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.
Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Singapore. chmLsq@nus.edu.sg
Shao-Quan
SQ
Liu
Marlene
M
Tsao
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