Three Washington Illnesses Linked to Oregon Salmonella Outbreak in Alfalfa Sprouts

Three Washington Illnesses Linked to Oregon Salmonella Outbreak

Washington Department of Health
23 February 1999

OLYMPIA, Wash. — State and federal agencies continue to work on the Salmonella outbreak linked earlier this month to contaminated alfalfa sprouts grown at Hydro Harvest Ltd., a sprout producer in Brush Prairie, Wash.

The same strain of Salmonella that sickened 18 people in Oregon now has been confirmed as the cause of illness for three Washington residents. Hydro Harvest, Ltd. voluntarily recalled its alfalfa sprout products Feb. 12.

The microbiology labs at the state departments of Health and Agriculture today announced that 10 of 11 alfalfa sprout samples and one alfalfa seed sample taken from Hydro Harvest, Ltd. have tested positive for Salmonella. Further tests are underway to confirm whether the sprout and seed samples contain the same Salmonella strain as the stool samples from patients.

“For now, anyone who has sprouts in their refrigerator should check the label to see where they came from,” said Dr. Maxine Hayes, acting state Health Officer. “If the sprouts came from Hydro Harvest, they should be thrown out immediately.”

Investigators from the state Department of Agriculture and the U.S. Food and Drug Administration inspected Hydro Harvest, Ltd. Feb. 12 and 13. Contaminated alfalfa sprouts were discarded, and several corrections in three broad categories were recommended: decontaminate the facility and production equipment, increase the amount of chlorine used to disinfect seed, and set up procedures to prevent future contamination of sprouts.

Agriculture investigators confirmed Friday that the corrections were made, and Hydro Harvest, Ltd. started producing sprouts from a new lot of seeds. Samples of new sprouts will be collected today and tomorrow for testing.

Although the recall is nearly complete, as late as last week some of the sprouts had not been removed from sale in a few locations. State and federal agencies continue to work with the producer to make sure all potentially contaminated sprouts are removed from distribution.

Lab tests conducted at the State Health Laboratories in Shoreline definitively confirm that three Washington patients were infected from Hydro Harvest sprouts. A DNA fingerprinting test showed that the stool samples taken from Washington and Oregon patients have the exact same strain of Salmonella mbandaka as sprouts that were produced by Hydro Harvest and obtained from the home of an Oregon patient. Several other Washington cases of Salmonella are under investigation due to exposure to contaminated sprouts.

Cases of Salmonella mbandaka are not common in Washington. An average of 2.5 cases occur each year and are reported to the state Department of Health. Infection with any strain of Salmonella bacteria can cause sudden headache, abdominal pain, diarrhea, nausea, and vomiting. Dehydration may be severe, especially among infants or in the elderly, and fever is common. The condition often persists for several days. The incubation period is usually about one to three days.

According to Hayes, the three Washington cases occurred in residents of Thurston, Cowlitz, and Clark counties. “That doesn’t mean that people in other areas of Washington should disregard the warning,” she said. “If you have any sprouts in your fridge, find out where they came from before you eat them.”

Bert Bartleson, Technical Expert for the Food Program at the Washington State Department of Health, warns consumers, “Because so many outbreaks of illness have been linked to sprouts recently, persons at high risk for severe infection should stop eating sprouts. Higher risk of infection and more severe symptoms are most common in persons who have cancer and are on chemotherapy, are HIV positive, or have a weakened immune system for any other reason.”

Hayes said that anyone who was ill with severe diarrhea, abdominal cramps and fever and who ate this brand of sprouts should consider being cultured for Salmonella. They should also report their illness to the local health department in their county, she said.

The contaminated sprouts were sold between Nov. 1998 and Feb. 12, 1999 through wholesalers to many grocery stores, restaurants, and other retail outlets in Oregon and Washington in 6-oz. plastic “clamshell” packages labeled as “Living Alfalfa Sprouts,” “Living Salad Sprouts: Alfalfa/Radish/Clover,” and “Living Onion-Alfalfa Sprouts.” All 6-oz. packages carry the Hydro Harvest name, and are carried by many supermarkets and other grocery stores, including Safeway, Fred Meyer, and Thriftway. The sprouts are also sold in bulk as 1 lb. trays or 2 lb. plastic bags.

Consumers who have purchased alfalfa sprout products produced by Hydro Harvest, Ltd. are urged to return them to the place of purchase for a full refund. Consumers with questions may contact Hydro-Harvest, Ltd. at 360/260-9617.

Foodborne Illness,E. Coli, and Food Processing Issues

Salmonella and Alfalfa Sprouts

University of Washington, Seattle Washington

The main reason I want to talk about this Salmonella outbreak is that it illustrates the strategy of combining epidemiologic work and environmental health work with trace back of food products and using your results to develop further public health prevention strategies. This was an outbreak of Salmonella with cases in Washington, Oregon, and Idaho. These Salmonella cases were related to consumption of alfalfa sprouts. The cases all had the same DNA fingerprint and there were also positive specimens of sprouts and sprout seeds that were identified, which also had the same DNA fingerprint.

In addition to the outbreak investigation, a trace back occurred with regards to where these alfalfa sprout seeds came from. It was subsequently found that a producer in the Imperial Valley in southern California was the source of this seed. Interestingly, it was found that the sprout seed that was sent to Washington State was also sent to Florida and several locations in California. However, there were no subsequent cases of salmonellosis related to sprouts produced in those areas, and we were looking quite carefully for cases in those areas.

