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Identification and Sub-typing of Food-born Bacteria From Animal Feed Ingredients, Animal Feed & Pet Foods Samples Using Matrix-assisted Laser Desorption & Ionization Time-of-flight Mass Spectrometry.

Zhang, Yan
Colorado State Department of Agriculture
Start date
End date
FDA CVM VET-LRN PROGRAM (U18) GRANT PROPOSAL FOR FOA # PA-13-244, CFDA 93, 103Project Summary/AbstractThis project will use Matrix-Assisted Laser Desorption Ionization Time-of-Flight massspectrometry (MALDI-TOF MS) for identification of human foodborne pathogens, includingSalmonella, E. coli, Campylobacter species, Listeria monocytogenes, Clostridium perfringens,and Staphylococcus aureus in animal feed ingredients, pet foods and animal feed. The first yearof the project will focus on identification and subtyping of Salmonella bacteria using MALDI-TOF MS. The same approach will be used for other foodborne pathogens in the following fouryears. Salmonella contamination of pet foods/animal feeds has resulted in outbreaks of humanSalmonellosis. However, contamination of animal feed ingredients, animal feed, and pet treatsand foods have not been systematically studied. Routine culture is the 'gold standard' methodfor isolation and identification. This method is labor intensive, expensive, and time consuming,which does not provide timely information before the distribution of the contaminated animalfood matrices. Therefore, alternative methods for rapid and reliable identification and subtypingof Salmonella bacteria are urgently needed to improve safety and integrity of animal feed supply,which in turn will limit human infections. In this application we propose to develop methodsusing MALDI-TOF MS for rapid and specific identification and typing of Salmonella bacteriagrown on preliminary culture plates from animal feed matrices. Microbial identification usingthis technology is based on the comparison of spectral patterns obtained directly from cells orcell extracts against reference spectra using a pattern recognition algorithm. This technology iscurrently available in the form of commercial platforms, and a considerable amount of studieshave been generated demonstrating its utility for identification and typing of Salmonella bacteria.We have successfully used this technology for identification of Salmonella bacteria in fecal andanimal tissue samples. There is, however, a lack of knowledge regarding the use of MALDI-TOFMS for identification of bacterial isolates from pet food and animal feed matrices. The proposedstudy will address these issues by the following three specific aims:Specific aim 1: Identification and subtyping of foodborne bacterial isolates from various animalfood matrices using MALDI-TOF MS using a novel library.Specific aim 2: Identification and subtyping of foodborne bacteria directly from colonies grownon various culture media from animal feed and food matrices.Specific aim 3: Transferring and training of this new methodology to other Vet-LIRNlaboratories.Successful completion of this project will expand the current application of this technology fromfecal and animal tissue samples to animal feed matrices to improve the safety and integrity of theUS animal feed supply. In addition, the multi-laboratory collaboration validation of thismethodology will increase Vet-LIRN laboratory capability and capacity in order to serve CVM'sneed for rapid turnaround times when responding to animal food contamination events.
Funding Source
Food and Drug Administration
Project source
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Project number
Bacterial Pathogens