Detection and Characterization of Salmonella with Hyperspectral Microscope Imaging ‡ Bosoon Park*, Jaya Sundaram, Arthur Hinton, Jr., Seung-Chul Yoon, William R. Windham and Kurt C. Lawrence 1 U.S. Department of Agriculture, Agricultural Research Service, Athens, GA 30605, USA *Corresponding author. E-mail: bosoon.park@ars.usda.gov Abstract Rapid detection and identification of pathogenic microorganisms naturally occurring during food processing are important in developing intervention and verification strategies. In the food industry, contamination of foodborne pathogens (especially, Salmonella) remains an important public health concern. The development of non-destructive advanced imaging technologies, such as hyperspectral microscope imaging (HMI), for evaluation of foodborne pathogens could enhance the presumptive-positive screening method by reducing labor and increasing detection speed. In this research, we developed optical method to characterize Salmonella serotypes of Enteritidis and Typhimurium. Spectral signatures of Salmonella varied with lighting sources. The spectral peaks from Salmonella were observed at 458, 498, 546, 590, and 670 nm for metal halide lights and at 558, 646, 702, and 772 nm for quartz halogen lights. The experiments demonstrated the potential of HMI for identification of Salmonella using scattering spectral signatures. Key words: Hyperspectral, Acousto-Optical Tunable Filter, Microscopy, Pathogen, Bacteria 1. Introduction In 2011, the Centers for Disease Control and Prevention (CDC) estimated the incidence of foodborne illness about 48 million people in the United States suffer from foodborne illnesses each year, resulting in 128,000 hospitalizations and 3,000 deaths. The cost of foodborne illness in the United States is estimated to be up to $77.7 billion a year (Scharff, 2012) Salmonellosis is an infection with bacteria called Salmonella. Most persons infected with Salmonella develop diarrhea, fever, and abdominal cramps 12 to 72 hours after infection. Every year, approximately 42,000 cases of salmonellosis are reported and Salmonella serotypes Typhimurium and Enteritidis are the most common in the United States. The illness usually lasts 4 to 7 days, and although most persons recover without treatment. However, the Salmonella infection may spread from the intestines to the blood stream, and then can cause death. It is estimated that approximately 400 persons die each year with acute salmonellosis. During past years, several Salmonella outbreaks (Typhimurium and Enteritidis) have been reported for tomatoes in 2006, peanut butter in 2009, shell eggs in 2010, alfalfa, spicy sprouts, and ground beef in 2011, respectively. Most recently, another case of Salmonella (Bareilly or Nchanga) outbreak linked to frozen raw fish commonly used in sushi sicken 316 persons in 26 states (CDC, 2012) Although a conventional microbiological method for cell counting is accurate and still gold standard for foodborne pathogenic bacteria detection, this method is laborious and takes long time from days to weeks for the result. Therefore, very sensitive, accurate and rapid pathogen detection method is needed for a practical use with better performance. Optical ‡ Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.; phone +1 706 546-3396; fax +1 706 546-3607