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E. Coli O157:H7 Population Reduction from Alfalfa Seeds with Malic Acid and Thiamine Dilauryl Sulfate and Quality Evaluation of the Resulting Sprouts
Author(s) -
Fransisca Lilia,
Park Hee Kyung,
Feng Hao
Publication year - 2012
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2011.02553.x
Subject(s) - sprouting , hand sanitizer , germination , malic acid , population , chlorine , thiamine , chemistry , food science , sulfate , horticulture , biology , biochemistry , medicine , citric acid , environmental health , organic chemistry
It has been reported that washing seeds with a 20000 ppm Ca(OCl) 2 solution as recommended by the U.S. Food and Drug Administration is unable to eliminate E. coli cells attached to seed surfaces, and the bacterial cells that have survived a sanitation wash can proliferate during sprouting to a high population. The objectives of this research were to examine the efficacy of malic acid (MA) and thiamine dilauryl sulfate (TDS) combined treatments on the inactivation of E. coli O157:H7 on alfalfa seeds, to study the growth of the remaining E. coli cells during sprouting, and to evaluate the sprout quality. When 10 g of inoculated alfalfa seeds were washed in a 10% MA‐1% TDS solution, a complete elimination of E. coli was achieved. The same result was observed by washing the seeds in a 20000 ppm Ca(OCl) 2 solution. However, when the seed size was increased to 50 g while maintaining the same seed‐to‐sanitizer ratio, both the MA + TDS and the 20000 ppm chlorine washes failed to completely inactivate the E. coli cells on the seeds. Nevertheless, the 10% MA‐1% TDS solution was significantly more effective in E. coli count reduction compared to the 20000 ppm chlorine wash. The E. coli O157:H7 cells remaining on the seeds after treatments with both sanitizers grew up to 7 to 8 log CFU/g sprout after 96 h of sprouting. Under the treatment conditions used in this study, none of the treatments resulted in significant differences in germination rate, yield, or quality of the sprouts. Practical Application: The malic acid (MA) and thiamine dilauryl sulfate (TDS) combined treatment may provide a new solution to secure the microbial safety of seeds and sprouts. An important finding of this study is that seed sample size has a significant impact on the inactivation of E. coli O157:H7 on alfalfa seeds. The microbial inactivation results obtained in a laboratory set‐up cannot be directly applied to a large scale operation. A validation test on the large scale has to be performed to evaluate the efficacy of the sanitizer.