Sprout Food-Borne Illness Outbreaks

Until the development of ISS’s trusted and proven process for screening sprouting seeds, sprout seeds were the root cause of many outbreaks of food-borne illness. At ISS, we have been involved in the sprouts industry since its inception and have led the industry in mitigating the risks of outbreaks and making sprouts a safe food to grow and eat. This page chronicles some of the challenges our industry faced in its earliest years.

Data Concerning Historic Sprout Outbreaks

According to the Center for Science in the Public Interest, in a paper called “Outbreak Alert! 2002, “Closing the Gaps in Our Federal Food-Safety Net”, sprouts made up 7% of the outbreaks from fruit and vegetables during the period of 1990-2002 (September).

Produce Outbreaks

1990-2002

Vegetables

Potatoes 3%
Mushrooms 4%
Home-canned vegetables 5%
Sprouts 7%
Produce Dishes 9%
Other Vegetables 14%
Lettuce 11%
Salad 28%

Fruit

Melon 2%
Berries 4%
Other Fruits 13%
Total 100%

Table 1. Sprouts were suspected in 7% of the produce related outbreaks from 1990 to 2002

Sprout Related Outbreaks

Although there have been documented outbreaks in sprouts since 1973, federal regulators, public health officials, and the sprouting industry did not wake up to dangers associated with sprouting until about 1996.  All parties concerned, including ISS, were bent on coming up with a way to sanitize the seed.  Between 1998 and June 2006, there have been 36 reported outbreaks in the world that were attributed to sprouts.  Twenty-seven of which involved US and/or Canadian sprout growers.

US Sprout Related Outbreaks 1996 – 2004

(FDA figures)

Year

Alfalfa sprouts & mixes with alfalfa sprouts

Clover sprouts

Mung bean sprouts

Total

Outbreaks

Cases

1996

1

1

2

650

1997

3

3

277

1998

3

3

48

1999

5

1

6

389

2000

1

1

75

2001

1

2

3

88

2002

1

1

2

21

2003

5

5

52

2004

2

2

36

Total

21

2

4

27

1633

Table 2.  Sprouts were suspected in 27 outbreaks and 1633 cases from 1996 to May 2005

Update:  There have been additional US sprout related outbreaks reported since 2004.

Several of the Outbreaks Appear to be Related

  • Three separate bean sprout outbreaks of Salmonella were reported to be the SAME phage type. (18245289)  According to the Canada Communicable Disease Report,

“This outbreak represents the first known occurrence of SE PT 913 infection in humans.” (18)

  • Three separate alfalfa sprout outbreaks of E.coli 0157:H7 were reported to have the SAME PFGE pattern.(31101According to the investigative report,

“These Pulse patterns had never been previously identified in the United States.” (31)  

  • One outbreak reportedly involved FOUR strains of salmonella in ONE seed lot.  From the report:

“Six opened packages of alfalfa sprouts were taken from cases’ homes? Two packages were positive for S. paratyphi B var java, PT “Worksop”, PFGE pattern A1. One package was positive for S. litchfield, one for S. thompson and one for S. newport; one package was negative.” (33)

  • A 1996  outbreak appears to have matched the seed from a 1995 outbreak.  From the report on the 1996 outbreak:

“PFGE testing on four isolates from University A students and two from University B students showed them to be identical to the 1995 outbreak strain.” (117)

Sprouting Seed Often to Blame for Outbreaks

Since 1988, with one exception, seed have been the likely source of contamination in every outbreak in which the source was determined.

World Sprout Related Outbreaks 1988 – Early 2005

(Food Standards Agency, UK.)

Year

Pathogen

Cases

Location(s)

Type of sprout

Likely source of contamination

1988 S. Saint-PaulS. Havana, S.Muenchen 148 Sweden Mung ND
1988 S. Saint Paul 143 United Kingdom Mung Seed
1988 S. Virchow 7 United Kingdom Mung ND
1989 S. Gold-Coast 31 United Kingdom Cress Seed and/or sprout grower
1990 S. Anatum 15 Washington Alfalfa ND
1992 S. enterica 272 Finland Alfalfa ND
1994 S. Bovis mordificans 492 Finland, Sweden Alfalfa Seed
1995 S. Stanley 242 Finland, 6 US States Alfalfa Seed
1995 S. Newport 154 Denmark (Probably USA and Canada) Alfalfa Seed
1995 S. Newport 133 7 US States, Canada, Denmark Alfalfa Seed
1996 E. coli O157:H7 5,727 Japan Radish Seed
1996 E. coli O157:H7 126 Japan Radish Sprout growers
1996 S. Montevideo and S.Meleagridis 492 California, Nevada Alfalfa Seed and/or sprout grower
1997 S. Anatum & S. Infantis 109 Kansas, Missouri Alfalfa Seed
1997 E. coli O157:H7 79 4 US States Alfalfa Seed
1997 E. coli O157:H7 108 Michigan, Virginia Alfalfa Seed
1997 S. Meleagridis 78 Canada Alfalfa Seed (organic)
1997 S. Senftenberg 60 California, Nevada Alfalfa Seed and/or sprout drum
1998 S. Havana 18 2 US States Alfalfa Seed
1998 S. Cubana 22 5 US States Alfalfa Seed
1998 E. coli O157:H7 8 California, Nevada Alfalfa, Clover Seed and/or sprout grower
1999 S. Mbandaka 75 4 US states Alfalfa Seed
1999 S. Muenchen >157 Multistate, USA Alfalfa Seed
1999 S. Saint-Paul, 36 California, USA Clover ND
1999 S. paratyphi var Java 51 Canada Alfalfa Seed
1999 S. typhimurium 120 Colorado Alfalfa Seed
2000 Salmonella spp. 22 California, USA Alfalfa ND
2000 S. Enteritidis PT 4b 27 The Netherlands Mung Seed
2000 S. Enteritidis 75 4 US states Mung ND
2001 S. Enteritidis PT 913 84 Canada Mung Seed
2001 S. Kottbus 31 4 US states Alfalfa Seed
2002 S. Enteritidis n/a Maine Mung ND
2003 S. Saint-Paul >9 Oregon, Washington Alfalfa ND

ND = Non Determined

Table 3.  Seed was suspected in all but one of the outbreak in which a likely source was determined.

2018-11-10T03:51:37+00:00
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