title: Enzymatic Digestion for Improved Bacteria Separation from Leafy Green Vegetables.
abstract: An effective and rapid method for the separation of bacteria from food matrix remains a bottleneck for rapid bacteria detection for food safety. Bacteria can strongly attach to a food surface or internalize within the matrix, making their isolation extremely difficult. Traditional methods of separating bacteria from food routinely involve stomaching, blending, and shaking. However, these methods may not be efficient at removing all the bacteria from complex matrices. Here, we investigate the benefits of using enzyme digestion followed by immunomagnetic separation to isolate Salmonella from spinach and lettuce. Enzymatic digestion using pectinase and cellulase was able to break down the structure of the leafy green vegetables, resulting in the detachment and release of Salmonella from the leaves. Immunomagnetic separation of Salmonella from the liquefied sample allowed an additional separation step to achieve a more pure sample without leaf debris that may benefit additional downstream applications. We have investigated the optimal combination of pectinase and cellulase for the digestion of spinach and lettuce to improve sample detection yields. The concentrations of enzymes used to digest the leaves were confirmed to have no significant effect on the viability of the inoculated Salmonella. Results reported that the recovery of the Salmonella from the produce after enzyme digestion of the leaves was significantly higher (P < 0.05) than traditional sample preparation methods to separate bacteria (stomaching and manually shaking). The results demonstrate the potential for use of enzyme digestion prior to separation can improve the efficiency of bacteria separation and increase the likelihood of detecting pathogens in the final detection assay.
authors: Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors: Danhui
authors: D
authors: Wang
authors: Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors: Ziyuan
authors: Z
authors: Wang
authors: Department of Food Science and Technology, Oregon State University, Corvallis, Oregon 97331, USA.
authors: Fei
authors: F
authors: He
authors: Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors: Amanda J
authors: AJ
authors: Kinchla
authors: Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, USA; Department of Food Science, Cornell University, Ithaca, New York 14853, USA. snugen@cornell.edu.
authors: Sam R
authors: SR
authors: Nugen
mesh_terms: D001419:Bacteria; D015169:Colony Count, Microbial; D005506:Food Contamination; D005516:Food Microbiology; D018189:Immunomagnetic Separation; D018545:Lactuca / Q000382:microbiology; D014675:Vegetables / Q000382:microbiology*