Separation of Listeria monocytogenes and Salmonella berta from a complex food matrix by aqueous polymer two-phase partitioning.
In the present study, the use of aqueous polymer two-phase systems for separation of pathogenic bacteria from a complex food sample was investigated. Three different two-phase systems, a polyethylene glycol 3350/dextran T 500, a methoxy polyethylene glycol 5000/dextran T 500 and a polyethylene glycol 3350/hydroxypropyl starch system, were compared at pH 3 and pH 6 for their capacity to separate the pathogenic bacteria Listeria monocytogenes and Salmonella berta from a Cumberland sausage. In all three phase systems, the food particles partitioned to the lower phase. Best performance was obtained by the polymer combinations, polyethylene glycol 3350/dextran T 500 and polyethylene glycol 3350/hydroxypropyl starch. In these systems, Salmonella berta partitioned to the hydrophobic upper phase both at pH 3 and pH 6 with an average partitioning ratio of 80% and a recovery of 56%. Listeria monocytogenes partitioned to the upper phase at pH 3 only with an average partitioning ratio of 72% and a recovery of 45%. This method may become a valuable tool for separation of bacteria from complex food matrices.
Pedersen
L H
LH
Biotechnological Institute, Hørsholm, Denmark. lap@bio.atv.dk
Skouboe
P
P
Rossen
L
L
Rasmussen
O F
OF
D001431:Bacteriological Techniques; D003911:Dextrans; D008089:Listeria monocytogenes / Q000302:isolation & purification*; D008461:Meat Products / Q000382:microbiology*; D008722:Methods; D011092:Polyethylene Glycols; D011108:Polymers; D012475:Salmonella / Q000302:isolation & purification*; D013213:Starch / Q000031:analogs & derivatives
D003911:Dextrans; D011108:Polymers; D011092:Polyethylene Glycols; D013213:Starch