Good morning. Thank you for inviting CSPI to give this presentation on sprouts, the
outbreaks, and needed control measures. CSPI represents over one million consumers on issues
related to food safety, nutrition, and alcohol policy. To prepare for this presentation, we have
thoroughly reviewed publicly available information on outbreaks linked to alfalfa sprouts. This
review has turned up some gaps in production that put consumers at great risk. First, I would
like to review one outbreak in particular to highlight some of the lessons learned.
ANATOMY OF AN OUTBREAK
One outbreak really brought the issue of contamination of sprouts to the publics
attention. This was the other E. coli outbreak of the summer of 1997, occurring in the same
month as the outbreak that gave rise to the Hudson recall. While Hudson beef made 15 people
ill, the other outbreak was over six times as large. But unlike Hudson, there was only a limited
In early June 1997, people in Michigan and Virginia started becoming ill from E. coli
O157:H7.(1) By late July, over 100 people were sickened by this harmful strain of E. coli.(2)
Thirty-six persons were hospitalized and there were four cases of hemolytic uremic syndrome
(HUS), a life-threatening condition that can lead to kidney failure.(3) Luckily, no one died. In
both states, the illnesses were epidemiologically linked to alfalfa sprouts.(4)
Separate sprouters in Michigan and Virginia were identified as the source of the sprouts.
Inspections of the sprouters turned up no evidence of on-site contamination problems. These
inspections included environmental swab testing for E. coli O157:H7.(5) Two different seed lots
were identified as possible sources of the contaminated sprouts, and the one lot common to both
sprouters was traced to one seed distributor.
The Idaho distributor had mixed seeds from three local farms with seeds that were
harvested in the 1980s. Investigations of the local farms identified numerous places where
E. coli O157:H7 could have entered the seed supply. For example, there was a cattle feed lot
adjacent to the alfalfa field and water from adjacent fields were used on the crops. Generic
E. coli and fecal coliforms were isolated from the irrigation canals on the farm.
Further, although the seeds were soaked in a chlorine solutions to remove contamination,
the solution was significantly weaker than the amount recommended to minimize bacteria.(6)
This outbreak illustrates a number of important points about the problems with the safety
of alfalfa sprouts.
First, contaminated sprouts can cause serious and even life-threatening illnesses.
Second, the sprouters may not be the source of the problem. Contamination
frequently appears to occur earlier in the chain of production.
Third, seeds grown for use as human food must be protected from exposure to
manure, animals, and contaminated waters.
Finally, identifying the specific point of contamination in a sprout outbreak is
presently very difficult, due to the nature of sprout production.
These patterns are repeated over and over again in our review of ten outbreaks and
recalls linked to sprouts that have occurred since 1995. Most of the early outbreaks were linked
to Salmonella, so it was really a surprise to see a domestic outbreak from E. coli O157:H7. This
year, that nightmare was repeated when a non-motile strain of E. coli O157 caused an outbreak
in California. Regardless of whether it is Salmonella or harmful E. coli, pathogens in sprouts
represent an imminent hazard for consumers that the Food and Drug Administration (FDA) is
duty-bound to address.
FOOD SAFETY GAPS: SPROUT PRODUCTION
On-Farm Contamination and Related Outbreaks
Contaminated irrigation water or contact with manure is not a concern for the vast
majority of alfalfa seeds that are used in agricultural production.(7) However, for the small
proportion of seeds that are syphoned off for use for human food, such contamination is highly
The Michigan/Virginia outbreak in 1997 and a California outbreak in 1996 resulting in
over 600 illnesses both showed inadequate field conditions for the growth of human food
Cattle feed lots located next to the alfalfa fields.
Water from the irrigation canals tested positive for generic E. coli and fecal
coliforms, indicating possible contamination problems.
Chicken manure was used to fertilize the fields.
Horses were in field next to the seeds.
Manure was stored next to the field.(8)
Conditions like those are unacceptable for the growth of human foods.
Post-Farm Contamination and Related Outbreaks
Because seeds are generally not intended for use as human food, seeds are frequently
transported in open-weave sacks or other containers that dont prevent contamination after the
farm.(9) Contamination can occur in transit or at the sprouting facilities. In one investigation of a
domestic sprouting facility, investigators found rodent droppings around the seed storage area
and environmental sampling turned up evidence of Salmonella contamination in the sprouting
area. In addition, sprouting trays drained onto one another, creating ample opportunity for
cross-contamination.(10) This inspection followed a 1997 outbreak in which there were over 100
culture confirmed cases of Salmonella infection linked to the sprouts. Public health officials
believe that between 1,600 and 8,000 people became ill during this outbreak.
