| 1. |
- Bett, Bernard, et al.
(författare)
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Spatiotemporal analysis of historical records (2001-2012) on dengue fever in Vietnam and development of a statistical model for forecasting risk
- 2019
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Dengue fever is the most widespread infectious disease of humans transmitted by Aedes mosquitoes. It is the leading cause of hospitalization and death in children in the Southeast Asia and western Pacific regions. We analyzed surveillance records from health centers in Vietnam collected between 2001-2012 to determine seasonal trends, develop risk maps and an incidence forecasting model.METHODS: The data were analyzed using a hierarchical spatial Bayesian model that approximates its posterior parameter distributions using the integrated Laplace approximation algorithm (INLA). Meteorological, altitude and land cover (LC) data were used as predictors. The data were grouped by province (n = 63) and month (n = 144) and divided into training (2001-2009) and validation (2010-2012) sets. Thirteen meteorological variables, 7 land cover data and altitude were considered as predictors. Only significant predictors were kept in the final multivariable model. Eleven dummy variables representing month were also fitted to account for seasonal effects. Spatial and temporal effects were accounted for using Besag-York-Mollie (BYM) and autoregressive (1) models. Their levels of significance were analyzed using deviance information criterion (DIC). The model was validated based on the Theil's coefficient which compared predicted and observed incidence estimated using the validation data. Dengue incidence predictions for 2010-2012 were also used to generate risk maps.RESULTS: The mean monthly dengue incidence during the period was 6.94 cases (SD 14.49) per 100,000 people. Analyses on the temporal trends of the disease showed regular seasonal epidemics that were interrupted every 3 years (specifically in July 2004, July 2007 and September 2010) by major fluctuations in incidence. Monthly mean minimum temperature, rainfall, area under urban settlement/build-up areas and altitude were significant in the final model. Minimum temperature and rainfall had non-linear effects and lagging them by two months provided a better fitting model compared to using unlagged variables. Forecasts for the validation period closely mirrored the observed data and accurately captured the troughs and peaks of dengue incidence trajectories. A favorable Theil's coefficient of inequality of 0.22 was generated.CONCLUSIONS: The study identified temperature, rainfall, altitude and area under urban settlement as being significant predictors of dengue incidence. The statistical model fitted the data well based on Theil's coefficient of inequality, and risk maps generated from its predictions identified most of the high-risk provinces throughout the country.
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| 2. |
- Ngo, Hai Hoang Tuan, et al.
(författare)
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Effect of light-touch intervention and associated factors to microbial contamination at small-scale pig slaughterhouses and traditional pork shops in Vietnam
- 2023
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Ingår i: International Journal of Food Microbiology. - : Elsevier. - 0168-1605 .- 1879-3460. ; 406
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Tidskriftsartikel (refereegranskat)abstract
- Traditional pork value chains dominate the production and distribution of pork in Vietnam; however, the high level of microbiological contamination in pork may increase the risk of food-borne disease for consumers. There is limited evidence about how to feasibly and scalably reduce microbial contamination in pork sold in traditional markets. This study aimed to assess the effectiveness of light-touch interventions for changing worker behaviour in small-scale slaughterhouses and vendors at traditional pork shops, as well as to identify risk factors for pork contamination. The intervention packages consisted of providing hygiene tools and delivering a food safety training which had been designed in a participatory way and covered 10 small-scale slaughterhouses and 29 pork shops. Pig carcasses, retailed pork, contact surfaces, and hands were sampled to measure the total bacterial count (TBC) and Salmonella contamination before, three and six weeks after the intervention, and trainee practices were observed at the same time. Linear and generalized linear mixed effects models were constructed to identify risk factors for TBC and Salmonella contamination at the slaughterhouses and pork shops. The interventions at slaughterhouses and pork shops both showed a slight reduction of TBC contamination in pig carcasses and Salmonella prevalence in retailed pork, while the TBC in retailed pork decreased only marginally. For slaughterhouses, the regression model indicated that smoking or eating during slaughtering (indicating poor hygienic practices) was associated with TBC increasing, while cleaning floors and wearing boots reduced TBC contamination. For pork shops, using rough materials (cardboard or wood) to display pork was the only factor increasing TBC contamination in pork, whereas cleaning knives was associated with lower TBC. Besides, the presence of supporters and wearing aprons reduced the probability of Salmonella contamination in pork. The findings highlight the effectiveness of light-touch interventions in reducing microbial contamination in pig carcasses at small-scale slaughterhouses and pork at traditional shops over the study period.
