A method for the assessment of volatile compounds in dairy products
was developed using solvent desorption dynamic headspace sampling. The
method was first applied to assay for diacetyl and acetoin in buttermilk.
Major buttermilk volatiles recovered included diacetyl, acetic acid, and
acetoin. Normalized detector responses were linear over the range...
Heat resistant sporeforming psychrotrophic bacteria were
isolated from raw milk samples from 59 Grade A farms in Oregon.
Forty-nine of the 59 (83%) raw milk samples in this survey
contained sporeforming psychrotrophic bacteria; isolates from
twenty-four (40%) of the samples exhibited proteolytic properties. Populations of sporeforming psychrotrophic bacteria ranged
from...
A casein agar diffusion method was developed to detect and quantify pertinent
levels of proteinases produced in raw milk supplies by heat resistant Bacillus
sporeformers. In order to optimize the required heat treatment conditions of raw milk
samples, trials that involved a combination of different temperatures and times were
evaluated....
Several methods for estimation of the potential
shelf-life of pasteurized fluid milk products were evaluated
for their efficacy in this investigation. These methods
were evaluated and compared to sensory, biochemical and
bacteriological indices through a series of experiments
conducted on different brands of commercially pasteurized
fluid milk. The methods evaluated...
Phage-insensitive Streptococcus cremoris starter strains were
selected by assaying cheese whey against potential starter
strains. Six strains were selected and characterized for continual
use in cheesemaking. Upon phage-infection, strains were removed
from the blend. Cheesemaking continued with remaining strains. A
phage-insensitive, fast-acid-producing mutant of the infected
strain was isolated and...
The effect of reducing sodium chloride in Cheddar cheese was
studied. Milled curd from a split-lot was salted at selected NaCl
concentrations and analyzed through aging by sensory and rheological
tests. Estimation of differences in compositional analysis, lactic
acid populations, degree of proteolysis, water activity, and pH were
also determined....
A consumer and a trained descriptive panel was utilized to
determine liking ratings and flavor profiles, respectively, for
commercial brands of pre-stirred yogurt. Once the consumer and
descriptive panel data was collected, the data was combined to
determine the interrelationship of these two sets of data and to
determine the...
Microgard, a commercially-available pasteurized
fermented milk, was found inhibitory to gram negative
bacteria such as Pseudomonas putida, some well-known foodborne
pathogens (e.g. Salmonella, Yersinia and Aeromonas)
and some fungi as revealed by an agar incorporation assay
method. Gram positive bacteria, however, were not
inhibited. Rather, some bacteria in this group...