Immunoassays, such as enzyme-linked immunosorbent assays
(ELISA), have been developed for rapid detection of L. monocytogenes.
These methods target antibodies specific to Listeria, and
although less time-consuming than classical culturing, they are
less sensitive with detection limits of 104
–106 CFUml1 [20].
Detection of L. monocytogenes in artificially contaminated milk
samples using MALDI-TOF MS was recently reported [21].
Here, two enrichment steps were required and detection of
L. monocytogenes in milk spiked with an initial inoculum of
1 CFUml1 was possible after 30 h. The detection of VOCs liberated
from enzyme substrates could potentially be used as a rapid
method for the detection of L. monocytogenes. However, currently
the method has several limitations; these include use of a small
sample size and a limited range of reference bacteria. Testing the
method with a larger sample size, in addition to examining the
VOCs generated by other strains of all Listeria species would
be necessary. In addition, samples used to test the method were
artificially contaminated; further investigations would be required
using real-life samples