Validation of di-electric heating as a potential food safety intervention
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Date
2014-11
Authors
Luvanda, Maureen K.
Journal Title
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Abstract
Food and water borne diseases are leading causes of illness and death in less
developed countries killing approximately 7.2 million people annually, 1.9 million of
whom are children. WHO has estimated that each year 2.2 million people, including
1.9 million children, die because of diarrheal diseases. This study was intended to
experimentally analyze if di-electric heating has any indirect impact on the control,
management and prevention of food borne disease outbreaks in terms of reduction of
bacteria infective doses and increase in antibiotic susceptibility. This included
investigating the effects on bacterial colony forming unit counts before and after
exposure to microwave radiation as well as investigating changes in antibiotic
susceptibility patterns. Surviving colonies were also investigated for viability, growth
and multiplication ability. The aim of the study was to determine if microwave
radiation can be used as a food safety intervention; whereas other objectives included
evaluating its effects on growth and multiplication of bacteria. reduction of bacterial
infective doses, measuring appropriate time (in minutes) required for radiation to
achieve the desired results, recording the most effective power at which radiation was
most likely to achieve the desired results and lastly observing if there are any
significant changes as a result of exposure to microwave radiation when it comes to
antibiotic susceptibility patterns. Various food samples (n=73) were artificially
contaminated by food borne disease pathogens (Escherichia coli, Staphylococcus
aureus, Shigella flexneri and Salmonella paratyphi) and were exposed to microwave
radiation at different powers (P-OO, P-20. P-40, P-60, P-80) and time periods (2 rnin,
4 min, 6 min, 8 min).The degree of inactivation was estimated by measuring the
colony forming units formed in culture before and after exposure of samples to
radiation (Pre-test Post-test experimental design). The laboratory methods used were
mainly culture techniques and biochemical tests. Data entry was done in Microsoft
Excel after which data analysis was carried out using Statistical Package for Social
Science (SPSS V 13) software. The results showed that generally microwave radiation
produced a 1-2 log reduction when artificially contaminated food samples were
processed. Initial seeded bacterial numbers (>3.0 x 104
) were reduced significantly
I' (P<0.05) however, this was not the same case when it came to antibiotic susceptibility
patterns. The most effective time-power combination for bacteria inactivation was 8
minutes at P-80 where bacteria numbers were very low «1.0 x 10\ whereas the least
effective time-power combination for bacteria inactivation was 2 minutes at P-20
where bacteria numbers remained at (>3.0 x 104).The study shows that microwave
radiation reduces infective doses of bacteria by 96.67% but does not affect their
antibiotic susceptibility patterns. Indications of any other effects of microwave
radiation on the microbial agents were als noted. This study will serve as a guide to
policies implemented on management and control of food and water borne infections.
Traditional methods for improvements in food safety are still being utilized however
the number of food and water borne disease incidences and antibiotic-resistance cases
continue to rise. This therefore means that prevention rather than cure is important
now more than ever and so modern methods or practices such as the microwave
radiation that promote food hygiene should be explored and encouraged.
Description
Department of Medical Laboratory Sciences, 118p. 2014