Efficacy of a heat-spray and heat-double spray process on inoculated nuts with Salmonella enteritidis ATCC 1045

Fredy Salazar, Sara Garcia, Manuel Lagunas-Solar, Zhongli Pan, James S Cullor

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Due to Salmonella outbreaks in almonds, regulatory standards have been established, requiring that almonds for human consumption in North America must achieve a minimum of 4 log10 CFU/g reduction of Salmonella. This study investigated a system using a combination of heating and transient application of ethanol to reduce bacterial load. This approach used a small scale heat-spray and heat-double spray process that included a two factor block design with heat (25±2 °C and 125±2 °C) and spray levels (0,1,2); One factor design with nut levels of almonds, pistachios, pecans, and walnuts for each heat-spray and heat-double spray process; a two factor experiment included a dip contact time (5s, 1800s) and ethanol evaporation time (5 s, 1800 s). Also, to evaluate the interaction of a heat-spray process on moisture content of almonds, a two factor design with levels of heat (25±2 °C and 125 ± 2 °C) and spray (0,1) was used. Additionally, the spray evaporation rate was evaluated. The heat-spray process shows additivity, while the heat-double spray process shows synergism. The heat-double spray process on almonds achieved a 6.1 mean log10 CFU/g reduction of Salmonella that was 35% higher than that of the heat-spray. For other nuts, the heat-double spray process led to a 4.8, 3.0, and 4.0 log10 reduction for pecan, pistachio, and walnut, respectively. The dip time (p < 0.05) had a greater effect than ethanol evaporation (p > 0.05) on log10 reduction of Salmonella in almonds. By applying ethanol 70%, the moisture increases by ∼0.5% w.b., whereas applying temperature decreases moisture by ∼2% w.b. The implication of these findings is that both the heat-spray and heat-double-spray process may be alternatives to the current almond disinfection processes in achieving a high log10 reduction.

Original languageEnglish (US)
Pages (from-to)74-79
Number of pages6
JournalFood Control
Volume81
DOIs
StatePublished - Nov 1 2017

Keywords

  • Ethanol
  • Food safety
  • Heat-spray phases
  • Log reduction process
  • Salmonella enteritidis

ASJC Scopus subject areas

  • Biotechnology
  • Food Science

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