LAB and the LAB plus CFE were more effective in reducing
L. monocytogenes after 8 weeks of refrigerated storage (2- and
3.3-log reductions, respectively). This study showed that it is
possible to use LAB as an aid to further reduce L. monocytogenes throughout storage.
Now we see that there are applications of LAB to control
L. monocytogenes in the product itself, but these have not been
used extensively by industry despite their technological potential. A highly related application, the control of environmental
L. monocytogenes by LAB, may see greater potential in the near
future due to some promising results. We present two examples representative of this area of research.
Ndahetuye et al. 5 evaluated the attachment of three LAB
strains—P. acidilactici, L. amylovorus and L. animalis—to stainless steel coupons from a deli slicer and their ability to inhibit
the attachment of L. monocytogenes. L. animalis exhibited the
greatest hydrophobicity ( 26.3%), and its adherence increased
sharply from 24 to 72 hours, whereas L. amylovorus yielded
the lowest hydrophobicity ( 3.86%) and was weakly adherent.
Although P. acidilactici had moderate hydrophobicity ( 10.1%),
it adhered strongly. Three conditions were simulated to evaluate the ability of the LAB cocktail [108 colony-forming units
(CFU)/mL] to competitively exclude L. monocytogenes (103
CFU/mL) on the surface of the coupons. The coupons were
pretreated with the LAB cocktail for 24 hours prior to the
addition of L. monocytogenes, simultaneously treated with the
LAB cocktail and L. monocytogenes, or pretreated with L. monocytogenes 24 hours before the addition of the LAB cocktail. The
LAB cocktail was able to reduce the attachment of L. monocytogenes significantly, indicating a possible role for LAB as a
biosanitizer in the food industry.
Zhao et al. 6 determined that treating Listeria-laden biofilms with the two competitive exclusion isolates—Lactococcus
lactis subsp. lactis strain C-1-92 and Enterococcus durans strain
152—individually at either 4 or 8 °C for 3 weeks substantially
reduced or eliminated listeriae in the biofilms. Treatment with
L. lactis subsp. lactis strain C-1-92 and E. durans strain 152 at 4
°C for 3 weeks reduced the population of L. monocytogenes in a
biofilm from 7.1- to 7.7-log CFU/cm2 to 3.0- to 4.5-log CFU/
cm2 and to 3.1- to 5.2-log CFU/cm2, respectively, and treatment at 8 °C for 3 weeks reduced L. monocytogenes from 7.5- to
8.3-log CFU/cm2 to 2.4- to 3.5-log CFU/cm2 and to 3.8- to
5.2-log CFU/cm2, respectively, depending on the coupon material. The researchers combined the isolates and evaluated the
control of Listeria in floor drains of an RTE poultry processing
plant. The results showed that treating the drains with the isolates four times in the first week eliminated detectable Listeria
from five of six drains tested, and the drains remained free of
detectable Listeria for 13 weeks following the first four treatments. The authors indicated that certain bacteria, including
LAB, can effectively reduce Listeria contamination in biofilms
and floor drains of a plant producing RTE poultry products.
Studies performed in our food safety laboratories have further demonstrated that LAB have the ability and potential to
To The Test
Testing For The Food & Feed Industry
; The right testing protocol for your food and feed analysis.
; The most cost-effective solution (only the tests you need).
; A personal commitment to work in partnership with you.
For 100 Years
100 Years Of Trust 100 Years Of Trust
100 Years Of Trust 100 Years Of Trust st
1916 - 2016