ABSTRACT
Objective:To investigate a foodborne brucellosis outbreak in a county in Guangdong Province in 2015， which may provide suggestions for the prevention and control of similar incidents. Methods:Case search was carried out by visiting cases， accessing the hospital medical record system， and collecting the registration information of rural health stations， and the results were described and analyzed. Results:A total of 169 cases were found， with an attack rate of 2.0‰ （169/85 000）. The onset time of the cases was from January 19 to June 2， 2015， showing a continuous and homogenous outbreak pattern. The clinical manifestations of the cases were fever （72%）， fatigue （40%）， hyperhidrosis （26%）， testicular enlargement （5.3%）， headache （2.4%）， and hepatomegaly （1.2%）. In addition， 54 cases of latent infection were found. A total of 13 strains of brucella ovis type 3 were cultured from the patients’ serum samples. After all sheep in the farm were sampled， 16 samples of serum test tube agglutination test were positive， with a positive rate of 37% （16/44）； after analysis， drinking fresh goat milk was a risk factor for brucellosis （OR=36.25， 95%CI： 4.68-280.73）， and there was a dose-response relationship between infection and milk drinking （χ2=27.00， P<0.05）. Conclusion:The brucellosis outbreak was caused by patients who drank unboiled goat milk contaminated with Brucella ovine type 3. People are recommended to drink qualified and sterilized goat milk. Relevant government departments should strengthen the monitoring of goat selling and goat milk production.
ABSTRACT
Objective: Taking single Liuwei Dihuangwan(LDW) as the research object,the moisture content change and volumetric shrinkage characteristics in its drying process were investigated,which provided the theoretical basis for improving the drying efficiency of the pills and reducing the quality problems of the pattern pills,crusts and crack pills. Method: The drying characteristics of LDW at drying temperature of 50,75,100,125℃ were studied by constant temperature hot air drying and vacuum drying.Based on sphere model of Fick's second law and Arrhenius equation,the effective diffusion coefficient and activation energy of the drying process were obtained.The volumetric shrinkage characteristics of the pills during the drying process were studied by the projected area method.The Weibull function was used to fit the drying dynamics curve of single LDW. Result: Hot air drying and vacuum drying of LDW both belonged to the decreasing drying processes,and the time required to achieve the same moisture content in vacuum drying was shorter than that in hot air drying.The moisture ratio in the drying process of single LDW obeyed the Weibull function distribution(R2=0.994 5-0.999 7),the scale parameter(α) decreased with the increase of temperature,and drying temperature had significant influence on the shape parameter (β).The effective diffusion coefficients of hot air drying and vacuum drying were 2.626×10-3-7.823×10-2,3.782×10-3-9.042×10-2 m2·s-1, their activation energy were 47.18,42.69 kJ·mol-1,respectively.The volume ratio of hot air drying and vacuum drying of LDW ranged from 0.638 to 0.741 and 0.607 to 0.689,respectively. Conclusion: Weibull function can be adopted to predict the drying and dehydration law of LDW.Under the condition of low temperature drying,slow-down of shrinkage rate of the pills is helpful to prevent the formation of splitting pills,this study provides theoretical and technical basis for dying of LDW.