Evaluation of biofilm-forming abilities of Listeria monocytogenes (ATCC 19115) and efficacy of different washing methods for removal of biofilm on apple

Y Ali,C.S Kuan,C.H Kuan,P Azizi,C.Y New,H.Y Mah,Son Radu,E.T Phuah,S.K Yeo,S.N Chen

doi:10.26656/fr.2017.5(4).037

Abstract

Fresh produce can be contaminated at any stage along the food supply chain. In this study, apple was chosen to determine the time course of biofilm formation by Listeria monocytogenes (ATCC 19115), as well as to compare the efficacy of different household washing methods such as scrubbing with hands under running tap water, soaking with and without commercial vegetable wash with different treatment times in removing the biofilm formation by L. monocytogenes on apple surface. The biofilm formation was quantified using crystal violet assay and the result showed that L. monocytogenes took 18 hrs to form matured biofilm on apple surface. Besides, scrubbing apples with hands under running tap water for 30 s and 60 s were the most effective method which significantly removed (P<0.05) biofilm formed on the apple surface with approximately 5.93 log reduction. Soaking apples with vegetable wash for 5 mins and 10 mins were also found to be significantly effective (P<0.05) in reducing L. monocytogenes biofilm. Since L. monocytogenes can form matured biofilm on fresh produce, therefore efficient washing step is important before consuming fresh produce to lower the risk of foodborne illness.

Highlights

Foodborne illness is a disease caused by consuming food or water contaminated with pathogens including viruses, bacteria, parasites and other microorganisms (Feltes et al, 2017)
The biofilm formation by L. monocytogenes on the apple surface was observed over 24 hrs
Findings indicated that L. monocytogenes can form matured biofilm on the apple surface after 18 hrs

Summary

Introduction

Foodborne illness is a disease caused by consuming food or water contaminated with pathogens including viruses, bacteria, parasites and other microorganisms (Feltes et al, 2017). It is a pathogenic bacterium that can be found in ready-to-eat food, cold-stored food, dairy products, and processed food. This pathogen will cause listeriosis which is a dangerous infection resulting in a high mortality rate of 20% to 30%, and more than 90% of patients with listeriosis are hospitalized (United States Food and Drug Administration, 2020). The elderly, pregnant woman, infants, and toddlers are the vulnerable groups that are susceptible to listeriosis (Kuan et al, 2013). Listeriosis can lead to serious infection which can spread to the brain causing encephalitis and meningitis. Pregnant women with listeriosis can have a miscarriage or premature birth (Castellazzi et al, 2018)

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Conclusion