Hostname: page-component-7c8c6479df-995ml Total loading time: 0 Render date: 2024-03-28T00:53:08.417Z Has data issue: false hasContentIssue false

pH-Sensing 96-well microtitre plates for the characterization of acid production by dairy starter cultures

Published online by Cambridge University Press:  21 July 2003

Gernot T John
Affiliation:
Technische Biochemie, Saarland University, 66123 Saarbrücken, Germany
Detlef Goelling
Affiliation:
Danisco Cultor Niebüll GmbH, D-25899 Niebüll, Germany
Ingo Klimant
Affiliation:
Institut für Analytische, Chemo- und Biosensorik, Universität Regensburg, D-93040 Regensburg, Germany
Holger Schneider
Affiliation:
Danisco Cultor Niebüll GmbH, D-25899 Niebüll, Germany
Elmar Heinzle
Affiliation:
Technische Biochemie, Saarland University, 66123 Saarbrücken, Germany

Abstract

A new method for characterization of acid production by dairy starter cultures is presented. Microplates with integrated optical pH sensors are developed. Two fluorophores, a pH-sensitive and a pH-insensitive one are immobilised at the bottom of a polystyrene 96-well microtitre plate. The pH-insensitive fluorophore serves as an internal reference and makes calibration unnecessary. The sensor measures pH accurately in optically well-defined media. Particles and fluorophores contained in the bulk medium disturbed the measurements. Despite these disturbances it was possible to clearly sense differences in inoculum type and in inoculum sizes of cultures of Lactococcus lactis and of Streptococcus thermophilus at 30 and 37°C. Besides a pH-related signal there is information about other changes during milk fermentation. The cultivation results were compared with those from the established CINAC-method. From this comparison it can be concluded that the new method can be used reliably to characterize particularly a large number of strains for screening purposes but also for quality control.

Type
Research Article
Copyright
Proprietors of Journal of Dairy Research 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)