A simple procedure for determining the presence and concentration of Listeria monocytogenes in dairy products.
This paper presents a simple method for determining both the presence and concentration of Listeria monocytogenes in dairy products. The method involves application of the Most Probable Number (MPN) technique and enrichment of a 25 g sample. Our tests showed that the MPN correlates with the Colony Forming Units (CFU), and estimated concentrations of as low as 1 bacterium/gr or less. We also studied the influence of Listeria innocua as an accompanying flora. We detected L. monocytogenes, even in the presence of concentrations of 4 times as much L. innocua. Nonetheless, L. monocytogenes could not be detected when the concentration of L. innocua surpassed 90%.
School of Pharmacy and Biochemistry, University of Buenos Aires, Argentina.
S A
SA
Teves
A M
AM
Bravo
J
J
Degrossi
M
M
Franco
M
M
D'aquino
D000818:Animals; D001431:Bacteriological Techniques; D002417:Cattle; D003470:Culture Media; D003611:Dairy Products / Q000382:microbiology*; D005285:Fermentation; D005506:Food Contamination; D005516:Food Microbiology; D008089:Listeria monocytogenes / Q000302:isolation & purification*; D008403:Mass Screening; D008892:Milk / Q000382:microbiology
D003470:Culture Media