IDENTIFICATION AND ENUMERATION OF SALMONELLA ON SAMPLE SLIDES OF POULTRY CARCASSWASHWATER USING IMAGE ANALYSIS WITH FLUORESCENT MICROSCOPY

Abstract

Rapid detection of bacteria on poultry carcasses is desirable for the poultry industry to enhance food safety of poultry products. This research focused on image analysis with fluorescent microscopy for identification and enumeration of Salmonella typhimurium on sample slides of poultry carcass wash water which were prepared using fluorescent antibodies and immuno-magnetic beads. The criteria of morphological and optical characteristics of S. typhimurium cells, including area, aspect ratio, diameter, major and minor axis, maximum and minimum radii, perimeter, radius ratio, length and width, and intensity, were developed. An algorithm that included channel extracting, median filtering, image sharpening, image dilation and erosion, image flattening, and watershed filtering was selected using Image-Pro® Plus software to analyze the acquired images. The algorithm was trained with 110 slide samples. The regression analysis showed that the relationship between the automatic image counting and the microbial plate counting was linear with a correlation coefficient of 0.88. The detection limit of this method was 1 ×104 cells/mL, and the time needed was less than 4 h.