Evaluation of Aroma Generation of Lactococcus lactis with an Electronic Nose and Sensory Analysis

Agarose gel electrophoresis of PCR products formed by acmA gene amplification showing the specificity of primers PALA-4 and PALA-14. Lane 1=100-bp DNA ladder; lane 2=Escherichia coli O157:H7 ATCC 43888; lane 3=Staphylococcus aureus ATCC6538; lane 4=Lactococcus strain 21; lane 5=Listeria monocytogenes ATCC 7644; lane 6=Salmonella typhimurium ATCC 14028.

Agarose gel electrophoresis of PCR products formed by acmA gene amplification, with primers PALA-4 and PALA-14 for the identification of Lactococcus lactis. Lane 1=100-bp DNA ladder; lane 2=strain 22; lane 3=strain 5; lane 4=strain 20; lane 5=strain 23; lane 6=strain 11; lane 7=strain 1; lane 8=Lactobacillus acidophilus 742VD; lane 9=Lactobacillus casei 163VD.

Growth curves of the different strains of Lactococcus lactis in UHT milk at 30°C isolated from dairy products ●, nondairy products ▿, and commercial dairy starter cultures ◊.

Principal component analysis based on electronic nose data produced by milk inoculated with different strains of Lactococcus lactis isolated from dairy products ●, nondairy products ▿, and commercial dairy starter cultures ◊. Numbers correspond to strain codes in Table 1.

Mean odor intensity scores of milk inoculated with 23 strains of Lactococcus lactis isolated from dairy products, nondairy sources, and commercial dairy starter cultures. Numbers correspond to strain codes in Table 1. ^a–fBars with different letters were significantly different (P<0.05) after the Tukey multiple comparison test.