For experimental contamination of the RTE meat products, the
strains were grown overnight separately in BHI at 37 C, transferred
to fresh BHI and incubated at 37 C for 10 h, correspondent to early
stationary phase, as indicated by a standard growth curve. Equal
volumes of each culture were mixed and centrifuged at 6000 g
for 10 min under refrigeration. The supernatants were discarded
and the pellets re-suspended in sterile 0.1% PW. The procedure was
repeated three times. The last pellets were re-suspended in sterile
0.1% PW until a suspension with OD595 ¼ 0.5 (Ultrospec 2000;
Pharmacia, USA) (108 CFU mL1) was obtained.