The investigation that followed a 1996 outbreak in which over 600 people became ill
from Salmonella and one person died revealed unhygienic sprout production practices on top of
problems on the farm. In the sprouting facility, the floors were dirty and the same buckets were
used for finished sprouts and for waste. There were unhygienic employee practices and evidence
of rodents and flies in the plant. In addition, the seed supplier usually sold alfalfa as horse feed,
and there were possible contamination points on the farm.(11) Given the warm moist growing
environment for sprouts, any one of these conditions could have resulted in an outbreak.
Following this outbreak, several sprout growers met with government officials and asked
for greater regulation of their industry, including reclassification from being agricultural workers
to being food handlers. The California Sprout Working Group, comprised of industry and
government representatives, was formed, and the group developed voluntary guidelines for
sprout production in California.(12)
Outbreaks Linked to Imported Seeds
Seeds are also imported from around the world, including China, Italy, Thailand,
Hungary, Taiwan, Pakistan, and Australia. In a 1995 Salmonella outbreak linked to alfalfa
sprouts resulting in at least 242 illnesses in at least 17 states and in Finland, the seeds were
traced through nine growers to one U.S. supplier that bought the seeds from a shipper in the
Netherlands. The seeds that came to the U.S. were reportedly a mixture of seed lots from Italy,
Hungary or Pakistan. The origin of the seeds and the harvest dates could not be determined.(13)
According to the Centers for Disease Control and Preventions (CDC) investigation, the product
coming into the shipper was full of debris. The Dutch shipper also appeared to have insanitary
conditions. There were rodents and birds in the facility and machinery. The machinery in the
plant was not routinely cleaned.(14)
Other outbreaks demonstrate that the same batch of contaminated seeds can cause
outbreaks in several countries. In one example, the first cases of Salmonella were reported in
Denmark in the summer of 1995. Cases occurred in the eastern United States in September
through November of 1995 and cases occurred in Oregon and British Columbia in December
through late February of 1996. Finally, more cases occurred in Quebec in March of 1996. The
contaminated sprouts in Oregon and British Columbia were traced to one lot of seeds that a
Kentucky supplier obtained from a Dutch shipper. The seeds from the Danish cases, which were
found to be related to the North American cases by subtyping the Salmonella strain, were traced
to a shipper in Italy.(15) Thus, the original source of that international outbreak could never be
Hurdles to Traceback and Finding a Contamination Source
The preceding examples clearly show the difficulty of conducting an effective traceback
following an outbreak. Because of the international trade, the mixing of seed, and the use of
seed stored over several seasons, it is virtually impossible to identify the contamination point for
the seeds involved in outbreaks.
ACTIONS NEEDED TO ADDRESS CONSUMER CONCERNS
While consumers have an important role to play in preventing food-safety problems,
consumers cannot prevent the outbreaks from sprouts. We can't tell consumers to eat their
sprouts fully cooked. We cant urge consumers to wash all their sprouts in chlorine bleach to
ensure their safety. This is quite simply a problem that consumers cant fix. It is up to the
industry to deliver a safe product to the consumers, or if safety cannot be assured, the industry
should alert high-risk consumers to avoid the product. CSPI has developed the following five
recommendations to address the problems that we have identified in the sprout outbreaks that we
1. Dont use alfalfa seeds unless they have been produced under conditions suitable for
The practice of using seeds that have been grown for agricultural use should stop. While
this is a profound suggestions that would likely have wide implications in the industry, the
outbreak data is clear that contaminated seeds are the overriding cause of outbreaks. While
farmers can use manure safely on alfalfa grown for agricultural production, it should be strictly
banned in the growth of seeds for human production. Farms that supply sprout growers should
observe strict guidelines for the growth of the seeds and should dedicate their seeds to the
production of human food. In addition, the practice of using seeds that have been grown in other
regions of the world should stop unless it can be demonstrated that the seeds have been produced
under suitable conditions.
2. Ban the use of mixed batches to aid traceback.
The practice of mixing batches of seeds makes traceback nearly impossible. Alfalfa
seeds intended for human consumption should be maintained in intact batches that are carried
through from the farm to the table. The batches of seeds and packages of sprouts should be
labeled or tagged for ready identification during a recall or traceback. This will help assure that
problem seeds and sprouts are readily identified and quickly removed from the market.
3. Encourage the development of safe and natural decontamination methods.
The methods currently in use, calcium hypochlorite and chlorine, are mostly reduction
steps. This means they may eliminate some harmful bacteria but others may survive the
treatment. Any treatments should be challenge tested with seeds contaminated with E. coli
O157:H7, which may be more resistant to treatment than other pathogens.(16) Other treatments,
like irradiation, may be more effective at killing bacteria but may prevent the seeds from
germinating. Today, both the industry and the government should provide honest guidance to
consumers about the effectiveness of these treatments.
