Masters Theses

Date of Award

12-2015

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science and Technology

Major Professor

Doris H. D'Souza

Committee Members

Melissa A. Kennedy, Svetlana Zivanovic

Abstract

Aichi virus (AiV) is an emerging virus responsible for gastroenteritis outbreaks worldwide. Improved decontamination methods are being researched to control AiV spread. The effects of common hard surface disinfectants including benzalkonium chloride (BAC), potassium peroxymonosulfate (KPMS), tribasic sodium phosphate (TSP) as well as sodium metasilicate (SMS) and calcium hypochlorite (Ca(ClO)2) [calcium hypochlorite] against AiV need to be explored. The objective of this research was to determine their effects against AiV using suspension and carrier tests over various contact times at room temperature. Phosphate buffered saline (pH 7.2 as control), 0.64% BAC, 10% KPMS, 10% TSP, 0.16 and 0.3% NaOCl, 5 and 10% SMS, and 0.02 and 0.2% Ca(ClO)2 were mixed with equal volumes of AiV at ~ 5 log PFU/mL and treated at room temperature in suspension tests or on virus dried on formica coupons. At each time-point, treated viruses were initially serially diluted in cell-culture media containing 10% fetal bovine serum (FBS), followed by dilutions in 2% FBS. Viral infectivity was assessed by plaque assays using confluent Vero host cells. Each duplicate treatment was replicated thrice, and data were statistically analyzed. AiV was found to be reduced to non-detectable levels by 10% KPMS after 30 s in suspension, as well as in clean and simulated dirty carrier tests, and with 10% TSP after 30 min in suspension, with minimal reduction by BAC after 3 h in suspension. Additionally, AiV was reduced to non-detectable levels after 2 and 5 min with both 5% and 10% SMS in suspension, respectively and with 10% SMS after 1 min in clean carrier tests, whereas 5% SMS had a 2.78 log reduction after 5 min. Ca(ClO)2 at 0.2% and 0.02% reduced AiV to non-detectable levels after 15 s in suspension and clean carrier tests. Under simulated dirty conditions after 5 min, a 0.76 log reduction with 5% SMS, and a 1.51 log reduction with 0.2% Ca(ClO)2 was obtained, while AiV was reduced by >3 log after 1 min with 10% SMS. Overall, 10% KPMS and 10% SMS appear to be the most suitable among the tested compounds to inactive AiV, for routine decontamination purposes.


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