(306f) Hollow Fiber Microfiltration Principles Impacting Pathogen Recovery to Enable Rapid Detection

Existing enrichment methods used for food pathogen detection often require >24 hours to produce detectable pathogen levels. There is increasing demand for methods which more quickly (<8 hours) isolate and detect pathogens from food or water samples. Previously, several continuous cell concentration devices were prototyped using hollow fiber microfilter modules. Using these prototypes, low levels of bacterial pathogens were rapidly concentrated (within 8 hours) from poultry, egg, and spinach samples. Effective use of microfiltration for cell concentration reduces the sample volume while releasing the microorganism of interest in the retentate. Improved bacterial recovery from the filter translates to greater CFU concentrations in the eluate – this permits pathogen detection at lower initial concentrations. Here, flow on both the feed and permeate sides of the filter membrane was modulated using two pumps (dual flow), and flow rates and pressures of the hollow fiber module feed, retentate, and permeate were monitored. Flow modulation directly affects the linear velocity, transmembrane pressure, and surface flow in the filter. These operational parameters affected the recovery of bacteria from a sample. When using a back-flushing process, for instance, recovery greatly improved in buffered peptone water samples – 36% versus <1% without back-flushing. In this work, the impacts of linear velocity, surface flow, transmembrane pressure (flux), and back-flushing on the recovery of bacterial pathogens are discussed. Improved bacterial recovery from the microfiltration process would improve the limit of pathogen detection across various sample types while maintaining a rapid concentration process.