Moving Forward to Achieve
Global Listeria Control
Listeria monocytogenes is like an opponent you think you have punched out but keeps coming back for more. The food industry and government have long been aware of the persistence of Listeria in the environment and in processing plants, and they have introduced many poli-
cies and procedures to limit the contamination and
growth of the pathogen. However, every few years there
seems to be a
major out-
break, often
with high mor-
tality, which
catches indus-
try, govern-
ment and the
public un-
aware and
causes great
angst. Cases
appear to be rising, and recent trends in North America
and Europe seem to show the growing elderly population
most at risk. Other reasons given for the possible in-
crease, apart from better surveillance and detection
methodologies, are increased consumption of ready-to-eat
(RTE) foods; increased storage time and temperature of
RTE foods leading to growth of the pathogen; increased
virulence of Listeria strains; and more
persons at risk of infection. There are
now cases documented in developing countries where listeriosis was
not considered an issue previously.
Global Listeria Control
All these examples point to the
need for better strategies for prevention and control of the pathogen
worldwide. The Codex Alimentarius
Commission (CAC), through its
Committee on Food Hygiene
(CCFH), has been looking at a standard that is universally accepted, because many of the implicated
products are, in international trade,
soft cheeses, delicatessen meats and
smoked fish. The CCFH agreed that
five key factors that contribute
strongly to the risk of listeriosis associated with RTE foods are the following: amount and frequency of
consumption of a food; frequency
and extent of contamination of a
food with Listeria; ability of the food
to support the growth of Listeria;
temperature of refrigerated/chilled
food storage; and duration of refrigerated/chilled storage. In addition, it
was agreed that multiple intervention
steps were required rather than any
one step to control the pathogen.
Another issue is the variable susceptibility of individuals at risk for infection. Guidelines with three annexes
(i.e., environmental monitoring in
processing areas; criteria for Listeria
in RTE foods; and microbiological
