596 Modern Food Microbiology
Figure 25–2 Change in cell populations of strains F5069/(4b) in pH-adjusted orange serum incubated at 30
◦ C.
Initial cell concentration was 2.2 × 10
6 colony-forming units (cfu)/ml. Source: From Parish and Higgins,
102 copyright c
1989 by International Association of Milk, Food and Environmental Sanitarians, used with permission.
8 days when incubated at 30
◦ C, but death occurred at 30
◦ C when the organism was inoculated into
sterile cabbage juice adjusted to a pH <4.6 with lactic acid.
21 At a pH of 5.05 and incubation at 5
◦ C,
strain Scott A did not grow in cottage cheese with an inoculum of ∼10
3 cfu/g.
104
Combined Effect of pH and NaCl
The interaction of pH with NaCl and incubation temperature has been the subject of several
studies.
19,21 The latter investigators used factorially designed experiments to determine the interaction of these parameters on the growth and survival of a human isolate (serovar 4b); some of their
Figure 25–2 Change in cell populations of strains F5069/(4b) in pH-adjusted orange serum incubated at 30
◦ C.
Initial cell concentration was 2.2 × 10
6 colony-forming units (cfu)/ml. Source: From Parish and Higgins,
102 copyright c
1989 by International Association of Milk, Food and Environmental Sanitarians, used with permission.
8 days when incubated at 30
◦ C, but death occurred at 30
◦ C when the organism was inoculated into
sterile cabbage juice adjusted to a pH <4.6 with lactic acid.
21 At a pH of 5.05 and incubation at 5
◦ C,
strain Scott A did not grow in cottage cheese with an inoculum of ∼10
3 cfu/g.
104
Combined Effect of pH and NaCl
The interaction of pH with NaCl and incubation temperature has been the subject of several
studies.
19,21 The latter investigators used factorially designed experiments to determine the interaction of these parameters on the growth and survival of a human isolate (serovar 4b); some of their