Remarks of Caroline Smith DeWaal
Director of Food Safety
FDA’s Public Meeting to Review

at the Current Science Relating to Sprouts and
Needed Control Measures

September 28, 1998
Washington, DC
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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.


One outbreak really brought the issue of contamination of sprouts to the public’s 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 recall.

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 1980’s. 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.

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.


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 problematic.

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 including:

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 don’t 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 Prevention’s (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 fully determined.

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.


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 can’t urge consumers to wash all their sprouts in chlorine bleach to ensure their safety. This is quite simply a problem that consumers can’t 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 have examined.

1. Don’t use alfalfa seeds unless they have been produced under conditions suitable for human consumption.

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 implemented.

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 eggs.

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 and Virginia].

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.

5. Ibid.

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, 1998.

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.