Identification and Enumeration of Salmonella on Sample Slides of Poultry Carcasswashwater Using Image Analysis With Fluorescent Microscopy

Rapid detection of bacteria on poultry carcasses is desirable for the poultry industry to enhance food safety ofpoultry products. This research focused on image analysis with fluorescent microscopy for identification and enumeration ofSalmonella typhimurium on sample slides of poultry carcass wash water which were prepared using fluorescent antibodiesand immuno-magnetic beads. The criteria of morphological and optical characteristics of S. typhimurium cells, includingarea, 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, imagedilation and erosion, image flattening, and watershed filtering was selected using Image-Pro Plus software to analyze theacquired images. The algorithm was trained with 110 slide samples. The regression analysis showed that the relationshipbetween the automatic image counting and the microbial plate counting was linear with a correlation coefficient of 0.88. Thedetection limit of this method was 1 104 cells/mL, and the time needed was less than 4 h.