Epsilon Archive for Student Projects

Abstract

The issue of sickness and death as a result of foodborne illness is a health concern spread
worldwide. This indicates the need for effective antimicrobial technologies within the food
industry. Photodynamic inactivation (PDI) is a technology which utilizes the overproduction
of reactive oxygen species (ROS) within pathogens by activating endogenous
photosensitizers, where the oxidative stress generated by ROS in turn leads to cell death. This
paper has investigated the effect of blue light PDI on Escherichia coli O157:H7 gfp+ where
the change in growth as well as changes of gene expressions have been explored. The results
indicated that a wavelength of 420 nm generated the highest reduction of colony forming
units per ml (CFU/ml). In addition, longer exposure to blue light also resulted in a higher
reduction of CFU/ml. Refrigerating the samples further reduced the CFU/ml. On average, a
percentage reduction of 91.9-95.5% of CFU/ml was observed in the treated samples. The
findings of this research emphasizes the possible benefits of the implementation of blue light
PDI in the food industry. However, due to the novelty of this technology, more research is
required to ensure consumer completely safe food products.