Antimicrobial Potential of Vapour Phase Acetic Acid in Combination with Ethyl Alcohol against Salmonella Typhimurium Contaminated on Bird Eye Chili (Capsicum frutescens L.)

Food Science and Technology Division, Faculty of Science and Technology, Thammasat University (Rangsit Centre), Phathum Thani, Thailand

^* Corresponding author: rtepsorn@tu.ac.th

Abstract

Bacterial contamination is the main cause of food poisoning. The currently decontamination methods arise to find novel, effective and safe approach. Acetic acid (AC) in both aqueous and vapour forms have been conducted on its effectiveness against several bacterial contaminations. The use in high concentration can cause strong smell and corrosives that have an effect on the qualities of food. This study aim to assess the potential of Mechanically Vapourized AC solution in combination with ethyl alcohol (EA) (MVA-E) on the reduction of Salmonella enterica serotype Typhimurium ATCC 13311 contaminated on both microbiological media and on fresh Bird Eye Chili (Capsicum frutescens L.). In vitro surface inhibitions of S. Typhimurium at low population, ca. 1.0 CFU/cm2, and high population, ca. 10.0 CFU/cm2 were examined on Tryptic Soya Agar (TSA). MVA-E at the concentration of 10:95 (AC:EA) presented the absolutely inhibited S. Typhimurium within 20 min at 27±2°C. At the concentration of 10:75 (AC:EA), the absolutely inactivated S. Typhimurium was observed within 10 min at 50±2°C. For the evaluation of antimicrobial activity of MVA-E over time, the results indicated that ca. 8.00 Log10 reductions were observed within 20, 25 and 25 min at the concentration of AC:EA ratio as 10:95, 10:75, and 10:45, respectively at 27±2°C. The effectiveness of MVA-E increased when the temperature of MVA-E process increased. The reduction of S. Typhimurium contaminated on fresh Bird Eye Chili by MVA-E was also determined at 4°C, 27±2°C and 50°C. The efficiency of MVA-E on the reduction of S. Typhimurium depended on the concentration of EA in MVA-E process, the fumigation time and also the temperature. To the best of knowledge this is the first time a combination of AC and EA in vapour phase has been tested as a preservative method prevent microorganism proliferation.