Growth of Salmonella choleraesuis subspecies diarizonae serovar 61:k:1,5,(7) in broth and fresh mutton.

ABSTRACT

Three serovars of Salmonella choleraesuis (IIIb 61k1,5,(7), Enteritidis and Dublin) were grown in broths of pH 5.5 and 6.2 and incubated at 4, 6, 8 or 12 degrees C. Growth in the broth, measured by means of an increase of absorbance, was not observed below 8 degrees C. At 8 and 12 degrees C, the maximum growth rate (mu(max)), lag period and maximum absorbance level (max(abs)) varied according to serovar and pH. In general, serovar IIIb 61k1,5,(7) and serovar Enteritidis grew better than serovar Dublin. The effect of pH on lag period, seen for serovar IIIb 61k1,5,(7) and serovar Enteritidis at 8 degrees C, was absent at 12 degrees C, while the effect of pH regarding the mu(max) and the max(abs) was observed also at 12 degrees C. Furthermore, the growth serovar IIIb 61k1,5,(7) in normal and dark, firm and dry meat at 8 degrees C with ambient air in competition with the natural microbial flora was tested in minced meat and chops. Slow growth of serovar IIIb 61k1,5,(7) was observed in minced meat. The low virulence and the ordinary growth capabilities indicate that serovar IIIb 61k1,5,(7) will probably not represent a serious hazard to the public health.