Presenter: Niharika Mishra
Authors: Niharika Mishra, Michele Culumber, Craig Oberg
Faculty Advisor: Michele Culumber
Institution: Weber State University
Paucilactobacillus wasatchensisis afastidious organismthat utilizes ribose sugar and liberates carbon dioxide with six carbon sugars such asgalactose. This organism is one of the causesof late gas defect in cheddar cheese.Over-production of gasses disrupts the flavor and texture of the cheese.This organism is a contaminant in the cheese industry but wedo notknow its environmental sources.Related organisms have been isolated from silage and compost.We hypothesize thatP. wasatchensisresides inenvironmental samples around the dairy cows and contaminates the milk during milking.Samples of corn silage, hay silage, pre-compost, post compost, and sugar beetrootwere collectedfrom Utah State University dairy farm.Samples werehomogenized, diluted,and plated on agar(MRS+1% ribose and MRS+1% ribose + Vancomycin).Colonieswere markedon the plate after two days incubation at25°Candthe plates wereincubated for seven more days.Unmarked colonieswere selected andincubated inbroth(MRS+Ribose(0.3%) + galactose (0.7%)) with a Durham tubefor 72 hoursto identify gas-producingisolates.Weconducted16S rRNA gene sequencingandanalyzedthe sequencesusing theBLASTagainst the NCBI data base.P. wasatchensishas not been found in the samples. However,isolatePCRV2 was94.98%similar.PCRV2 was isolated from pre-compost samples.API50CHpanelsof PCRV2indicate the organism is notP.wasatchensis, but it could be a related organism.Weare working oncollecting moreisolatesfrom the pre-compost andsilagesamples. Analysis of DNA extracted directly for the environmental samples will also be done to help identify the sources ofP. wasatchensis.