Quantification of citrate lyase by enzyme-linked immunosorbent assay for determining the population of Lactococcus lactis subsp. Lactis biovar diacetylactis in pure and mixed cultures

David, P; Boquien, Clair‐Yves; Nakache, F.; Bassit, N.; Hartley, Dean M.; Paraf, A; Corrieu, Georges

doi:10.1007/bf00164482

Cited by 2 publications

(6 citation statements)

References 19 publications

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“…Leuc. cremoris uses citrate for the production of aroma compounds, especially in acidic conditions (David et al. 1995) and Lact.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The production of mixed cultures with external pH control is not without its problems. Detrimental interactions can occur between strains in a starter (Thunell and Sandine 1986;David et al 1995). These interactions can result in variability that should be avoided to prevent poor fermentation yields or variations in texture or flavour (Boquien et al 1988;Juillard et al 1998).…”

Section: Introductionmentioning

confidence: 99%

“…In this study, we hypothesized that citrate could substitute for phosphate in whey-based media, as citrate has been shown to stimulate the growth of Leuconostoc and Lactobacillus sp. (Cogan 1980;Boquien et al 1988;David et al 1995;Haddad et al 1997). Commercial media generally do not contain citrates, as these compounds can be fermented in the cheese, resulting in the production of CO 2 .…”

Section: Introductionmentioning

confidence: 99%

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Media and process parameters affecting the growth, strain ratios and specific acidifying activities of a mixed lactic starter containing aroma-producing and probiotic strains

et al. 2007

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Aims: The effects of medium‐composition and fermentation parameters on the properties of mixed mesophilic starters were studied. The starter was composed of Lactococcus lactis ssp. lactis (L. lactis), Lactococcus lactis ssp. cremoris (L. cremoris), Lactobacillus rhamnosus (Lact. rhamnosus) and Leuconostoc mesenteroides ssp. cremoris (Leuc. cremoris). Methods and Results: The media used were reconstituted skim milk (RSM), and whey‐based media with either citrate or phosphate buffers. The fermentation parameters were incubation temperature (22°C or 32°C), no pH control, and pH control in pH zones of either pH 6·0–5·8 or pH 6·0–5·2. The starter properties were strain ratio, specific acidifying activity (SAA), total population, residual carbohydrates and organic acids produced. The growth of L. lactis was favoured under pH control in whey‐based media. High concentrations of Lact. rhamnosus were favoured in whey‐based media prepared at 32°C. The highest contents of Leuc. cremoris were obtained in starters prepared in RSM at 22°C without pH control. Starters prepared under pH control gave the highest populations and made it possible for significantly lower inoculation rates (IR) to be used to carry out subsequent milk fermentations. However, the SAA of starters prepared under pH control were lower than the SAA of starters grown without any pH control. Conclusions: None of the conditions enabled the strain ratio at inoculation to be maintained. The data show that it is possible to prepare a mesophilic starter that has a significant probiotic Lact. rhamnosus content; this starter could be used in the preparation of probiotic‐containing cheeses or in Leuc. cremoris for aroma production in fermented milks. Significance and Impact of the Study: This study provides data on what should be expected with respect to strain ratios and IR if cheesemakers decide to shift their aroma‐producing starter production method from the traditional ‘milk‐based without pH control’ method to whey‐based media used with pH‐zone control strategies.

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“…Leuc. cremoris uses citrate for the production of aroma compounds, especially in acidic conditions (David et al. 1995) and Lact.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Media and process parameters affecting the growth, strain ratios and specific acidifying activities of a mixed lactic starter containing aroma-producing and probiotic strains

et al. 2007

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“…On the other hand phenyl ethyl alcohol agar plates are used to estimate gram positive organisms such as B. subtilis (DuTeau et al [1998]). Enzyme linked immunosorbant assay can be used to quantify specific organism in a biofilm or mixed cultures (Bauer-Kreisel et al [1996], David et al [1995]). Terminal-Restriction fragment length polymorphism has also been used to specifically quantify cells in cultures containing more than two cultures (Schmidt et al [2007]).…”

Section: Introductionmentioning

confidence: 99%

Study of CFU for individual microorganisms in mixed cultures with a known ratio using MBRT

Nandy

Venkatesh

2014

AMB Expr

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Determination of metabolically active cell count is an important step in designing, operating and controlling fermentation processes. It’s particularly relevant in processes involving mixed cultures, where multiple species contribute to the total growth. The motivation for the current study is to develop a methodology to estimate metabolically active cell counts for the individual species in a mixed culture with approximate equal numbers. Further, the methodology should indicate the presence of a contaminant in short time periods since in the agar plate methods used frequently it takes about 24 h. We present a methodology based on the rate of Methylene blue (MB) reduction to evaluate total count of metabolically active cells. The standard curve relating the slope of MB reduction and CFU of the individual species could be used to measure the metabolic activity of each species in the mixed culture. The slope of MB reduction could also be used to obtain the growth rate of individual species in a mixed culture and that of the total cell count. These measurements were achieved in less than 6 minutes during the growth of the cells. Evaluating the metabolic activity of individual species in a mixed culture is tedious, difficult and time consuming. The Methylene Blue dye Reduction Test (MBRT) presented here is capable of quickly estimating colony forming units (CFU) of individual species in a mixed culture if the ratio of the numbers of cells is known. The method was used to dynamically detect the occurrence of a contaminating microorganism during fermentation. The protocol developed here can be adapted to applications in processes involving mixed cultures.

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Quantification of citrate lyase by enzyme-linked immunosorbent assay for determining the population of Lactococcus lactis subsp. Lactis biovar diacetylactis in pure and mixed cultures

Cited by 2 publications

References 19 publications

Media and process parameters affecting the growth, strain ratios and specific acidifying activities of a mixed lactic starter containing aroma-producing and probiotic strains

Media and process parameters affecting the growth, strain ratios and specific acidifying activities of a mixed lactic starter containing aroma-producing and probiotic strains

Study of CFU for individual microorganisms in mixed cultures with a known ratio using MBRT

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