ABSTRACT
BACKGROUND: The present work is concerned with the probability of contamination by Listeria monocytogenes in the artisanal manufacture of Swiss Emmental hard cheese made from raw milk. The simulation model follows the evolution of the contaminant flora from raw milk at the farm to milk mixing, storage at the cheese factory and to the cheese manufacturing process. METHODS: The simulations are based on models of predictive microbiology, namely the exponential growth model of bacteria including the lag-time, a cardinal growth model and a Log-linear model of thermal deactivation of bacteria. RESULTS: The results of the actual simulation indicate that the contamination of milk at the farm is a rare event (P=0.0036), but the mixing of milk at the cheese factory leads to a higher probability of contamination of cheese milk (P=0.07). Elevated bacterial concentrations are mainly due to cases of mastitis involving Listeria monocytogenes. The decline in bacterial counts during cheese manufacture depends on the curing temperature (52-54 degrees C) and varies between 1.5 and 3.2 Log cfu/ml. Freshly manufactured Emmental-cheese made from contaminated raw milk is expected to have only 4.6 cfu of heat injured Listeria monocytogenes /kg cheese mass in the press. CONCLUSION: Depending on listeria evolution, from the press to the product consumption, consumer exposure has been evaluated and might result in 1 to 10 Listeria monocytogenes per portion of cheese. The bacterial presence could be due to recontamination during packaging, distribution and cheese preparation by the consumer. Based on the presented data and estimations, it is concluded that the consumption of traditionally/artisanal manufactured Swiss Emmental hard cheese presents an extremely low, but existent risk, especially for people with a deficient or diminished immune system.
Subject(s)
Cheese/microbiology , Food Contamination , Food Microbiology , Listeria monocytogenes/isolation & purification , Milk/microbiology , Animals , Humans , Linear Models , Models, Theoretical , Monte Carlo Method , ProbabilityABSTRACT
We addressed the question whether the in vitro interaction of two Epstein-Barr virus (EBV)-genome-positive B cell lines (EB-3 and HilB-gamma) with either Mycoplasma pneumoniae or M. hominis, with the <
Subject(s)
B-Lymphocytes/physiology , Gene Expression Regulation/immunology , Herpesvirus 4, Human/physiology , Interleukins/genetics , Mycoplasma/pathogenicity , B-Lymphocytes/microbiology , B-Lymphocytes/virology , Cell Line, Transformed , Humans , RNA, Messenger/analysis , Receptors, Interleukin-2/geneticsABSTRACT
Chromopeptide siderophores (azotobactin 87-I and -II) were isolated from an iron deficient culture medium of Azotobacter vinelandii ATCC 12837 (= DSM 87). Their structures were elucidated by chemical degradation studies and spectroscopic methods, especially 2D-NMR-techniques. Total assignments of 1H-, 13C-, and 15N-resonances based on 2D-HOHAHA-, 1H/13C-HMQC-, 1H/13C-HMBC-, 1H/15N-HMQC/TOCSY-, and 1H/15N-HMBC-experiments are given as well as sequential information derived from 1H/1H-NOESY-, 1H/13C-HMBC- and 1H/15N-HMBC-experiments. Both Az 87-I and Az 87-II consist of a tetracyclic chromophore-- (1S)8,9-dihydroxy-4-oxo-2,3,4,5-tetrahydro-1H,10cH-3a,5,10b- triazaacephenantrylene-1-carboxylic acid--and a decapeptide chain linked with the N-terminus to the carboxy group of the chromophore containing also modified, non-proteinogenic amino acids. The sequence L-Ser-D-Ser-L-Hse-Gly-D-threo-OHAsp-Hse-Hse-Hse-D-N5OH-N5-R- Hbu-Orn-L-Hse was determined for Az 87-I, while Az 87-II contains a C-terminal L-Hse-lactone instead. Iron is chelated by the catecholic group of the chromophore, the beta-hydroxy aspartic acid, and the hydroxamate function formed by N5-hydroxyornithine and R-beta-hydroxybutyric acid.
Subject(s)
Azotobacter vinelandii/metabolism , Peptides/chemistry , Amino Acid Sequence , Chromatography, High Pressure Liquid , Gas Chromatography-Mass Spectrometry , Magnetic Resonance Spectroscopy , Models, Structural , Molecular Sequence Data , Peptide Biosynthesis , Peptide Fragments/chemistry , Peptide Fragments/isolation & purification , Peptides/isolation & purification , Siderophores , Spectrometry, Mass, Fast Atom BombardmentABSTRACT
An outpatient educational system for diabetics has been employed in Delémont since 1984 in the form of a 4-day course consisting of a total of 15 teaching hours. This teaching method has been evaluated in the first 51 patients. The level of information (tested by a series of multiple choice questions which are submitted to the patients at the beginning, at the end of the course and three months later) was found to improve. The score (0-17) rose from 6.6 to 11.9 and then 12.5; n = 35; p less than 0.001. The HbA1c fell significantly in a three month period from 8.8 to 7.8%, n = 12, p less than 0.02. The slight lowering of average fasting serum glucose levels (from 10.4 to 9.7 mmol/l) and of the patients' weights (from 75.4 to 74.6 kgs) was not significant. - The advantage of the educational system that has been studied is its low cost and the fact that it is accepted well by patients.