The resistance to detachment of dairy strains of Listeria monocytogenes from stainless steel by shear stress is related to the fluid dynamic characteristics of the location of isolation.
Strains of Listeria monocytogenes isolated from artisanal Portuguese cheese-making dairies were divided into two categories on the basis of the locations from which they were isolated: strains from dynamic locations were those that were habitually exposed to flowing liquids during the process of cheese-making, whereas those from static locations were rarely, if ever, exposed to the shear stresses generated by liquid flows. The strength of attachment to stainless steel discs of all of these strains was obtained using a radial flow chamber. Initial attachment strengths to stainless steel (after a 0.5 h contact time) of L. monocytogenes strains were greater for the 5 isolates from surfaces exposed to flow (dynamic isolates) than for most (3 out of 4) of those that were not (static isolates). After a 24 h contact time, attachment strength of all isolates reached similar levels. These results suggest that strains having high initial attachment strength are more likely to persist on surfaces exposed to flow than strains having low initial attachment strength. The numerical values of shear forces obtained could prove useful in the rational design of cleaning and decontamination procedures in food processing facilities.
Perni
Stefano
S
Department of Chemical Engineering, University of Loughborough, Loughborough, LE11 3TU, UK.
Aldsworth
Timothy G
TG
Jordan
Suzanne J
SJ
Fernandes
Isabel
I
Barbosa
Manuela
M
Sol
Manuela
M
Tenreiro
Rogério P
RP
Chambel
Lélia
L
Zilhão
Isabel
I
Barata
Belarmino
B
Adrião
Andrea
A
Leonor Faleiro
M
M
Andrew
Peter W
PW
Shama
Gilbert
G
D001422:Bacterial Adhesion / Q000502:physiology*; D002611:Cheese / Q000382:microbiology*; D015169:Colony Count, Microbial; D004783:Environmental Microbiology; D004866:Equipment Contamination; D005516:Food Microbiology; D005525:Food-Processing Industry / Q000592:standards*; D007700:Kinetics; D008089:Listeria monocytogenes / Q000502:physiology*; D013193:Stainless Steel
D013193:Stainless Steel