Enumeration of L. monocytogenes was carried out according to
the method described by EVS-EN ISO 11290-2:2000/A1:2004. In all
cases enumeration was performed at the use-by-date. For making
initial suspensions and dilutions (101 to 103
) buffered peptone
water (ISO, Oxoid) was used. The procedure included 1-h resuscitation
in buffered peptone water at room temperature, and surface
plating on ALOA agar of 1.0 ml of 101
, and 0.1 ml of each of the 102
and 103 dilutions to duplicates of the ALOA plates. The plates were
incubated at 37 C for 24e48 h. Typical colonies were selected and
plated on 5% sheep blood agar. L. monocytogenes was confirmed as
described above.
2.3