Rapid radiometric method for detection of Salmonella in foods

Abstract

A radiometric method for the detection of Salmonella in foods has been developed which is based on Salmonella poly H agglutinating serum preventing Salmonella from producing 14CO2 from [14C]dulcitol. The method will detect the presence or absence of Salmonella in a product within 30 h compared to 4 to 5 days by routine culture methods. The method has been evaluated against a routine culture method using 58 samples of food. The overall agreement was 91%. Five samples negative for Salmonella by the routine method were positive by the radiometric method. These may have been false positives. However, the routine method may have failed to detect Salmonella due to the presence of large numbers of lactose-fermenting bacteria which hindered isolation of Salmonella colonies on the selective agar plates.

Some modification to the media for rapid automated detection of salmonellas by conductance measurement

“…Dulcitol fermentation is a property of subgenus I salmonellas but is a variable or absent property in the other subgroups (Le Minor 1981, 1984Parker 1983). Stewart et al (1980) calculated from their data that only one salmonella in 7000 isolated from foods should be dulcitolnegative. Such a low proportion would mean that in view of the statistical probability of sampling there would be an insignificant number of false negatives.…”

Application of flow cytometry to rapid microbial analysis in food and drinks industries

“…Indirect methods are based either on the measurement of the products of cell metabolism or on the quantification of change of chemical properties of the culture medium induced by microorganisms growth. ATP assay [19], radioimmunoassay (RIA) [7], enzyme-linked immuno-* Correspondence and reprints absorbent assay (ELISA) [23], microcalorimetry [11], electrical impedance [5] and radiometry [20] belong to this group.…”

Rapid Detection of Salmonella spp. by Using Felix-O1 Bacteriophage and High-Performance Liquid Chromatography

“…However, unless carefully prepared, non-crossreacting reagents are used, an unacceptably high incidence of false-positive reactions is observed (1,10,15,17,20,21,23,24). On the other hand, methods that utilize growth or metabolic characteristics of a particular microorganism need additional time for the desired traits to be expressed (18,22). Some methods are designed for the identification of characteristic substances elaborated by a particular microorganism (6,13,14,16).…”