Strategy to achieve a 5-log Salmonella inactivation in tender coconut water using high voltage atmospheric cold plasma (HVACP)

Nikhil Kumar Mahnot; Charu Lata Mahanta; Kevin M Keener; N N Misra

doi:10.1016/j.foodchem.2019.01.084

Strategy to achieve a 5-log Salmonella inactivation in tender coconut water using high voltage atmospheric cold plasma (HVACP)

Food Chem. 2019 Jun 30:284:303-311. doi: 10.1016/j.foodchem.2019.01.084. Epub 2019 Jan 19.

Authors

Nikhil Kumar Mahnot¹, Charu Lata Mahanta², Kevin M Keener³, N N Misra⁴

Affiliations

¹ Department of Food Engineering and Technology, School of Engineering, Tezpur University, Assam, India; Department of Food Sciences, Purdue University, West Lafayette, IN, USA.
² Department of Food Engineering and Technology, School of Engineering, Tezpur University, Assam, India. Electronic address: charu@tezu.ernet.in.
³ Department of Food Sciences, Purdue University, West Lafayette, IN, USA; Center for Crops Utilization Research, Iowa State University, Ames, IA, USA; BioCentury Research Farm, Iowa State University, Ames, IA, USA. Electronic address: kkeener@iastate.edu.
⁴ Center for Crops Utilization Research, Iowa State University, Ames, IA, USA. Electronic address: misrann@iastate.edu.

PMID: 30744862
DOI: 10.1016/j.foodchem.2019.01.084

Abstract

This study examined high voltage atmospheric cold plasma (HVACP) technology as a non-thermal intervention for inactivating Salmonella enterica serovar Typhimurium LT2 (ST2) in tender coconut water (TCW). Treatment with HVACP in air at 90 kV for 120 s inactivated 1.30 log₁₀ of ST2. Development of a TCW stimulant suggested an interfering role of magnesium and phosphate salts with HVACP inactivation. Generation of reactive gas species, viz. ozone and hydrogen peroxides were found to be responsible for microbial inactivation. The addition of 400 ppm citric acid to the TCW effectively reduced ST2 by 5 log₁₀ during HVACP treatment. Under these conditions, higher cellular leakage and morphological damage were observed in ST2. Minimal physico-chemical changes in TCW were observed with HVACP treatment, except for an 84.35% ascorbic acid loss (added externally). These results demonstrate a potential pathway for developing highly effective cold plasma treatments to preserve fruit and vegetable juices.

Keywords: Ascorbic acid; Citric acid; Coconut; Cold plasma; Electrical discharge; Minerals; Non-thermal.

MeSH terms

Ascorbic Acid / pharmacology
Citric Acid / pharmacology
Cocos / chemistry*
Food Microbiology
Fruit and Vegetable Juices / analysis*
Microbial Viability / drug effects
Nitrogen Dioxide / chemistry
Nitrogen Dioxide / pharmacology
Ozone / chemistry
Ozone / pharmacology
Plasma Gases / pharmacology*
Salmonella typhimurium / drug effects*

Substances

Plasma Gases
Citric Acid
Ozone
Ascorbic Acid
Nitrogen Dioxide