Prevalence and Risk Assessment of Salmonella Spp. in Sliced Fruit

Fresh fruits and vegetables are increasingly recognized as a source of salmonellosis outbreaks in many parts of the world. Such products are always eaten raw or with minimal processing and if contaminated with Salmonella, they may represent a health hazard to the consumers. The public health importa...

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Main Author: Pui, Chai Fung
Format: Thesis
Language:English
Published: 2011
Online Access:http://psasir.upm.edu.my/id/eprint/19654/1/FSTM_2011_2.pdf
http://psasir.upm.edu.my/id/eprint/19654/
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Institution: Universiti Putra Malaysia
Language: English
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spelling my.upm.eprints.196542014-05-15T02:02:07Z http://psasir.upm.edu.my/id/eprint/19654/ Prevalence and Risk Assessment of Salmonella Spp. in Sliced Fruit Pui, Chai Fung Fresh fruits and vegetables are increasingly recognized as a source of salmonellosis outbreaks in many parts of the world. Such products are always eaten raw or with minimal processing and if contaminated with Salmonella, they may represent a health hazard to the consumers. The public health importance of Salmonella in man led the present study to determine the prevalence and quantity of Salmonella spp., Salmonella Typhi and Salmonella Typhimurium in sliced fruits. In domestic kitchen, the food contact surfaces are sometimes improperly cleaned which ease the formation of biofilm by Salmonella. Subsequent detachment from the biofilm layer can be at risk for contamination of fresh fruits and vegetables. Hence, the quantification of biofilm formed by Salmonella Typhi and Salmonella Typhimurium on plastic cutting board used in domestic kitchen was determined in this study prior to analyzing the transfer rate of these two pathogens to the fruit model. The most probable number (MPN)-multiplex polymerase chain reaction (PCR) was used for the prevalence and quantification studies. A multiplex PCR was optimized for the simultaneous detection of Salmonella spp., Salmonella Typhi and Salmonella Typhimurium in sliced papaya, watermelon, mango, sapodilla, jackfruit, dragon fruit and honeydew. The prevalence of Salmonella spp., Salmonella Typhi and Salmonella Typhimurium in 210 samples of sliced fruits examined were 23.3%, 7.6% and 3.8%, respectively with estimated quantity varied from 0 to 19 MPN/g. On the other hand, the prevalence of Salmonella spp. discovered from the total sliced fruits of hawker stalls were three times higher than those from hypermarkets at 30% and 10% respectively at p<0.05. Salmonella spp. were detected in 23.3% fruit samples using MPN-multiplex PCR and at 9.5% using MPN-plating method. Out of the seven types of fruits examined, dragon fruit from hawker stalls showed the highest prevalence of contamination with 75% Salmonella spp., 40% Salmonella Typhi and 25% Salmonella Typhimurium. Hence, it was used as the fruit model to study the biofilm formation by Salmonella Typhi and Salmonella Typhimurium on plastic cutting board and their subsequent transfer to dragon fruit. By using crystal violet assay, it was found that biofilm formation of Salmonella Typhi and Salmonella Typhimurium on plastic cutting board was the highest at 12 h when they are incubated in physiological saline solution at 28°C. On the transfer of these two pathogens from plastic cutting board to dragon fruit, results showed their mean transfer percentages were 92.38 and 91.30%respectively for Salmonella Typhi and Salmonella Typhimurium. These highlighted that biofilm can cross-contaminate dragon fruit and contribute to cross-infection. As a conclusion, there is a need for the health authority to look into the risk assessment of sliced fruits in Malaysia. The risk of microbial transfer from food contact surface to fresh fruits should also be of concern to prevent foodborne disease outbreaks. 2011-03 Thesis NonPeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/19654/1/FSTM_2011_2.pdf Pui, Chai Fung (2011) Prevalence and Risk Assessment of Salmonella Spp. in Sliced Fruit. Masters thesis, Universiti Putra Malaysia.
