Dissertation/Thesis Abstract

Inactivation of Salmonella enterica on romaine lettuce following spraying with Pro-San™—A biodegradable foodgrade sanitizer
by Drury, Julianne Elise, M.S., Iowa State University, 2011, 62; 1505842
Abstract (Summary)

The efficacy of various solutions of Pro-San™ were tested on romaine lettuce leaves against Salmonella enterica in a biofilm. Pro-San™ LC and Pro-San™ LC Soft were tested at two dilutions, 0.78% and 0.19%, at various time points and compared to a dry control and 150 ppm bleach solution, which is the currently used industry standard. Both sanitizers are bio-degradable GRAS sanitizers composed of an organic acid and a surfactant, with a pH around 2.2.

Three replicates were completed, and three variables were analyzed using SAS (Statistical Analysis Software): time, treatment, and treatment*time. The time and treatment variables had significant differences (a<0.05), but because the time*treatment variable was not significant, the ratio among the treatments was not different among the times. Therefore, Salmonella counts for each time were logged and averaged. A Tukey pairwise t-test was obtained from this data, which indicated that the dry control, distilled water control, and 150 ppm bleach solution were not significantly different from each other, but were less effective than the Pro-San™ solutions when the treatments were tested at room temperature. At refrigerated temperature, the same trend among treatments existed but only the 0.78% solutions were statistically more effective than the dry control, distilled water control, and only the 0.78% Pro-San™ was more effective than the bleach solution.

Quality effects (including color, flavor, texture, etc) were also analyzed (usind a Hunter L*a*b* colorimeter and a sensory panel), and no significant difference was observed between the treatment groups and the control groups.

The experiment was replicated with Eschericia coli O157:H7, but discontinued due to an inability to distinguish pathogenic colonies from nonpathogenic colonies on Sorbital MacConkey agar.

Indexing (document details)
Advisor: Wilson, Lester A., Mendonca, Aubrey F.
Commitee: Brehm-Stecher, Byron F., Wang, Chong
School: Iowa State University
Department: Food Science and Human Nutrition
School Location: United States -- Iowa
Source: MAI 50/04M, Masters Abstracts International
Subjects: Food Science, Microbiology
Keywords: Biofilm, Organic acid, Pro-San, Romaine lettuce, Salmonella, Surfactant
Publication Number: 1505842
ISBN: 978-1-267-15180-3
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