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| 3. |
- Ngo, Hai Hoang Tuan
(författare)
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Evaluating implementation strategies for improved food safety in Vietnam
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Pork is the most popular and consumed meat in Vietnam, and the preference among consumers for fresh and “warm” pork makes the traditional pork value chain dominate the pork industry. This thesis assessed microbial contamination in pork, then evaluated the technical and economic aspects of light-touch interventions in improving the safety of pork in the small-scale value chain. A total of 671 specimens of retailed pork were collected from traditional retail, modern retail, and food services to assess total bacterial count (TBC) and Salmonella prevalence. The results showed that 58% of samples were contaminated with Salmonella, and 93% of samples did not qualify for the Vietnamese standard of TBC in meat. The contamination of pork was not significantly different between the traditional and modern retail while hygiene practices were associated with lower microbial contamination. Subsequently, light-touch intervention packages were co-designed and implemented at ten small-scale slaughterhouses and 29 traditional pork shops. The packages consisted of providing tools and delivering training for participants. Results showed a reduction of TBC in pig carcasses (from 4.46 to 4.24 log10 colony forming units (CFU)/cm2, p = 0.09) and Salmonella prevalence in retailed pork (from 52% to 24% detection, p = 0.08). The upgraded pork shop was then introduced to local consumers in a Becker-DeGroot-Marschak auction game. Consumers showed a strong belief in the intervention at retail stage and were willing to pay 13,000 Vietnam Dong (VND), or 20% higher price, (p < 0.01) for each kilogram intervened pork compared to a typical one. This premium payment would cover the investment to upgrade most shops (varied from 421 to 4,146 VND/kg pork). Besides, consuming intervened pork was predicted to reduce annual risk of salmonellosis from 12% to 6%. This reduction could lead to a net benefit of 27,696,241 VND (95% CI: -546,816 – 117,515,493) for consumers and 207,788 VND (95% CI: -38,941 – 658,884) for pork sellers. This thesis provides a sustainable solution to improve pork safety across the small-scale value chain in Vietnam. An appropriate strategy to motivate these actors to implement the light-touch intervention could significantly improve the well-being of community.
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| 4. |
- Ngo, Hai Hoang Tuan, et al.
(författare)
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Impact of perception and assessment of consumers on willingness to pay for upgraded fresh pork : An experimental study in Vietnam
- 2023
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Ingår i: Frontiers in Sustainable Food Systems. - : Frontiers Media S.A.. - 2571-581X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Traditional pork shops play an essential role in delivering pork, the most popular food in Vietnam, to consumers. Studies have shown the need for investment in training and equipment to improve the safety of pork sold at traditional shops. However, it remains unclear how consumers perceived improvement to the hygiene in pork shops and if they are ready to pay premium prices for safer products. This study used an experimental approach to determine consumers’ perception and assessment of improved pork shops and their willingness to pay (WTP) for pork products. A total of 152 respondents in two provinces in Vietnam joined in a Becker–DeGroot–Marschak (BDM) mechanism experiment to collect data on WTP for pork from typical and upgraded pork shops. A questionnaire was used to record consumers’ perceptions and assessments of the pork shops and products. Overall, consumers were willing to pay 20% more for upgraded fresh pork than for what is currently available on the market. Consumers trusted in the effectiveness of the upgraded intervention and the quality of pork at the pork shop, which increased their WTP for the upgraded pork. Concerns about contaminated pork had a negative impact on the WTP for typical pork, while the high frequency of pork consumption and the existence of elderly family members led to higher WTP for both products. The findings indicate the potential economic benefit of upgrading pork shops, which would be an important driver to motivate sellers to improve food safety.
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| 5. |
- Ngo, Hai Hoang Tuan, et al.
(författare)
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Microbial contamination and associated risk factors in retailed pork from key value chains in Northern Vietnam
- 2021
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Ingår i: International Journal of Food Microbiology. - : Elsevier. - 0168-1605 .- 1879-3460. ; 346
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Tidskriftsartikel (refereegranskat)abstract
- Pork and pork products are important staple food in the diet of Vietnamese consumers. The safety of pork, including biological contamination, is a concern to several public authorities and value chain actors. This crosssectional study aimed to identify Salmonella and total bacterial count (TBC) contamination of cut pork sold in different outlets, and determine the potential factors leading to contamination. A total of 671 pork samples were collected from different retail channels in three provinces in Northern Vietnam. Hygiene conditions and practices at pork vending premises were also observed and recorded. Data analysis used descriptive statistics and regression analysis. Overall, Salmonella prevalence in retailed pork was 58.1%. Salmonella contamination in pork from traditional retail, modern retail and food services were 60.5%, 50.9% and 80.5%, respectively. Eighty percent and 68% of fresh pork in canteen and street food was contaminated with Salmonella. Only a small proportion of a subset of the pork samples (6.2%) tested met the Vietnamese standard requirement for TBC contamination. Average concentration of TBC in fresh pork in traditional retail, modern retail and food services were 6.51 (SD: 0.64), 6.38 (0.65), and 6.96 (0.85) LogCFU/g, respectively. Transport time, use of the same tools for pork and other types of meat, storage temperature, and environment hygiene are important factors that might affect microbial contamination. The findings underline the high level of microbial contamination, which requires practical interventions to improve food safety hygiene practices and behavior of pork retailers.
