The Use of Gas Chromatography to Measure Carbon Dioxide Production by Dairy Starter Cultures

Abstract

A gas chromatographic method was developed to quantify CO2 produced by dairy starter cultures. The procedure was used to measure CO2 production by Lactococcus lactis ssp. lactis KB, a lactic dehydrogenase-deficient mutant of L. lactis ssp. lactis C2. Lactococcus lactis ssp. lactis KB produces CO2, diacetyl, and acetoin from lactose in milk. Lactococcus lactis ssp. lactis biovar. diacetylactis 18-16, which converts citrate to CO2, diacetyl, and acetoin, and L. lactis ssp. lactis C2, which does not produce CO2, were also used. Samples were introduced to the column through an injection loop. Thermal conductivity was used for CO2 detection. This method was relatively simple, results were reproducible, and CO2 production by other fermentative bacteria could be measured. © 1993, American Dairy Science Association. All rights reserved.