Biopreservation of Meats and Meat Products - Food Biopreservation - page 35

(Hampikyan and Ugur 2007 ). The effectiveness of nisin in fermented meats
increased in combination with other antimicrobials, such as organic acids (reducing
the viable counts of S. Kentucky and S. aureus ; Scannell et al. 1997 ), lysozyme-
EDTA (inhibiting the growth of B. thermosphacta , L. curvatus , Ln. mesenteroides ,
L. monocytogenes and E. coli O157:H7; Gill and Holley 2000a ) or grape seed
extract (Sivarooban et al. 2007 ). Enterocins can inhibit Listeria in fermented meats,
as shown for enterocin CCM 4231 in dry fermented Hornád salami (Lauková et al.
1999 ) or enterocins A and B in espetec (traditional Spanish sausage; Aymerich et al.
2000 ). Addition of enterocin CCM 4231 (12,800 AU/g) from E. faecium CCM 4231
to Hornád salami meat mixture resulted in a reduction of L. monocytogenes by 1.67
log cycle immediately after addition of the bacteriocin (Lauková et al. 1999 ).
Although the added bacteriocin did not prevent growth of the listeria during storage
of samples in drying rooms at temperatures between 24 and 15 °C, viable counts
were signifi cantly lower that the controls. In espetec (a Spanish slightly-fermented
sausage), addition of enterocins A and B (648 AU/g) reduced the viable counts of
L. innocua below 50 CFU/g from the fi fth day until the end of the process (12 days)
of manufacturing (Aymerich et al. 2000 ).
In Italian sausages (“cacciatore”), enterocin 416K1 (10 AU/g, in the form of a
concentrated culture supernatant) decreased the levels of L. monocytogenes in sau-
sages by ca. 2.5 log CFU/g during the drying period (3 days), but failed to suppress
the pathogen during ripening (Sabia et al. 2003 ). Regarding enterocin AS-48, after
addition of this bacteriocin at 450 AU/g in a meat sausage model system, it was
observed that no viable listeria were detected after 6 and 9 days of incubation at
20 °C (Ananou et al. 2005a ), and also that viable counts of S. aureus were reduced
below detectable levels at the end of storage (Ananou et al. 2005b ). Also bacterio-
cins from leuconostocs have been tested in fermented meats. Addition of semi-
purifi ed bacteriocin of Ln. mesenteroides E131 improved the reduction of
L. monocytogenes viable counts in challenge experiments during fermented sausage
manufacturing (Drosinos et al. 2006 ).

4.2 Application of Protective Cultures

4.2.1 Raw Meats

Many LAB naturally associated with meats can grow at refrigeration temperatures.
Therefore, bacteriocin-producing strains of these LAB that do not have adverse
effects on meats can be selected as protective cultures for raw meat preservation
(Table 4.2 ). Previous works have demonstrated the effectiveness of bacteriocin-
producing L. sakei and L. curvatus strains in inhibiting L. monocytogenes or B. ther-
mosphacta in raw meat products. When L. sakei CWBI-B1365 and L. curvatus
CWBI-B28 (producers of sakacin G and P, respectively) were tested as protective
cultures on raw beef and poultry meat challenged with L. monocytogenes and stored
at 5 °C in sealed bags, inhibition of the listeria was found to depend greatly on the