Nisin and reutericyclin initially accelerated inactivation of
C. beijerinckii endospores at 600 MPa and 90
C, but both
compounds induced a tailing effect (Fig. 3A). Addition of nisin
resulted in a more rapid inactivation of C. sporogenes at 600 MPa
and 90
C relative to 90
C alone (Fig. 3B). The presence of reutericyclin produced a tailing effect in the inactivation of C. sporogenes
endospores (Fig. 3B).
Because the effects of nisin and reutericyclin on endospore
survival appeared to be species- or strain-specific, the effect of
these antimicrobials on B. amyloliquefaciens FAD 11/2 was assessed
(Fig. 4). B. amyloliquefaciens was more resistant to heat or pressure
than any of the Clostridium spp. investigated in this study. Reutericyclin had no effect on endospore survival at 90
C, or at 600 MPa
and 90
C. Nisin accelerated endospore inactivation at 90
C, and at
600 MPa and 90
C when compared to treatments with reutericyclin or without antimicrobials. In comparison to treatments at
90
C, pressure accelerated endospore inactivation in the absence
of antimicrobials or in the presence of reutericyclin. However,
relative to 90
C, pressure application did not accelerate endospore
inactivation when nisin was present.