EN-79AB surface disinfection by UV & effect of repetitive organisms exposure on self disinfecting chemicals

• Main Author: Enkisra, Irfan
• Other Authors: Lim Tuti Mariana
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2022
• Subjects: Engineering::Civil engineering
• Online Access: https://hdl.handle.net/10356/163422
• Institution: Nanyang Technological University

There has been an extraordinary global pandemic brought on by COVID-19. At this time, there have been more than 3 million fatalities worldwide. In addition to using masks and keeping a safe distance, many different cleaning techniques have been widely used to stop the virus’ spread in crucial areas including healthcare and food. Food packaging is one of the area where the spread of the bacteria that could affect the severity of corona virus. To minimize the spreading of bacteria, a disinfection through UV emission is considered where UV irradiation is an environmentally friendly and economical method of disinfecting plastic packaging . However, the efficacy of these methods may vary depending on various factors such as distance, duration, and UV intensity. Therefore, this project investigated the effect of UV wavelength, distance, intensity and time scale of LED(UVC) exposure as well as the performance on the growth of the bacteria at certain stage on food plastic packaging. The E.Coli k12-MG1655 have been used as the bacteria model, this is because the SARS-CoV-2 virus falls under the Biosafety Level 3 (BSL-3) category in laboratories. BSL-3 laboratory includes work on microbes that are indigenous or exotic and can induce serious or potentially lethal disease through inhalation. Covid-19 is a virus where there is no medication and the body must rely on its own immune system to fight the virus. In contrast, antibiotics can be taken to kill bacteria. Therefore, due to safety constraints, the SARS-CoV2 virus strain was not permitted to be used in this experiment. This experiment using 3 different types of UVC lamp with same wavelength under 3 different exposure distances ranging from 6cm to 12cm and 8 different timings which from 0 until 25 minutes. The study also found that disinfection can be carried out effectively when the bacteria is in the exponential growth phase. Furthermore, SEM analysis revealed negligible damage to the plastic packaging after exposure to UV radiation within a 30 minutes duration. Therefore, this study has concluded that the shorter distance, longer time span and which UVC lamp can help the minimize the spread of the bacteria without damage the plastic packaging.