4. Provide greater government oversight of the sprout industry.
The government should require that all sprout processors be registered and classified as
food handlers. Unsanitary conditions could lead to contamination of the seeds or the sprouts in
the facility, a particular problem because sprouts are grown in a warm moist environment. Thus,
sprout processors should be inspected regularly by state and federal food-safety inspectors.
HACCP is also a tool that should be considered for the sprout industry. Although there
is not now a pasteurization step, there are potential hurdles to contamination that could be
incorporated into a HACCP system.
5. Require consumer warning labels until effective controls are identified and fully
Labels on sprout containers and products should alert consumers that the product may not
be safe to serve to children, immunocompromised, and elderly consumers. CSPI has proposed a
number of labels for use on high-risk foods, such as unpasteurized apple cider, raw oysters, and
This approach was adopted by FDA for unpasteurized juices, and sprouts represent a
comparable risk. There have been eight outbreaks linked to sprouts since 1995 with at least one
death. It is unfair to leave consumers in the dark about hazards in the food supply. Until
effective controls are identified and fully-implemented, sprouts should be labeled to alert
consumers to the risk.
1. Centers for Disease Control and Prevention, Outbreaks of Escherichia coli O157:H7 Infection
Associated with Eating Alfalfa Sprouts -- Michigan and Virginia, June-July, 1997, Morbidity and Mortality
Weekly Report, Vol. 46, No. 32 (1997), pp. 741-744 [hereinafter cited as Alfalfa Sprouts Outbreak -- Michigan
2. National Advisory Committee on Microbiological Criteria for Foods, Microbiological Safety
Evaluations and Recommendations on Fresh Produce, March 5, 1998, pp. 13-14 [hereinafter cited as
Recommendations on Fresh Produce].
3. Alfalfa Sprouts Outbreak -- Michigan and Virginia, pp. 741-742; presentation of Laurence Slutsker,
Centers for Disease Control and Prevention, Overview of Recent Sprout-Associated Outbreaks in the U.S.,
(location and date to be determined) [hereinafter cited as Recent Sprout-Associated Outbreaks].
4. Alfalfa Sprouts Outbreak -- Michigan and Virginia, pp. 741-742.
6. Remarks of Dan Caudill, Caudill Seeds, at the FDA and USDA Meeting on Food Safety Research
Relevant to Produce, October 23, 1997; Alfalfa Sprouts Outbreak -- Michigan and Virginia, p. 743.
7. See e.g. Memorandum from Kate Glynn, Centers for Disease Control and Prevention, to Director,
Division of Training, Centers for Disease Control and Prevention, EPI-AID 97-56 Trip Report: An Outbreak of
Salmonella serotypes Infantis and Anatum Infections Linked to Consumption of Contaminated Sprouts, Kansas
and Missouri, February - May, 1997, Figure 4 [hereinafter cited as Outbreak Linked to Contaminated Sprouts,
Kansas and Missouri].
8. Recent Sprout-Associated Outbreaks.
9. International Sprout Growers Association, Sanitary Guidelines for the Growing & Packing for Sale of
Fresh Sprouts, November 13, 1997, p. 5.
10. Outbreak Linked to Contaminated Sprouts, Kansas and Missouri, p. 7.
11. Recent Sprout-Associated Outbreaks.
12. Letter from Patricia Griffin, Laurence Slutsker, and Robert Tauxe, Centers for Disease Control and
Prevention, to Fred Shank, Food and Drug Administration, July 29, 1997; letter from Jeff Farrar, California
Department of Health Services, to Lucy Alderton, Center for Science in the Public Interest, September 18, 1998.
13. Barbara E. Mahon et al., An International Outbreak of Salmonella Infection Caused by Alfalfa
Sprouts Grown from Contaminated Seeds, Journal of Infectious Diseases, Vol. 175 (1997), p. 879.
14. Recent Sprout-Associated Outbreaks.
15. Oregon Health Division, Salmonellosis Outbreak Traced to Alfalfa Sprouts -- Oregon and B.C., CD
Summary, Vol. 45, No. 4 (1996); telephone conversation with William Keene, Oregon Health Division, September
16. Kathleen Glass, et al., Fate of Escherichia coli O157:H7 as Affected by pH or Sodium Chloride and
in Fermented, Dry Sausage, Applied and Environmental Microbiology, August 1992, pp. 2513-2516.