Lactic streptococci and the fruity flavor defect of cheddar cheese

The tendency for certain single- and mixed-strain lactic starter cultures to develop a fruity and/or fermented off-flavor in ripening Cheddar cheese was traced to certain strains of Streptococcus lactis in the starter. A very intense fruity and/or fermented flavor developed in experimental cheeses when one particular S. lactis strain was used as a component microorganism in the starter culture. Contrary to previous implications, strains of Streptococcus diacetilactis did not produce a fruity and/or fermented flavor in experimental cheeses made with starter cultures containing these organisms. Mixed-strain cultures of Streptococcus cremoris were used to produce control cheeses, which did not develop the fruity and/or fermented flavor defect. The starter culture and treatment of the cheese milk were the only variables used in the cheesemaking trials. Results obtained indicate that the specific species and/or strain of lactic streptococci contained in the starter culture affect the flavor score and type of flavor in the resultant cheese, independent of the temperature of the heat treatment or hydrogen peroxide-catalase treatment of cheese milk. There were no apparent correlations between "normal" and "defective" starter cultures for the level of proteolytic activity or production of acetaldehyde or diacetyl to the development of fruity and/or fermented off-flavor in cheeses. Existing procedures for the quantification of acetaldehyde, diacetyl and volatile esters were adapted and modified for determining the concentration of these compounds in cheese curd and ripened cheese. The method of slurry preparation, type of diluent and the pH were factors found to affect the recovery rate for acetaldehyde from cheese. The relative flavor preference for typical experimental cheeses was determined with the aid of a flavor panel. A sample of fermented- unclean cheese received the lowest hedonic flavor score, whereas the flavor score of a slight fruity and/or fermented sample compared favorably with that of the reference sample

Subdiffusion of nonlinear waves in quasiperiodic potentials

We study the spatio-temporal evolution of wave packets in one-dimensional quasiperiodic lattices which localize linear waves. Nonlinearity (related to two-body interactions) has destructive effect on localization, as recently observed for interacting atomic condensates [Phys. Rev. Lett. 106, 230403 (2011)]. We extend the analysis of the characteristics of the subdiffusive dynamics to large temporal and spatial scales. Our results for the second moment $m_2$ consistently reveal an asymptotic $m_2 \sim t^{1/3}$ and intermediate $m_2 \sim t^{1/2}$ laws. At variance to purely random systems [Europhys. Lett. 91, 30001 (2010)] the fractal gap structure of the linear wave spectrum strongly favors intermediate self-trapping events. Our findings give a new dimension to the theory of wave packet spreading in localizing environments

Influence of boundary conditions on quantum escape

It has recently been established that quantum statistics can play a crucial role in quantum escape. Here we demonstrate that boundary conditions can be equally important - moreover, in certain cases, may lead to a complete suppression of the escape. Our results are exact and hold for arbitrarily many particles.Comment: 6 pages, 3 figures, 1 tabl

Engineering fidelity echoes in Bose-Hubbard Hamiltonians

We analyze the fidelity decay for a system of interacting bosons described by a Bose-Hubbard Hamiltonian. We find echoes associated with "non-universal" structures that dominate the energy landscape of the perturbation operator. Despite their classical origin, these echoes persist deep into the quantum (perturbative) regime and can be described by an improved random matrix modeling. In the opposite limit of strong perturbations (and high enough energies), classical considerations reveal the importance of self-trapping phenomena in the echo efficiency.Comment: 6 pages, use epl2.cls class, 5 figures Cross reference with nlin, quant-phy

Making American-type cheese at home

Published October 1980. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Making American-type cheese at home

Published June 1975. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Making soft cheeses at home

Published December 1975. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Good farm equipment sanitation means better milk quality tests

Bacteria use milk nutrients that remain on your dairy equipment to grow and multiply between milkings. The most important step in reaching top milk quality is to remove all milk residues (or “soil”) after each milking.Reprinted June 1993. Declared out of print February 2010. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Owning a dairy cow or goat

Discusses how to choose the best type of animal for your needs and briefly mentions issues related to feeding and breeding. Provides information on safely using milk, either fresh or in butter, yogurt, or animal feed.Published September 2010. A more recent revision exists. Please look for up-to-date information in the OSU Extension Catalog: http:/catalog.extension.oregonstate.eduKeywords: Dairy cattle, dairy goat, dairy co

Owning a dairy cow or goat

People living in the suburbs and owning a small acreage often select dairy cattle or dairy goats as a means of harvesting and using their forage. Milk production can reduce the family grocery bill. Goats, especially, will help control brush and weeds and keep the area from becoming unsightly.Published October 2001. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo