International Specialty Supply
Supplying Sprout Companies Throughout the World
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International Specialty Supply Supplying Sprout Companies Throughout the World
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Evaluations
of Disinfectants for Control of Pathogens in Alfalfa Seeds & Sprouts Reference
Type: Conference Proceedings Abstract:
Outbreaks of infections associated with raw fruits and vegetables have occurred
with increased frequency during the past decade. At least fourteen outbreaks of
Salmonella and Escherichia coli O157:H7 infections linked to the consumption of
alfalfa sprouts, clover sprouts, and mungbean sprouts have been documented since
1995. The level of safety risk associated with sprouts that are not cooked
before eating has raised interest in evaluating a wide range of chemicals for
their efficacy in killing pathogens on seeds intended for sprout production and
on mature sprouts. Test chemicals have included chlorine (hydochlorous acid),
chlorine dioxide, acidified sodium chlorite, various organic acids, trisodium
phosphate, calcium hydroxide, hydrogen peroxide, ethanol, volatile plant
compounds, and several commercial formulations. While treatment with some of
these chemicals has been shown to reduce populations of Salmonella and E. coli
O157:H7 by more than 6 log10 CFU/g, substantial loss of seed viability also
often occurs. Treatment of alfalfa seeds with 20,000 ppm chlorine (as calcium
hypochlorite), 1% calcium hydroxide, 500 ppm acidified sodium chlorite, and a
prototype produce wash (Fit7) are most effective in reducing pathogens without
sacrificing germination percentage. The delicate nature of alfalfa sprouts
renders them extremely sensitive to chemical treatment. Gaseous acetic acid (500
ppm) and allyl isothiocyanate (200 ppm) reduce the number of Salmonella on
alfalfa sprouts by about 7 log10 CFU/g but also adversely affect color, turgor,
and overall appearance. Among the aqueous chemical treatments applied to alfalfa
sprouts, acidified sodium chlorite shows the most promise. Disinfection of seeds
before sprout production remains a unique challenge in terms of developing
interventions for eliminating pathogenic bacteria without reducing yield or
compromising sensory quality of mature sprouts. Combinations of chemical and
physical treatments are currently being investigated on the assumption that
multiple assaults will enhance lethality to pathogens that apparently are
occasionally present in low numbers on alfalfa seeds. |