Ultrasound improves chemical reduction of natural contaminant microbiota and Salmonella enterica subsp. enterica on strawberries

Int J Food Microbiol. 2017 Jan 16:241:23-29. doi: 10.1016/j.ijfoodmicro.2016.10.009. Epub 2016 Oct 11.

Abstract

New sanitization methods have been evaluated to improve food safety and food quality and to replace chlorine compounds. However, these new methods can lead to physicochemical and sensory changes in fruits and vegetables. The present study evaluated the effects of acetic acid, peracetic acid, and sodium dodecylbenzenesulfonate isolated or combined with 5min of ultrasound treatment (40kHz, 500W) on strawberry quality over 9days of storage at 8°C. The strawberry natural contaminant microbiota (molds and yeasts, mesophilic aerobic and lactic acid bacteria), physicochemical quality (pH, total titratable acidity, total soluble solids, vitamin C, and color), sensory quality (triangle test) and inactivation of Salmonella enterica subsp. enterica intentionally inoculated onto strawberries were analyzed. Ultrasound increased the effect of all chemical compounds in the reduction of aerobic mesophilic, molds and yeasts. The best treatment for those groups of microorganisms was ultrasound combined with peracetic acid (US+PA) that reduced 1.8 and 2.0logcfu/g during 9days of storage. Bactericidal effect of peracetic acid was also improved by ultrasound inactivation of S. enterica, reaching a decimal reduction of 2.1logcfu/g. Moreover, synergistic effects were observed in contaminant natural microbiota inactivation for all tested compounds during storage, without any major physicochemical or sensory alteration to the strawberries. Therefore, ultrasound treatment can improve the effect of sanitizers that are substitutes of chlorine compounds without altering the quality of strawberries during storage. Acetic acid (PubChem CID: 176); Peracetic acid (PubChem CID: 6585); Sodium dodecylbenzenesulfonate (PubChem CID: 18372154).

Keywords: Acetic acid; Peracetic acid; Salmonella enterica; Sensory quality; Synergistic effect; Ultrasound.

MeSH terms

  • Anti-Bacterial Agents / chemistry*
  • Ascorbic Acid / chemistry
  • Chlorine / chemistry
  • Chlorine Compounds / pharmacology
  • Colony Count, Microbial
  • Color
  • Disinfectants / pharmacology*
  • Food Contamination / prevention & control*
  • Food Microbiology*
  • Fragaria / microbiology*
  • Fruit / microbiology
  • Fungi / drug effects
  • Hydrogen-Ion Concentration
  • Microbiota / drug effects
  • Peracetic Acid / pharmacology
  • Salmonella enterica / drug effects*
  • Ultrasonics*
  • Vegetables / microbiology
  • Yeasts / drug effects

Substances

  • Anti-Bacterial Agents
  • Chlorine Compounds
  • Disinfectants
  • Chlorine
  • Peracetic Acid
  • Ascorbic Acid