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| 6. |
- Ngo, Hoang Tuan Hai, et al.
(författare)
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Assessment of a light-touch intervention to reduce microbial contamination at small-scale pig slaughterhouses and traditional pork shops in Vietnam
- 2023
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Ingår i: International Journal of Food Microbiology. - : Elsevier. - 0168-1605 .- 1879-3460. ; 406
-
Tidskriftsartikel (refereegranskat)abstract
- Traditional pork value chains dominate the production and distribution of pork in Vietnam; however, there high microbiological contamination of pork may lead to health risks. There is limited evidence about how to sustainably and scalably reduce microbial contamination in pork sold in traditional markets. This study aimed to assess the effectiveness of light-touch interventions for changing worker behaviour in small-scale slaughterhouses and retailers at traditional pork shops, as well as to identify risk factors for pork contamination. The intervention packages consisted of providing hygiene tools and delivering a food safety training which had been designed in a participatory way and covered 10 small-scale slaughterhouses and 29 pork shops. Pig carcasses, retailed pork, contact surfaces, and hands were sampled to measure the total bacterial count (TBC) and Salmonella contamination and trainee practices were observed before, three and six weeks after the intervention. Linear and generalized linear mixed effects models were constructed to identify risk factors for TBC and Salmonella contamination at the slaughterhouses and pork shops. Intervention results showed a slight reduction of TBC contamination in pig carcasses from 4.46 to 4.23 log10 CFU/cm2 (p = 0.09) and Salmonella prevalence in retailed pork (reduction from 52% to 24% detection, p = 0.08), while the TBC in retailed pork decreased only marginally (5.47 vs. 5.36 log10 CFU/g, p = 0.23). For slaughterhouses, the regression model indicated that smoking or eating during slaughtering was a risk factor, associated with TBC increasing by 0.60 log10 CFU/g (95% confidence interval (CI): 0.12 to 0.96, p =0.02), while cleaning floors and wearing boots reduced TBC contamination with 0.53 log10 CFU/g (CI: –0.83 to 0.01, p = 0.03) and 1.04 log10 CFU/g (CI: –1.50 to –0.26, p = 0.03), respectively. For pork shops, using rough materials (cardboard or wood) to display pork was the only factor increasing TBC contamination in pork with 0.57 log10 CFU/g (CI: 0.22 to 0.91, p < 0.001), whereas wearing aprons was associated with lower TBC, with 0.45 log10 CFU/g (CI: –0.79 to –0.12, p = 0.02), and Salmonella contamination in pork (odds ratio (OR) = 0.13, CI: 0.02 to 0.72, p = 0.03). The findings highlight the effectiveness of light-touch interventions in reducing microbial contamination in pig carcasses and pork over the study period.
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| 7. |
- Ngo, Hoang Tuan Hai, et al.
(författare)
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The cost-benefit analysis of a light-touch intervention to improve the safety of pork in Vietnam : the case of salmonellosis
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Salmonellosis is a common food-borne disease in low and middle-income countries but there is not much cost-effective program to reduce its burden, even in developed countries. This study aims to estimate the cost of salmonellosis in Vietnam and analyse the net benefit of light-touch intervention at small-scale pork shop in reducing the burden of salmonellosis. The cost of light-touch intervention cost at 29 pork shops was collected as well as the prevalence of salmonellosis severity in Hung Yen and Thai Nguyen. The Monte Carlo simulation was implemented to estimate the cost of salmonellosis, cost and benefit pork sellers and consumers. Sensitivity analysis was conducted to identify the most influenced factors to the net benefit of both two stakeholders. The cost of salmonellosis in Vietnam was calculated to be 345,770,000 VND per case (95% CI: 52,151 – 8,533,360,000). The total net benefit of the light-touch intervention was 27,900,000 VND per year (95% CI: -43,000 – 117,700,000) with 59.6% of positive cases. Most of this benefit was transferred to the consumers: 27,700,000 VND per year (95% CI: -550,000 – 117,520,000) with 61.2% of cases being positive while the figure of pork seller was 210,000 VND per year (95% CI: -39,000 – 660,000) with 93.2% positive cases. The pork seller was mostly profitable due to implementing the intervention while the consumer’s benefit varied strongly following the change of salmonellosis probability and the cost of salmonellosis
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