Agriculture Reference
In-Depth Information
Table 20.1.
Outbreaks of foodborne illness related to leafy greens, 1992-1996
Date
Product
Pathogen
Cases
Setting/Dish
State
Apr - 92
Lettuce
Salmonella enteriditis
12
Salad
VT
Jan - 93
Lettuce
Salmonella
Heidelberg
18
Restaurant
MN
Jul - 93
Lettuce
Norovirus
285
Restaurant
IL
Aug - 93
Salad
E. coli
O157:H7
53
Salad bar
WA
Jul - 93
Salad
E. coli
O157:H7
10
Unknown
WA
Sep - 94
Salad
E. coli
O157:H7
26
School
TX
Jul - 95
Lettuce
E. coli
O153:H48
74
Lettuce
MT
Sep - 95
Lettuce
E. coli
O153:H47
30
Scout camp
ME
Sep - 95
Salad
E. coli
O157:H7
20
Salad
ID
Oct - 95
Lettuce
E. coli
O153:H46
11
Salad
OH
May - 96
Lettuce
E. coli
O157:H10
61
Mesclun mix
CT/IL
Jun - 96
Lettuce
E. coli
O153:H49
7
Mesclun mix
NY
that pathogens can enter lettuce plants through its roots and end up in the edible leaves.
Small gaps in growing roots through which plant pathogens infect tissue may also allow
E. coli
entry (Solomon and others 2002b; Warriner and others 2003a; Warriner and
others 2003b). This research has been well known and publicized in mass media.
The 1993 outbreak of
E. coli
O157:H7 associated with undercooked hamburgers
at the Jack-in-the-Box fast-food chain propelled microbial food safety to the forefront
of public awareness, at least in the U.S. (Leiss and Powell 1997). In 1996, following
extensive public and political discussions about microbial food safety in meat, the
focus shifted to fresh fruits and vegetables following an outbreak of
Cyclospora cay-
etanesis
linked to Guatemalan raspberries that sickened 1,465 in 21 U.S. states and
two Canadian provinces (CDC 1997). That same year, Beuchat (1996) published a
review on pathogenic microorganisms in fresh fruits and vegetables and identifi ed
numerous pathways of contamination.
By 1997, researchers at CDC were stating that pathogens could contaminate at any
point along the fresh produce food chain, at the farm, processing plant, transportation
vehicle, retail store or foodservice operation, and the home, and that by understanding
where potential problems existed, it was possible to develop strategies to reduce the
risks of contamination (Tauxe and others 1997). Researchers also reported that the use
of pathogen-free water for washing would minimize risks of contamination (Suslow
1997 ; Beuchat 1998 ).
Beuchat and Ryu (1997) reported in a review that sources of pathogenic micro-
organisms for produce included the following:
Preharvest
•
Feces
•
Soil
•
Irrigation water
•
Water used to apply fungicides, insecticides
•
Green or inadequately composted manure
•
Air (dust)
•
Wild and domestic animals (including fowl and reptiles)
