The isolation of salmonellas from British pork sausages and sausage meat

Abstract

SUMMARY: Between 1969 and 1974, 1467 packets (3309 samples) of pork sausages and sausage meat produced by two large and two medium sized manufacturers and several local butchers were examined for the presence of salmonellas. Of these, 435 packets (786 samples) were found to contain salmonellas, but there was a wide variation in the isolation rates according to the producer. The salmonella incidence in samples from several small and two medium sized producers was low (0–11%) while the results from the two large producers investigated showed a striking difference, the rate of salmonella contamination in the product of one was low (about 2%) and in that of the other consistently high (40–60%).A comparison of liquid enrichment media, incubation temperatures and selective agar media was also carried out to determine the most efficient combination for the isolation of salmonellas from minced meat products. The results showed that (a) incubation of enrichment cultures at 43° C. yielded a consistently greater number of salmonella isolations than at 37° C., regardless of plating medium, (b) tetrathionate broth A (Rolfe) was superior to selenite broth as an enrichment medium at both 37 and 43° C. and (c) brilliant green agar gave better results than deoxycholate citrate sucrose agar and bismuth sulphite agar as a selective medium.