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The effect of whey powder, whey protein concentrate, caseinomacropeptide, and malt addition into milk on the growth and acid production of lactobacilli (Lactobacillus casei Lafti L-26, Lactobacillus acidophilus CCDM 151, and Lactobacillus casei CCDM 198) was evaluated. The ability of these strains to use different types of saccharides from milk and plant sources was also tested. Glucose, galactose, fructose and maltose were utilised by all tested strains. The results showed that the addition of malt positively affected the growth of lactobacilli strains compared to the growth in milk enriched by whey ingredients. The addition of malt increased significantly the production of D(-) isomer of lactic acid by Lactobacillus acidophilus CCDM 151 and Lactobacillus casei CCDM 198 and the production of acetic acid by Lactobacillus casei CCDM 198. [ABSTRACT FROM AUTHOR]

The antifungal effects of lauric acid and four lauric acid derivatives (monolauroylglycerol, D-laurate A, T-laurate A, 6- O-lauroysucrose) were tested on the spore germination and the growth rate of Aspergillus niger DMF 0801. The results showed that the tested substances varied in their antifungal activity and they also confirmed the relation of the structure of tested substances and their antifungal effects. Monolauroylglycerol at concentration level between 0.2 and 1.8 mmol l–1 caused the highest inhibition of spore outgrowths whereas 6- O-lauroysucrose at concentration between 0.05 and 1.8 mmol l–1 did not exhibit inhibition of spore germination. The inhibition of colony growth rate was detected mainly at presence of 6- O-lauroysucrose. [ABSTRACT FROM AUTHOR]

About 300 strains were isolated from different sources and phenotypically identified. Twenty-three of them, identified as Lactococcus lactis, were subjected to genotypic characterization and tested for autolytic activity. These strains were subdivided by the plasmide profile technique into 4 clusters, each containing the isolates that shared the same plasmid pattern. Three strains showed completely different plasmid profiles. Three highly autolytic strains were found among 23 isolates. One of them, Lactococcus lactis HMM81, which exhibited the highest autolytic activity in citrate buffer (approximately 48%), was chosen for further investigation of factors influencing the autolysis. These comprised extrinsic factors (incubation temperature) and intrinsic factors (NaCl concentration, pH of the medium, citrate buffer concentration, growth phase). As a reference strain, a non-autolytic strain Lactococcus lactis subsp. lactis NIZO B643 was used. Based on the investigation of the extrisic and intrinsic factors, the most suitable conditions for fast prediction of autolytic activity of a strain were suggested: pre-incubation for 6 h at 30 °C, re-suspendation of cells in 50 mmoll-1 sodium citrate buffer (pH 5.0, containing 15 gl-1 NaCl) and cultivation at 30 °C for 6 days. [ABSTRACT FROM AUTHOR]