Determination and Improvement of Microbial Safety of Wheat Sprouts with Chemical Sanitizers

Abstract

In this study, total aerobic mesophilic bacteria (TAMB), total coliform (TC), yeasts and moulds (YM), and Escherichia coli, Salmonella, and Staphylococcus aureus counts of wheat seeds and sprouts germinated for 9 days under different relative humidity (RH) (90% and 95%) and temperatures (18 °C, 20 °C, and 22 °C) were determined. The disinfection capabilities of sodium hypochlorite (NaOCl) (100, 200, and 400 ppm) and hydrogen peroxide (H(2)O(2)) (3% and 6%) on wheat seeds/sprouts were also investigated. It has been found that native TAMB, TC, YM, and E. coli population significantly increased (p<0.05) with the germination; however, no Salmonella and S. aureus were detected on the seeds and/or sprouts. Again, increasing the temperature and RH resulted in a rapid proliferation of microorganisms. On the other hand, E. coli population could be completely eliminated by the treatment of different concentrations of NaOCl or H(2)O(2) before the germination of wheat seeds. Again, increasing the NaOCl and H(2)O(2) concentrations resulted in additional reductions of TAMB, TC, and YM population; and the highest reductions in sprouts were observed when the seed was soaked in 400 ppm NaOCl for 30 minutes followed by tap water wash and germination for 9 days. Population reduction of 1.46 log colony-forming unit (cfu)/g of TAMB, 1.97 log cfu/g of YM, and 0.84 log cfu/g of TC in sprouts was achieved when compared with the control. The chemical sanitization did not negatively affect the germination capability of the seeds. Therefore, soaking the seeds in 400 ppm of NaOCl for 30 minutes followed by a germination environment of 18 °C and 90% RH was found to be the most appropriate germination condition for wheat sprouts with reduced microbial population.