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Fang R.,Northwest University, China | Wang Q.,Tianshui Normal University | Yang B.,Northwest University, China | Zhang J.,Northwest University, China | And 6 more authors.
Journal of Dairy Science | Year: 2015

Cronobacter spp. are opportunistic pathogens that can cause serious diseases in neonates and infants via consumption of contaminated milk powder. To determine Cronobacter spp. contamination status, 632 samples, including 15 evaporated milk, 45 intermediate powder, 150 finished products, and 422 manufacturing environment samples, were collected from 3 goat milk powder factories in Shaanxi province, China, from July 2013 to April 2014. The recovered Cronobacter isolates were subtyped using pulsed-field gel electrophoresis to trace the potential dissemination routes during the whole production processing. Sixty-seven Cronobacter spp. isolates were recovered. The prevalence rates in manufacturing environment, intermediate powder, and finished products were 92.5, 6.0, and 1.5%, respectively. The predominant species were Cronobacter sakazakii (88.1%); no Cronobacter turicensis, Cronobacter condimenti, or Cronobacter dublinensis were detected. Sixty-seven Cronobacter isolates were grouped in 26 clusters by pulsed-field gel electrophoresis, and substantial genetic similarity was observed among isolates from different sampling sites in the same factory. Isolates in the main clusters were commonly recovered from intermediate powder, floor powder, and shoes. These data indicated that air, powder, and personnel movement were potential routes for Cronobacter dissemination, and manufacturing environment is the key control point for Cronobacter contamination. © 2015 American Dairy Science Association. Source


Yang J.-J.,Northwest University, China | Guo C.-F.,Northwest University, China | Ge W.-P.,Northwest University, China | Wang Q.-N.,Northwest University, China | And 5 more authors.
Dairy Science and Technology | Year: 2014

Yak milk dreg is a popular dairy product with a unique flavor which is frequently consumed in Tibet. The aim of this study was to investigate the occurrence and distribution of yeasts in yak milk dreg of Tibet. Ninety-one yeast colonies were isolated from ten yak milk dreg samples, and the isolates belonged to seven genera and ten different species based on the phenotypic characterization and analysis of ITS/5.8S ribosomal DNA (rDNA) gene. The distribution of each species among ten samples was as follows: Kluyveromyces lactis (6/10), Pichia fermentans (6/10), Saccharomyces cerevisiae (6/10), Rhodotorula mucilaginosa (6/10), Kluyveromyces marxianus (5/10), Pichia kudriavzevii (4/10), Torulaspora delbrueckii (2/10), Torulaspora quercuum (2/10), Debaryomyces hansenii (1/10), and Cryptococcus albidus (1/10). The present study reports for the first time the yeast profile in yak milk dreg products of Tibet in China, which provides useful information and yeast strain resource for further studies involving probiotic strain selection and starter culture design for the industrial production of yak milk dreg. © 2014 INRA and Springer-Verlag France. Source


Wang Q.,Northwest Agriculture and Forestry University | Ge W.,Northwest Agriculture and Forestry University | Yuan Y.,Institution of Inspection of Xianyang Bureau of Quality and Supervision | Yang J.,Institution of Inspection of Yangling Bureau of Quality and Supervision | And 2 more authors.
Journal of Chinese Institute of Food Science and Technology | Year: 2015

Objective: To investigate the occurrence, virulence genes and antimicrobial susceptibility of Enterobacter sakazakii in goat milk powder factory. Methods: In total 180 samples including production samples and environmental samples were collected from air filtration plant, liquid milk plant, fluidized bed plant, spray drying plant and packaging plant. All samples were tested by the GB 4789.40-2010 to isolate Enterobacter sakazakii, the ompA virulence genes were detected to identify Enterobacter sakazakii by PCR; four virulence genes (sip, hly, cpa and ompX) were examined by PCR; antimicrobial susceptibility were tested by using agar dilution methods. Results: In total 29 samples of the 14 ested locations out of 27 were positive for Enterobacter sakazakii. The detection rate and the contamination rate was 51.9% and 16.1%, respectively. Positive samples mainly concentrate in the powder samples (23.5%) and swabs samples (16.9%). The rate of virulence gene was 100%. The detection rates of virulence genotypes carrying cpa-ompX and cpa-hly-ompX were 79.3% and 20.7%, respectively. The resistant rates of 29 isolates for respective antibiotics were ri-fampicin (100%), trimethoprim/sulfamethoxazole (75.9%), cefoxitin (6.9%), amoxicillin (3.4%), amoxicillin/clavulanic (3.4%). All isolates were sensitive to the other 11 kinds of antibiotics. Multiple antimicrobial resistant rate was 6.9%. Conclusion: Enterobacter sakazakii exist in the goat milk powder factory quiet easily. Distribution may be assisted by air flow, dust pollution, personnel during processing and the no thorough cleaning and disinfection of production equipment. The isolates carry a high rate of virulence genes and are sensitive to most tested antibiotics, while exist multiple antimicrobial resistance. ©, 2015, Chinese Institute of Food Science and Technology. All right reserved. Source


Fang R.,Northwest University, China | Wang Q.,Tianshui Normal University | Yang B.,Northwest University, China | Zhang J.,Northwest University, China | And 6 more authors.
Journal of Dairy Science | Year: 2015

Cronobacter spp. are opportunistic pathogens that can cause serious diseases in neonates and infants via consumption of contaminated milk powder. To determine Cronobacter spp. contamination status, 632 samples, including 15 evaporated milk, 45 intermediate powder, 150 finished products, and 422 manufacturing environment samples, were collected from 3 goat milk powder factories in Shaanxi province, China, from July 2013 to April 2014. The recovered Cronobacter isolates were subtyped using pulsed-field gel electrophoresis to trace the potential dissemination routes during the whole production processing. Sixty-seven Cronobacter spp. isolates were recovered. The prevalence rates in manufacturing environment, intermediate powder, and finished products were 92.5, 6.0, and 1.5%, respectively. The predominant species were Cronobacter sakazakii (88.1%); no Cronobacter turicensis, Cronobacter condimenti, or Cronobacter dublinensis were detected. Sixty-seven Cronobacter isolates were grouped in 26 clusters by pulsed-field gel electrophoresis, and substantial genetic similarity was observed among isolates from different sampling sites in the same factory. Isolates in the main clusters were commonly recovered from intermediate powder, floor powder, and shoes. These data indicated that air, powder, and personnel movement were potential routes for Cronobacter dissemination, and manufacturing environment is the key control point for Cronobacter contamination. © 2015 American Dairy Science Association. Source

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