Leuconostoc gasicomitatum is a psychrotrophic lactic acid bacterium (LAB) which causes spoilage in cold-stored modified-atmosphere-packaged (MAP) meat products. In addition to the fermentative metabolism, L. gasicomitatum is able to respire when exogenous heme and oxygen are available. In this study, we investigated the respiration effects on growth rate, biomass, gene expression, and volatile organic compound (VOC) production in laboratory media and pork loin. The meat samples were evaluated by a sensory panel every second or third day for 29 days. We observed that functional respiration increased the growth (rate and yield) of L. gasicomitatum in laboratory media with added heme and in situ meat with endogenous heme. Respiration increased enormously (up to 2,600-fold) the accumulation of acetoin and diacetyl, which are buttery off-odor compounds in meat. Our transcriptome analyses showed that the gene expression patterns were quite similar, irrespective of whether respiration was turned off by excluding heme from the medium or mutating the cydB gene, which is essential in the respiratory chain. The respiration-based growth of L. gasicomitatum in meat was obtained in terms of population development and subsequent development of sensory characteristics. Respiration is thus a key factor explaining why L. gasicomitatum is so well adapted in high-oxygen packed meat.

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Various gas chromatographic methods, which are useful for the screening of Chemical Weapons Convention (CWC)‐related chemicals, are described in this section. Proper choice of columns, detectors, and injection techniques are discussed, because they are crucial to the optimization of gas chromatography (GC) as a routine tool. Also various identification methods are described. Retention index monitoring (RIM) is described in more detail than other identification methods because it is the most reliable GC technique to be used in the identification using a retention index (RI) library without the need for an authentic chemical.

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Abstract. An identification method for chemical warfare agents using a capillary column gas chromatograph equipped with a thermal desorption cold trap injector and three different detectors is described. The most reliable identification parameters were the retention indices. The relative photoionization detectorlflame ionization detector response ratios normalized to aniline gave additional information about all compounds, whereas the response ratios calculated for the thermionic flame ionization and thermionic photoionization detection gave reliable results only for the nerve agents soman and tabun.