Inhibition of spoilage yeasts in cheese by killer yeast Williopsis saturnus var. saturnus.
Williopsis saturnus var. saturnus is a known killer toxin-producing yeast. The effects of this yeast as a biopreservative against spoilage yeasts (galactose fermenting) were investigated in cheeses made under laboratory conditions. At an inoculation level of approximately 10(6) CFU/g of cheese, this killer yeast inhibited growth of lactose non-fermenting but galactose-fermenting yeast Saccharomyces cerevisiae VL1 inoculated at approximately 10(3) CFU/g; it also inhibited growth of lactose-fermenting and galactose-fermenting yeast Kluvyveromyces marxianus ATCC8640 inoculated at approximately 10(3)-10(4) CFU/g in the cheeses manufactured with galactose-producing starter culture Streptococcus thermophilus. In contrast, the two spoilage yeasts grew to approximately 10(6) CFU/g from the initial cell count of approximately 10(3) CFU/g without the killer yeast. This study indicated that W. saturnus var. saturnus could be an effective biopreservative for cheese spoilage control.
Liu
Shao-Quan
SQ
Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Singapore. chmLsq@nus.edu.sg
Tsao
Marlene
M
D002611:Cheese / Q000382:microbiology*; D015169:Colony Count, Microbial; D005285:Fermentation; D005690:Galactose / Q000378:metabolism; D055646:Killer Factors, Yeast / Q000494:pharmacology*; D007716:Kluyveromyces / Q000187:drug effects* / Q000254:growth & development; D007785:Lactose / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000254:growth & development; D013291:Streptococcus / Q000187:drug effects / Q000254:growth & development; D055320:Williopsis
D055646:Killer Factors, Yeast; D007785:Lactose; D005690:Galactose