C Vasilopoulos

Publications (2)5.35 Total impact

• Article: Kinetics of growth and 3-methyl-1-butanol production by meat-borne, coagulase-negative staphylococci in view of sausage fermentation.

  F Ravyts, G Vrancken, K D'Hondt, C Vasilopoulos, L De Vuyst, F Leroy
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  ABSTRACT: Five species of meat-borne, coagulase-negative staphylococci were screened for their in vitro production of 3-methyl-1-butanol. The highest production level was encountered for Staphylococcus sciuri alphaSG2, despite its poor growth. With respect to Staphylococcus species that are generally applied in sausage starter cultures, production of 3-methyl-1-butanol was higher with Staphylococcus xylosus 3PA6 than with Staphylococcus carnosus 833. Mathematical modelling was used to link the kinetics of 3-methyl-1-butanol production by S. xylosus 3PA6 and S. carnosus 833 in meat simulation medium to bacterial growth and environmental factors, in casu temperature and pH. The specific production rate of 3-methyl-1-butanol was about ten times higher for S. xylosus 3PA6 than for S. carnosus 833, indicating a higher production rate per amount of biomass. This explains the higher concentrations of 3-methyl-1-butanol in the medium with S. xylosus 3PA6, despite its poorer growth.
  International journal of food microbiology 03/2009; 134(1-2):89-95. · 3.01 Impact Factor
• Article: Evaluation of the spoilage lactic acid bacteria in modified-atmosphere-packaged artisan-type cooked ham using culture-dependent and culture-independent approaches.

  C Vasilopoulos, F Ravyts, H De Maere, E De Mey, H Paelinck, L De Vuyst, F Leroy
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  ABSTRACT: To investigate microbial diversity and population dynamics of spoilage-sensitive modified-atmosphere-packaged (MAP) artisan-type cooked ham in relation to storage temperature. Modified-atmosphere-packaged cooked ham samples were stored at different temperatures (4, 7, 12 and 26 degrees C). Traditional methods were combined with polymerase chain reaction (PCR)-based techniques, i.e. a culture-dependent, repetitive DNA sequence-based method (rep-PCR) and a culture-independent approach (PCR-denaturing gradient gel electrophoresis of 16S rRNA gene fragments; PCR-DGGE). rep-PCR on DNA extracted from MRS isolates indicated that Leuconostoc carnosum and Enterococcus faecalis prevailed at all temperatures, with the latter becoming more important above 7 degrees C. PCR-DGGE indicated the additional presence of Carnobacterium divergens and Brochothrix thermosphacta at all temperatures. Discriminant analysis related variation within the Leuc. carnosum cluster to the storage temperature. High performance liquid chromatography revealed that lactic acid was the main metabolite because of glucose consumption. Leuconostoc carnosum, C. divergens, E. faecalis and Br. thermosphacta are the main spoilage bacteria of artisan-type MAP cooked ham. Their population dynamics are affected by storage temperature. Temperature can condition the development of spoilage in artisan-type MAP cooked ham, acting at both species and biotype level.
  Journal of Applied Microbiology 06/2008; 104(5):1341-53. · 2.34 Impact Factor