Development of rapid methods for determination of Salmonella in meat products

The aim of the present study was the evaluation of two different techniques to detect Salmonella in meat: an ELISA assay using electrochemical detection coupled with a FIA system and a PCR method. A sandwich format was chosen for ELISA assay, using monoclonal and polyclonal antibodies against salmonella. A 35-cycle PCR was carried out for the research of genomic fragment. The assays were used to analyse samples of pork, chicken and bovine meat experimentally contaminated with different concentrations of S. Enteritidis. Results show that both methods were efficient, sensitive and rapid. After only 4 hours of incubation in pre-enrichment broth (buffered peptone water) it was possible to detect salmonella in meat experimentally contaminated with low concentrations (1-10 cells in 25 g) both with the ELISA assay and the PCR method

CYCLIC ENZYMATIC DETERMINATION OF L-LACTATE BY DIFFERENTIAL PH MEASUREMENT

An electrochemical procedure for the analysis of L-lactate based on the lactate dehydrogenase/lactate oxidase reaction cycle has been developed and applied in whole blood and wine. The reaction of lactate with lactate oxidase produces pyruvate, which is the substrate, at physiological pH, of the enzyme lactate dehydrogenase. This enzyme, in the presence of NADH, converts pyruvate to lactate consuming H+ An automated software controlled differential pHmeter was used for H+ detection and the Delta pH measured was correlated to the lactate concentration present in the sample. Lactate was measured in the range 0.4-20 mmol/L with a detection limit of 0.2 mmol/L. Recovery studies have been carried out to evaluate the effect of blood and wine matrices on lactate determination. The recovery was between 94 and 104% in blood and 93 and 104% in wine. Analysis of lactate in blood and wine samples has been carried out. Comparison with a reference spectrophotometric procedure has been reported and discussed.[...