Accelerating sample preparation through enzyme‐assisted microfiltration of Salmonella in chicken extract

Abstract

Microfiltration of chicken extracts has the potential to significantly decrease the time required to detect Salmonella, as long as the extract can be efficiently filtered and the pathogenic microorganisms kept in a viable state during this process. We present conditions that enable microfiltration by adding endopeptidase from Bacillus amyloliquefaciens to chicken extracts or chicken rinse, prior to microfiltration with fluid flow on both retentate and permeate sides of 0.2 μm cutoff polysulfone and polyethersulfone hollow fiber membranes. After treatment with this protease, the distribution of micron, submicron, and nanometer particles in chicken extracts changes so that the size of the remaining particles corresponds to 0.4-1 μm. Together with alteration of dissolved proteins, this change helps to explain how membrane fouling might be minimized because the potential foulants are significantly smaller or larger than the membrane pore size. At the same time, we found that the presence of protein protects Salmonella from protease action, thus maintaining cell viability. Concentration and recovery of 1-10 CFU Salmonella/mL from 400 mL chicken rinse is possible in less than 4 h, with the microfiltration step requiring less than 25 min at fluxes of 0.028-0.32 mL/cm(2) min. The entire procedure-from sample processing to detection by polymerase chain reaction-is completed in 8 h.

Human pathogens in plant biofilms: Formation, physiology, and detection

“…We have developed an accelerated sample preparation methodology in our laboratory for meat and egg products, that combines short enrichment of microorganisms with enzyme hydrolysis followed by hollow‐fiber microfiltration and PCR for rapid detection of target human pathogens (Ku et al, ,; Li et al, ; Vibbert et al, ). This approach has the potential to be used as a toll for reducing the time required for sample separation and concentration from the current 24–48 h to a time scale of 1–2 h, allowing more time effective generation of results.…”

Recent and emerging innovations inSalmonelladetection: a food and environmental perspective

“…blended or stomached) samples. While this approach has been widely used to test large volumes of water, the testing of food samples was problematic due to clogging of filter membranes by large food particles (Li et al ., ; Vibbert et al ., ). To overcome this problem, endopeptidases have been added to the stomached food samples.…”

“…To overcome this problem, endopeptidases have been added to the stomached food samples. These degrade the small, soluble proteins and peptides so that they are unable to clog the filter and pass through with the permeate (Vibbert et al ., ). Additional filtration advances include the use of hollow‐fibre filter membrane cartridges, which have higher surface‐to‐volume ratios than flat‐sheet membranes, as well as cross‐flow, or tangential flow, where the sample flows across the membranes to further aid in the reduction of membrane fouling (Cho et al ., ).…”

Current and Emerging Innovations for Detection of Food-Borne Salmonella

“…The enrichment steps mainly rely on iltering liquids, rinsates, or mechanically disintegrated (i.e., blended or stomached) samples. Therefore, this approach has been widely used in large volumes of water, but the testing of food samples was problematic due to the food particles diicult to go through ilter membranes [71]. To overcome this problem, endopeptidases have been added to apply in food samples.…”