institution Universiti Putra Malaysia
building UPM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Putra Malaysia
content_source UPM Institutional Repository
url_provider http://psasir.upm.edu.my/
language English
description Fresh fruits and vegetables are increasingly recognized as a source of salmonellosis outbreaks in many parts of the world. Such products are always eaten raw or with minimal processing and if contaminated with Salmonella, they may represent a health hazard to the consumers. The public health importance of Salmonella in man led the present study to determine the prevalence and quantity of Salmonella spp., Salmonella Typhi and Salmonella Typhimurium in sliced fruits. In domestic kitchen, the food contact surfaces are sometimes improperly cleaned which ease the formation of biofilm by Salmonella. Subsequent detachment from the biofilm layer can be at risk for contamination of fresh fruits and vegetables. Hence, the quantification of biofilm formed by Salmonella Typhi and Salmonella Typhimurium on plastic cutting board used in domestic kitchen was determined in this study prior to analyzing the transfer rate of these two pathogens to the fruit model. The most probable number (MPN)-multiplex polymerase chain reaction (PCR) was used for the prevalence and quantification studies. A multiplex PCR was optimized for the simultaneous detection of Salmonella spp., Salmonella Typhi and Salmonella Typhimurium in sliced papaya, watermelon, mango, sapodilla, jackfruit, dragon fruit and honeydew. The prevalence of Salmonella spp., Salmonella Typhi and Salmonella Typhimurium in 210 samples of sliced fruits examined were 23.3%, 7.6% and 3.8%, respectively with estimated quantity varied from 0 to 19 MPN/g. On the other hand, the prevalence of Salmonella spp. discovered from the total sliced fruits of hawker stalls were three times higher than those from hypermarkets at 30% and 10% respectively at p<0.05. Salmonella spp. were detected in 23.3% fruit samples using MPN-multiplex PCR and at 9.5% using MPN-plating method. Out of the seven types of fruits examined, dragon fruit from hawker stalls showed the highest prevalence of contamination with 75% Salmonella spp., 40% Salmonella Typhi and 25% Salmonella Typhimurium. Hence, it was used as the fruit model to study the biofilm formation by Salmonella Typhi and Salmonella Typhimurium on plastic cutting board and their subsequent transfer to dragon fruit. By using crystal violet assay, it was found that biofilm formation of Salmonella Typhi and Salmonella Typhimurium on plastic cutting board was the highest at 12 h when they are incubated in physiological saline solution at 28°C. On the transfer of these two pathogens from plastic cutting board to dragon fruit, results showed their mean transfer percentages were 92.38 and 91.30%respectively for Salmonella Typhi and Salmonella Typhimurium. These highlighted that biofilm can cross-contaminate dragon fruit and contribute to cross-infection. As a conclusion, there is a need for the health authority to look into the risk assessment of sliced fruits in Malaysia. The risk of microbial transfer from food contact surface to fresh fruits should also be of concern to prevent foodborne disease outbreaks.
format Thesis
author Pui, Chai Fung
spellingShingle Pui, Chai Fung
Prevalence and Risk Assessment of Salmonella Spp. in Sliced Fruit
author_facet Pui, Chai Fung
author_sort Pui, Chai Fung
title Prevalence and Risk Assessment of Salmonella Spp. in Sliced Fruit
title_short Prevalence and Risk Assessment of Salmonella Spp. in Sliced Fruit
title_full Prevalence and Risk Assessment of Salmonella Spp. in Sliced Fruit
title_fullStr Prevalence and Risk Assessment of Salmonella Spp. in Sliced Fruit
title_full_unstemmed Prevalence and Risk Assessment of Salmonella Spp. in Sliced Fruit
title_sort prevalence and risk assessment of salmonella spp. in sliced fruit
publishDate 2011
url http://psasir.upm.edu.my/id/eprint/19654/1/FSTM_2011_2.pdf
http://psasir.upm.edu.my/id/eprint/19654/
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