Epsilon Archive for Student Projects

Abstract

Fruits and vegetables are a vital part of the human diet, and their consumption is on
the rise because they are considered as a healthy intake. However, ingredients of
fruits and vegetables are vulnerable in postharvest handling like moisture loss,
wrong handling, physical damage, and microbial contamination. Postharvest
moisture loss in fruits and vegetables affects weight, texture, appearance, acridness,
vitamins, sugar and phenolic.
Outbreaks of food borne related illnesses have been increasing during the last two
decades. Many of the diseases have been associated with leafy green vegetables
contaminated with human pathogens such as shiga toxin producing Escherichia coli
O157:H7. To eradicate the pathogens from the surfaces of vegetables and fruits in
postharvest handling, chlorine-based sanitizers treatments are widely used. But
there are some complications of using chlorine-based sanitizers for example,
producing harmful compounds like chloroform and its residual toxicity supposed
to have negative repercussions on human health. Therefore, researchers are looking
for alternative safe and less expensive methods for sanitization, one of which is the
use of blue light. In the field of microbiology recent studies showed the potential of
influencing the behavior of E. coli O157:H7 by using a certain wavelength of light
within the visible spectrum can help to kill the bacterial pathogens with a positive
effect on maintaining quality.
The main purpose of this study is to investigate the effect of blue light dose on
spinach baby leaves in terms of freshness and weight retention during shelf life. To
conduct this study, spinach leaves were exposed to blue light with a wavelength of
approximately 460 nm for 0, 2, 4, 6 and 8 hours intervals. The weight and leaf
firmness were measured after each time interval. In the control samples, the same
methodology was applied on spinach leaves without being exposed to blue light
dose. The results have shown no significant effect on spinach leaves weight and
hardness under blue light dose exposure. However, a significant loss in weight was
observed when spinach leaves were not exposed to blue light. This study has shown
that there is a possibility of using blue light as a disinfectant, but more research is
needed to optimize the dose and exposure duration of blue light so that the product
itself is not damaged in terms of quality and freshness taking into account various
factors such as growing conditions, logistics and storage climate conditions etc. The
combined effect of blue light with other light spectrums such as green and red could
be a future action point.