Antifungal activity of non-starter lactic acid bacteria isolates from dairy products

Hudecová A., Valík Ľ., Liptáková D., Pelikánová J., Čižniar M. (2011): Effect of temperature and lactic acid bacteria on the surface growth of Geotrichum candidum, Czech J. Food Sci., 29 (Special Issue): S61-S68.The surface growth of Geotrichum candidum isolated from ewes' lump cheese was studied on pure agar medium and that inoculated with lactobacillus rhamnosus GG and l. paracasei subsp. paracasei CCM 1753. The colony growth rates of fungus calculated from the growth curves were modelled in relation to temperature by the cardinal temperature model with inflection (CTMI). The following cardinal values resulted from the secondary model: t min = -3°C, t opt = 27.6°C, and t max = 35.4°C and optimal colony growth rate µ opt = 5.34 mm/day. A quantitative study also showed that the simultaneous growth of l. rhamnosus GG and l. paracasei subsp. paracasei CCM 1753 had either no or only a slight effect on the fungal growth rates, respectively. These results pointed out that other intrinsic or extrinsic factors should be applied for the protection of fresh cheeses against the undesirable growth of G. candidum.

Section: Effect Of Lab On the Surface Growth Of G Candidummentioning

confidence: 99%

Effect of temperature and lactic acid bacteria on the surface growth of Geotrichum candidum

Hudecová¹,

Valı́k²,

Liptáková³

et al. 2011

“…But anyway, the presence of lactic acid bacteria did not prevent its exponential multiplication. Lactic acid bacteria are able to assimilate nutrients from surrounding medium and produce substances such as weak organic acids (lactic and acetic acids), phenyllactic and pyroglutamic acids, carbon dioxide, hydrogen peroxide, that are often harmful for other microorganisms (Magnusson et al 2003;De Muynck et al 2004;Liptáková et al 2007Liptáková et al , 2009Voulgari et al 2010). Weak organic acids are antimicrobialy active only in the undissociated form, the concentration of which in medium is dependent on the pH.…”

Section: Growth Dynamics Of G Candidum In Co-culture With Fresco In mentioning

confidence: 99%

Quantification of Geotrichum candidum growth in co-culture with lactic acid bacteria

Hudecová¹,

Valı́k²,

Liptáková³

2009

Abstract:The growth dynamics of filamentous fungus G. candidum was studied during the co-cultivation with the commercial lactic acid bacteria (LAB) culture Fresco. The experiments were carried out in milk and on the surface of a milk agar at the temperature ranging from 5 to 37°C. Ratkowsky model was used to describe the relationships of the fungal growth rate to the temperature during both, single and co-cultivation with LAB in milk. Simultaneous growth of LAB affected significantly the growth rate of the filamentous fungus. The growth of G. candidum was in average 39% slower in the co-culture than in the single cultivation. LAB pre-inoculated and growing in the solid medium did not show any significant inhibitory effect on the surface growth of G. candidum at all tested temperature. The precise data describing the growth of this cheese yeast-like fungus, G. candidum, may fill a gap in the field of quantitative food mycology and may be used for predicting its behavior in real conditions.

“…Their preserving effect relates mainly to the formation of organic acids and H 2 O 2 , competition for nutrients and production of antimicrobial substances (Voulgari et al 2010). The acidic condition and the reduced pH of the fermented dairy products, as well as the antimicrobial activity of the undissociated lactic acid molecules, prevent the growth or survival of many spoilage and pathogenic bacteria and moulds (Carminati et al 2010;León Peláez et al 2012).…”

Section: Resultsmentioning

confidence: 99%

Lactobacilli isolated from lump sheep's cheeses and their antimicrobial properties

Smetanková¹,

Hladíková²,

Zimanová³

et al. 2014

Smetanková J., Hladíková Z., Zimanová M., Greif G., Greifová M. (2014): Lactobacilli isolated from lump sheep's cheeses and their antimicrobial properties. Czech J. Food Sci., 32: 152-157.A total of 34 strains of lactobacilli were isolated from the lump sheep's cheeses produced from raw sheep milk. The strains were identified by MALDI-TOF MS, and 20 of them demonstrating the best fermentation and sensoric properties in milk were chosen and tested for their antimicrobial activity. All selected strains were active against the indicator bacteria and moulds. The highest inhibitory effect was observed with the strains lactobacillus paracasei 314, l. paracasei 316, l. plantarum K816, l. plantarum L718, and l. plantarum 2L2. The subsequent research was focused on the metabolites causing this inhibition. The production of lactic and acetic acids was studied under different cultivation conditions (0, 2, 4, and 6.5% NaCl addition; cultivation at 15, 30, 37, and 45°C; and pH value of the broth before sterilisation 5 and 9). l. plantarum L718 produced the highest concentration of lactic and acetic acids under most of the cultivation conditions. Antimicrobial substances such as phenyllactic acid (62.54-101.62 mg/dm 3 ), H 2 O 2 (0.78-2.30 μg/cm 3 ), and diacetyl (produced by l. plantarum K816 and L718) were studied as well. Keywords: lactobacillus plantarum; lactobacillus paracasei; antimicrobial potentialIt is known that the natural microflora, present in the traditional biotechnological processes during manufacturing, participates in the production of the characteristic aroma, taste, and texture of different cheeses. At first, only artisanal starters were used for the dairy although fermentations. Although they are still used in certain cases, their microbiological instability promoted the evolution of more precisely defined mixtures of lactic acid bacteria (LAB). As cheesemaking became more industrialised, pasteurised milk and standardised bacterial and fungal inocula were introduced with the aim of obtaining a more stable acidifying activity and consistent quality of the products (Carminati et al. 2010). In spite of this trend, the production of raw milk cheeses is still significant, as consumers seek organic foods or traditional sensory characteristics. However, the diversity of microbial populations that have developed in the original cheesemaking environments is largely undefined and is a valuable source of new strains for commercial uses (Laurenčík et al. 2008). For example, non-starter LABs with the potential to inhibit the undesirable microflora are used in the biopreservation of foods (Rodríguez et al. 2000).As far as the technology is concerned, several characteristic properties of the bacterial strains of LAB (acid production in different media and at different temperatures, proteinase and peptidase activities, autolysis, production of volatile compounds, resistance to bacteriophages, production of inhibitory compounds) are important for their use as starters or adjuncts and have been evaluated in the sc...