Comparison of Aqueous Chemical Treatments to Eliminate Salmonella On Alfalfa Seeds

Comparison of Aqueous Chemical Treatmentsto Eliminate Salmonella on Alfalfa Seeds

October 2000
Journal of Food Protection: Vol. 63, No. 11, pp. 1475­1482.
Center for Food Safety and Quality Enhancement, Department of Food Science andTechnology, University of Georgia, 1109 Experiment Street, Griffin, Georgia30223-1797, USA



Thisstudy was undertaken to evaluate various chemical treatments for theireffectiveness in killing Salmonella on alfalfa seeds. Immersing inoculated seedsin solutions containing 20,000 ppm free chlorine (Ca[OCl]2), 5% Na3PO4, 8% H2O2,1% Ca(OH)2, 1% calcinated calcium, 5% lactic acid, or 5% citric acid for 10 minresulted in reductions of 2.0 to 3.2 log10 CFU/ g. Treatment with 1,060 ppmTsunami or Vortex, 1,200 ppm acidified NaClO2, or 5% acetic acid were lesseffective in reducing Salmonella populations. With the exceptions of 8% H2O2, 1%Ca(OH)2, and 1% calcinated calcium that reduced populations by 3.2, 2.8, and 2.9log10 CFU/g, respectively, none of treatments reduced the number of Salmonellaby more than 2.2 log10 CFU/g without significantly reducing the seed germinationpercentage.

Treatmentwith 5% acetic, lactic, or citric acids substantially reduced the ability ofseeds to germinate.

Treatmentwith 1% Ca(OH)2 in combination with 1% Tween 80, a surfactant, enhancedinactivation by 1.3 log10 CFU/g compared to treatment with 1% Ca(OH)2 alone.

Presoakingseeds in water, 0.1% EDTA, 1% Tween 80, or 1% Tween 80 plus 0.1% EDTA for 30 minbefore treatment with water, 2,000 ppm NaOCl, or 2% lactic acid had a minimaleffect on reducing populations ofSalmonella.

Resultsindicate that, although several chemical treatments cause reductions inSalmonella populations of up to 3.2 log10 CFU/g initially on alfalfa seeds whenanalyzed by direct plating, no treatment eliminated thepathogen, as evidenced by detection in enriched samples.