ABSTRACT
A multilaboratory study was conducted to compare the automated BAX system and the standard cultural methods for detection of Listeria monocytogenes in foods. Six food types (frankfurters, soft cheese, smoked salmon, raw, ground beef, fresh radishes, and frozen peas) were analyzed by each method. For each food type, 3 inoculation levels were tested: high (average of 2 CFU/g), low (average of 0.2 CFU/g) and uninoculated controls. A total of 25 laboratories representing government and industry participated. Of the 2335 samples analyzed, 1109 were positive by the BAX system and 1115 were positive by the standard method. A Chi square analysis of each of the 6 food types, at the 3 inoculation levels tested, was performed. For all foods, except radishes, the BAX system performed as well as or better than the standard reference methods based on the Chi square results.
Subject(s)
Food Microbiology , Listeria monocytogenes/isolation & purification , Polymerase Chain Reaction/methods , Chi-Square DistributionABSTRACT
A reagent strip has been developed for measuring phenobarbital concentrations in serum or plasma. This strip utilizes the apoenzyme reactivation immunoassay system (ARIS) and is designed for use with the Ames Seralyzer reflectance photometer. The test takes 85 s and compares strip reactivities with a two-point calibration line that is stored in the instrument. Within-run precision coefficient of variation ranges from 2.4 to 4.1% over five concentrations while the between-run precision ranges from 2.3 to 4.9%. Results obtained with clinical serum samples correlated well (r greater than 0.99) with those obtained by a fluorescence polarization immunoassay (TDx). The strips crossreact with other barbituric acid derivatives that are not coadministered with phenobarbital. Crossreactivity to the metabolite p-hydroxyphenobarbital is sufficiently low as to not interfere in the usual specimens. Samples that are hemolyzed, highly icteric, or from uremic patients should be avoided. This assay is a rapid and convenient method for monitoring serum or plasma phenobarbital concentrations. It is particularly well suited for decentralized test sites, such as emergency rooms, urgent care centers, and physician's offices.
