ABSTRACT
In order to protect farm animals from infections such as foot and mouth disease (FMD) and tuberculosis, the pasteurisation of milk and milk products designated for the feeding of animals is compulsory in Switzerland. Nowadays, milk products are often treated chemically with acids or with hydrogen peroxide in order to keep bacterial contamination low. The capacity of these chemical treatments to inactivate FMD virus in skimmed milk within 6 h at 5 degrees C was tested in this study. The results indicated that the addition of 0.1%-0.3% of consumable acids, such as citric acid or propionic acid, could not guarantee the complete inactivation of FMD virus in skimmed milk. Similar results were obtained both with FMD virus deliberately added to skimmed milk and with skimmed milk obtained from naturally infected cows. Hydrogen peroxide in concentrations of 0.1%-0.3% was also an ineffective means of controlling the risk of FMD virus transmission from contaminated milk.
Subject(s)
Aphthovirus/drug effects , Citrates/pharmacology , Hydrogen Peroxide/pharmacology , Milk/microbiology , Propionates/pharmacology , Animals , Cattle , Cattle Diseases/microbiology , Citric Acid , Female , Foot-and-Mouth Disease/microbiology , Hydrogen-Ion Concentration , KineticsSubject(s)
Body Height , Femur/anatomy & histology , Fossils , Humerus/anatomy & histology , Paleontology , Tibia/anatomy & histology , Anthropometry/methods , Germany , History, 15th Century , History, 16th Century , History, 17th Century , History, 18th Century , History, 19th Century , History, Medieval , Humans , MaleABSTRACT
A high frequency modulation method utilizing a photoelastic polarization modulator for the measurement of optical birefringence is described and discussed. Although the apparatus has the high sensitivity required to measure very small retardations, the accurate measurement of larger retardations is emphasized and a particularly simple null detection technique for such measurements is described. Results obtained for some common uniaxial crystals are presented and compared with previously obtained results.
