sprouts, we have limited historical evidence to
back this up. Because of this, the FDA and the California Department of Health Services
still recommend that high-risk consumers avoid eating any type of raw sprouts.
GROWING SEED SPROUTS AT HOME
Sprouts grown in the home also present a risk if eaten raw, since most outbreaks have
been attributed to contaminated seed. If pathogenic bacteria are present in or on the
seed, they can multiply to high levels during sprouting even under clean conditions.
Should previously pathogen-free seed or sprouting implements (domes, trays, flats,
etc.) become contaminated in the home, the same concerns would apply as under com-
mercial growing conditions. The sprout industry currently applies a 2 percent calcium
hypochlorite solution to the seed for about 10 minutes prior to washing with clean
water and sprouting. Sodium hypochlorite (household bleach), the most common
source of chlorine in the home, is not labeled for this purpose, however, and neither is
granular calcium hypochlorite (used for treating swimming pools). Use of chlorine at
these levels is not recommended for treating seeds in the home.
The following steps are suggested for those who want to produce sprouts at home:
1. Buy certified (pathogen-free) seed* AND
2. Treat the seed by heating on the stovetop for five minutes in a solution of 3%
hydrogen peroxide (available at most drug stores) preheated to 140°F (60°C).
Use a clean, accurate cooking thermometer (preferably digital) to reach and
maintain this temperature during treatment. Typically, the small seed volumes
used for home sprouting can easily be contained in a small mesh strainer and
immersed directly into the heated peroxide solution. Swirl the strainer at one-
minute intervals to achieve uniform treatment. For larger volumes, stir the seed
occasionally during the heating process to ensure uniform temperature during
treatment. Always discard the peroxide solution after each seed batch as its
effectiveness will rapidly decline.
3. Rinse the seed in running tap water for 1 minute. In addition, we recommend
that you place the rinsed seed in a container with enough tap water to cover
the seed plus one inch. Then carefully skim off all floating seed, seed coat frag-
ments, and other debris and dispose of them. Although skimming can be a
tedious process, research has tied most contamination to these materials.
4. Sprout the seed in clean, sanitized containers, well away from areas of food
preparation, pets, and high household traffic.
To sanitize sprouting containers:
Follow the directions on the bleach container (use plain, not scented laundry
bleach) for sanitizing kitchen surfaces. Use 3⁄4 cup of bleach per gallon of water
(3 tablespoons per quart) and soak the container for at least 5 minutes. Then
rinse with clean water.
5. Follow precautions for consumption as below.
If sprouts are made in the home and eaten raw, young children, elderly persons,
or persons with weakened immune systems should NOT eat them.
* Current sources include Burpee Seed Co. (http://www.burpee.com) and Sprout People (http://www.sproutpeople.com).
If you are buying seed to sprout at home, make sure to specifically request pathogen-free certification, as the seed is
not marketed as such. Certified organic sprout seed is available from several sources, but the term “organic” does not
necessarily mean that the seed is pathogen-free or that it has been tested for pathogens. At the same time, this does
not suggest that organically grown seed poses any elevated risk of illness.
2ANR Publication 8151
http://www.burpee.com
http://www.sproutpeople.com
ADDITIONAL REFERENCES
Web sites
Information from the U.S. Food and Drug Administration for commercial sprouters:
http://www.foodsafety.gov/~dms/fs-toc.html#prod
Information from the U.S. Food and Drug Administration for consumers:
http://www.cfsan.fda.gov/~lrd/hhssprts.html
International Sprout Grower’s Association: http://www.isga-sprouts.org/
Sprout Net Archives (at International Specialty Supply): http://www.sproutnet.com/
Publications
Beuchat, L. R. 1997. Comparison of chemical treatments to kill Salmonella on
alfalfa seeds destined for sprout production. International Journal of Food
Microbiology 34:329-333.
Schrader, W. L. 2002. Sprout Production in California. Oakland: University of
California, Agriculture and Natural Resources Publication 8060.
http://anrcatalog.ucdavis.edu
Suslow, T., and M. Cantwell. Recommendations for Maintaining
Postharvest Quality: Seed Sprouts:
http://postharvest.ucdavis.edu/Produce/ProduceFacts/Veg/seedsprouts.sht…)
FOR MORE INFORMATION
You’ll find detailed information on many aspects of food safety and nutrition in these
titles and in other publications, slide sets, CD-ROMs, and videos from UC ANR:
Key Points of Control and Management for Microbial Food Safety: Edible Landscape Plants
and Home Garden Produce, Publication 8101
Tomatoes: Safe Methods to Store, Preserve, and Enjoy, Publication 8116
Home Pickling of Olives, Publication 2756
To download these products, visit our online catalog at http://anrcatalog.ucdavis.edu.
You can also place orders by mail, phone, or FAX, or request a printed catalog of publi-
cations, slide sets, CD-ROMs, and videos from
University of California
Agriculture and Natural Resources
Communication Services
6701 San Pablo Avenue, 2nd Floor
Oakland, California 94608-1239
Telephone: (800) 994-8849 or (510) 642-2431, FAX: (510) 643-5470
E-mail inquiries: danrcs@ucdavis.edu
An electronic version of this publication is available on the ANR Communication
Services Web site at http://anrcatalog.ucdavis.edu.
Publication 8151
© 2004 by the Regents of the University of California, Division of Agriculture and Natural
Resources. All rights reserved.
3ANR Publication 8151
http://www.foodsafety.gov/~dms/fs-toc.html#prod
http://www.cfsan.fda.gov/~lrd/hhssprts.html
http://www.isga-sprouts.org/
http://www.sproutnet.com/
http://anrcatalog.ucdavis.edu
http://postharvest.ucdavis.edu/Produce/ProduceFacts/Veg/seedsprouts.sht…)
http://postharvest.ucdavis.edu/Produce/ProduceFacts/Veg/seedsprouts.sht…)
http://anrcatalog.ucdavis.edu
mailto:danrcs@ucdavis.edu
http://anrcatalog.ucdavis.edu
4ANR Publication 8151
The University of California prohibits discrimination or harassment of any person on the basis
of race, color, national origin, religion, sex, gender identity, pregnancy (including childbirth, and
medical conditions related to pregnancy or childbirth), physical or mental disability, medical con-
dition (cancer-related or genetic characteristics), ancestry, marital status, age, sexual orientation,
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WARNING ON THE USE OF CHEMICALS
Pesticides are poisonous. Always read and carefully follow all precautions and safety recommendations given on the
container label. Store all chemicals in their original labeled containers in a locked cabinet or shed, away from foods
or feeds, and out of the reach of children, unauthorized persons, pets, and livestock.
Confine pesticides to the property being treated. Avoid drift onto neighboring properties or gardens containing fruits
and/or vegetables ready to be picked.
Dispose of empty containers carefully. Follow label instructions for disposal. Never reuse the containers. Make sure
empty containers are not accessible to children or animals. Never dispose of containers where they may contaminate
water supplies or natural waterways. Do not pour down sink or toilet. Consult your county agricultural commissioner
for correct ways of disposing of excess pesticides. Never burn pesticide containers.
PHYTOTOXICITY: Certain chemicals may cause plant injury if used at the wrong stage of plant development or when
temperatures are too high. Injury may also result from excessive amounts or the wrong formulation or from mixing
incompatible materials. Inert ingredients, such as wetters, spreaders, emulsifiers, diluents, and solvents, can cause
plant injury. Since formulations are often changed by manufacturers, it is possible that plant injury may occur, even
though no injury was noted in previous seasons.
pr-11/04-WJC/CR
This publication has been anonymously peer reviewed for technical accuracy by University of
California scientists and other qualified professionals. The review process was managed by the
ANR Associate Editor for Food and Nutrition.
HOW DOES the Sprout Industry ADDRESS FOOD SAFETY?
Growing Seed Sprouts at Home
ADDITIONAL REFERENCES
FOR MORE INFORMATION
Text3: ISBN 978-1-60107-321-1
