Microbiological risk assessment of microwave heating on ready-to-eat foods
The microwave oven is an inexpensive multifunctional device commonly used for reheating purpose during meal preparation. The safety level of microwave heated foods remains in vague due to consumers’ lack of awareness and knowledge on microwave heating the food safely. This research study aimed...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2017
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/68826/1/FSTM%202018%201%20IR.pdf |
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| Summary: | The microwave oven is an inexpensive multifunctional device commonly used for
reheating purpose during meal preparation. The safety level of microwave heated
foods remains in vague due to consumers’ lack of awareness and knowledge on
microwave heating the food safely. This research study aimed to scientifically address
the microbiological safety of microwave heated ready-to-eat (RTE) foods. To initiate
the study, a consumer survey study was conducted to measure the Malaysian’s
consumers’ knowledge and practice microwave oven safety. Next, the survivability of
Salmonella enterica and Shiga-toxigenic Escherichia coli (STEC) O157 in microwave
heated RTE foods was studied to identify the risk factors and subsequently evaluate
the risk factors. The prevalence of the foodborne pathogens’ survivability in
microwave heated RTE foods was investigated using the Most Probable Number
coupled Polymerase Chain Reaction (MPN-PCR) method. The highest possibility of
the foodborne pathogens’ survival was due to factors affecting the microwave heating
in particular presence of cold spots, microwave heating time and consumers’
knowledge; all identified as risk factors. In the food safety context, microwave heating
time and consumers’ knowledge was given more attention. The microwave heating
time on the influence of different food composition in relation to bacteria inactivation
was then studied and the data was used to model the bacterial inactivation using the
Weibull model. These studied risk factors were then incorporated into a retail and
consumer phase exposure assessment model to estimate the risk of consumption of
contaminated RTE food reheated at different microwaving times using @risk. The
outcome of the study showed that the respondents demonstrated low level of
knowledge and safety practice of the microwave oven, although they had neutral
attitude on food safety. Out of the 329 samples of various convenience meals collected
around Wilayah Persekutuan Kuala Lumpur and Selangor regions, 20.1% were tested
positive with Salmonella spp. and 5.2% with STEC O157. Fats were observed to have
the highest influence to the microwave heating time compared to proteins and
carbohydrates. Based on the overall food composition, the results indicated that the foodborne pathogens were fully inactivated by microwave heating at 60 seconds as no
viable growth was observed. However, the risk assessment model estimated probable
foodborne illness cases for RTE food microwave heated less than 90 seconds for S.
enterica serovar Enteritidis and STEC O157 exposure assessment models. The
outcome indicated that RTE food should be microwave heated up to 90s and more to
ensure the safety of the food and other interventions such as controlling the holding
temperature and having a fixed display holding time. The current risk research study
provided comparative information on the evaluation of microwave technology in
terms of food safety. Notably, foodborne pathogens can survive the microwave
heating which put the consumers at risk when improper safety practice and usage of
the microwave oven is taken. The implementation of microwave heating guidelines,
involving the safe microwave heating time and safety practice, into food safety
educational programs should be established as risk interventions and further to
conserve the public health. |
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