First some background information on sprouts. One of the big problems with regards to foodborne diseases and sprouts is that it is very difficult to control bacterial contamination of sprouts. When sprouts are produced, the seed is soaked, and then they are put in an incubator drum where the seeds sprout and grow. It is a warm environment with plenty of nutrients, an ideal place for bacteria to multiply. It has been found that very large numbers of bacteria are produced. If you count all bacteria on finished sprouts, they may have 108 to 109 bacteria per gram. Very few of these are pathogenic bacteria. The problem is that if you have a pathogenic bacteria in the seed to begin with, even with a very small amounts of pathogenic bacteria, those can multiply and produce significant amounts in the finished product. People have tried disinfecting the seeds with various chlorine solutions and chemicals and by doing so, the resulting seeds are not viable. There are many outbreaks that have happened over the past several years, and alfalfa sprouts carry a similar risk to that of consuming raw shellfish: most of the time you are OK, but occasionally there are problems.

Outbreaks with sprouts fall into this area of the new scenario outbreaks. These outbreaks tend to be scattered. Very frequently, sprouts are not a major item on the menu but are a condiment in sandwiches, so it may be difficult for people to identify that they actually ate sprouts. Furthermore, E. coli O157:H7 and Salmonella survive extremely well in seed. They can survive for years in the seed. These seeds are transported widely across international borders, certainly across state lines, so you have dispersed outbreaks.

One of the items discovered during the outbreak was that we had contaminated seed from a particular lot. Some of the sprouters did not have outbreaks, and one sprouter did. An interesting factor with regards to this particular sprouter is that he was not using the chemical solution called calcium hydrochloride. Some sprouters have been soaking their seed in 20,000 parts per million calcium hydrochloride before they sprout them. The sprouters in Florida and California were using this method. This person was not. So that generated considerable excitement among the regulatory agencies and sprouters because perhaps this method may be helpful. Twenty thousand parts per million calcium hydrochloride, I have been told, is a very vile chemical solution, and sprouters do not like using the chemical very much, but that appears to be one of the main methods of intervention. This is a good example of how epidemiology and environmental health, with regards to how these seeds were produced and distributed can be used to have a better understanding of to deal with this problem.


FDA and Oregon Human Resources
February 14, 1999


Portland – Public health official announced a recall of Hydro Harvest brand alfalfa and mixed sprouts from retail outlets throughout Oregon and Washington. “These alfalfa sprouts have been identified as the cause of an ongoing outbreak of salmonellosis,” said Dr. William E. Keene, epidemiologist at the Oregon Health Division. “Consumers who have them in their refrigerators should discard them immediately.”


To date, 11 persons infected by Salmonella serotype Mbandaka have been identified in Oregon. “The number of cases has increased steadily over the past few days, however, and laboratory-confirmed cases are usually just the tip of the iceberg,” Keene said.


The contaminated sprouts were produced by Hydro Harvest, Ltd., of Brush Prairie, Washington, and distributed through a number of wholesalers to many grocery stores, restaurants, and other retail outlets in Oregon and Washington. “Hydro Harvest has agreed to recall its alfalfa sprouts voluntarily,” Keene said. State and federal agencies are working with the producer to remove potentially contaminated sprouts from distribution. While none of this product has been reported in Alaska, some stores receive their produce from hub distributors in Oregon and Washington. Retailers and wholesalers who hold any of the recalled sprouts should segregate them from other produce and contact Hydro Harvest for additional information. Restaurant and deli operators should check their stock immediately to identify and pull any of the recalled product.


The recall covers all alfalfa sprouts produced by Hydro Harvest since November 1998. These sprouts have been sold in 6-oz. plastic “clamshell” packages labeled as “Living Alfalfa Sprouts,” “Living Salad Sprouts: Alfalfa/Radish/Clover,” and “Living Onion-Alfalfa Sprouts.” All 6-oz. packages carry the Hydro Harvest name and are carried by many supermarkets and other grocery stores, including Safeway, Fred Meyer, and Thriftway. The sprouts are also sold in bulk as 1-lb trays or 2-lb plastic bags.


Salmonellosis is an acute bacterial infection that can cause diarrhea, fever, and vomiting. Symptoms usually develop within one to four days after eating contaminated food. Most cases resolve without the need for medical attention. People who have eaten sprouts and developed severe symptoms should discuss this exposure with their doctor. Some persons with salmonellosis develop serious illness that can lead to hospitalization and even death.



Recall Notice

Alfalfa sprouts and sprout mixes: a) Alfalfa Sprouts, in 6 ounce “clam shell” containers, 1 pound plastic trays, and in 2 pound cardboard cases; b) Salad Sprouts (alfalfa/radish/clover), packed in 6 ounce “clam shell” containers; c) Onion-Alfalfa Sprouts, packed in 6 ounce “clam shell” containers. Recall #F-212/214-9.

All codes on the market at the time of the recall.

Hydro Harvest Ltd., Brush Prairie, Washington.

Manufacturer, by telephone and by press release on February 12, 1999. Firm-initiated recall complete.

Oregon, Washington state, California, Idaho.

Approximately 3,000 – 3,500 units of sprouts are distributed every other day.

Products were associated with an outbreak of salmonellosis.