title: Electrostatic sprays of food-grade acids and plant extracts are more effective than conventional sprays in decontaminating Salmonella Typhimurium on spinach.
abstract: About 40000 people fall victim to Salmonella infections every year in the United States. Recent occurrences of Salmonella contaminated spinach and its recalls have accelerated the need for efficient antimicrobials targeting these pathogens. Our study was aimed at evaluating the inhibitory properties of malic, tartaric, and lactic acids, and grape seed extract (GSE) alone and in combinations and their application methods against Salmonella Typhimurium-inoculated spinach using a response surface method. Fresh spinach leaves were washed, disinfected with sodium hypochlorite solution (0.04% v/v), rewashed with sterile deionized (DI) water, and inoculated with a 2nd-day culture of S. Typhimurium (7.0 log CFU/mL). Adhered S. Typhimurium population on day 0 were 7.5 log CFU/g. These were treated with individual and combinations of organic acids with GSE or DI water (control) adjusted to the same pH as that of the test solutions with both the modes of application and leaves were refrigerated at 4 °C. Malic acid (2%) in combination with GSE (3%) or lactic acid (3%) sprayed electrostatically showed reductions of 2.6 to 3.3 log CFU/g compared to lower log reductions (0.0 to 0.3 log CFU/g) by day 14 if sprayed conventionally. These findings indicate that malic acid in combination with GSE/lactic acid solutions applied by electrostatic spraying exhibited higher inhibition of pathogens than conventional spraying and can be used for commercial applications to enhance food safety.
authors.affiliation: Dept. of Food Science, Univ. of Arkansas, Fayetteville, AR 72704, USA.
authors.forename: Vijayalakshmi
authors.initials: V
authors.lastname: Ganesh
authors.forename: Navam S
authors.initials: NS
authors.lastname: Hettiarachchy
authors.forename: Madhuram
authors.initials: M
authors.lastname: Ravichandran
authors.forename: Michael G
authors.initials: MG
authors.lastname: Johnson
authors.forename: Carl L
authors.initials: CL
authors.lastname: Griffis
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Martin
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Meullenet
authors.forename: Steven C
authors.initials: SC
authors.lastname: Ricke
mesh_terms: D018829:Adhesins, Bacterial / Q000378:metabolism; D000890:Anti-Infective Agents / Q000494:pharmacology; D058491:Bacterial Load; D003257:Consumer Product Safety; D003666:Decontamination / Q000379:methods*; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005511:Food Handling; D005519:Food Preservation / Q000379:methods; D056604:Grape Seed Extract / Q000494:pharmacology*; D019344:Lactic Acid / Q000494:pharmacology*; D008293:Malates / Q000494:pharmacology*; D010756:Phosphoric Acids / Q000494:pharmacology; D012486:Salmonella typhimurium / Q000254:growth & development* / Q000472:pathogenicity; D012973:Sodium Hypochlorite / Q000494:pharmacology; D018724:Spinacia oleracea / Q000382:microbiology; D055672:Static Electricity; D013644:Tartrates / Q000494:pharmacology*
chemical_list: D018829:Adhesins, Bacterial; D000890:Anti-Infective Agents; D056604:Grape Seed Extract; D008293:Malates; D010756:Phosphoric Acids; D013644:Tartrates; D019344:Lactic Acid; C030298:malic acid; D012973:Sodium Hypochlorite; C030242:phosphoric acid; C029768:tartaric acid