Effects of Pasteurization or Added Sulphite on the Microbiology of Stored Vacuum Packed Baconburgers

Abstract

SUMMARY The flora of untreated vacuum packed baconburgers which were allowed to spoil at 5, 10 and 22° was dominated by atypical streptobacteria. Corynebacterium spp., micrococci, Bacillus spp. and lactic acid bacteria survived the post‐packing pasteurization treatments. There was no increase in bacterial numbers in 3 weeks at 5°, but at 10 and 22° group D streptococci grew and caused a souring spoilage of the product. Sodium metabisulphite, added to an initial level of 300 p/m SO2 retarded the growth of organisms, but had no qualitative effect on the flora. Of the two methods for extending the shelf life of vacuum packed baconburgers, the addition of SO2 was the safer, as the public health significance of group D streptococci is at present decidedly equivocal.

The Microbial Associations in British Fresh Sausages

“…2) in thegrowth of the contaminants and Gram negative bacteria predominated (Dyett & Shelley, 1962. These workers noted that the addition of the preservative delayed the onset of microbial growth-a similar response has been noticed in sulphited baconburgers (Gardner, 1968)-and resulted in a flora dominated by Gram positive bacteria which they subsequently identified with M . thermosphactum (E. J.…”

“…Preliminary studies indicate that SO, (final concentration, 450 ppm) prevents the growth of coliform bacteria, and checks for upwards of 24-48 h the growth of the other contaminants (Dyett & Shelley, 1962. On further storage, there is an increase in the number of yeasts and lactobacilli (Dowdell & Board, 1967, 1968 and Microbacterium thermospbtum becomes the numerically dominant contaminant (Gardner, 1966;Dowdell and Board, 1967 ;Gardner & Patton, 1969).…”

A note on the aerobic microflora of fresh and frozen porcine liver stored at 5°C

“…From livers in a polythene bag, 1 ml of drip was taken and added to 9 ml of the same diluent. Serial dilutions were plated out by the surface technique of Davis & Bell (1959) on a total count medium (TCM) (Gardner, 1968). Colonies were enumerated on the plates after incubation at 22" for 5-7 days.…”

“…The selection and identification of isolates from the total count plates is described elsewhere (Gardner, 1968).…”

The enumeration of microorganisms on Wiltshire bacon sides: a scheme for use in quality control

“…All samples were plated out on a total count medium with 4% NaCl (TCM4) (Gardner, 1968), but in the second half of the survey a selective medium for Yibrio (CVKA) (Gardner, 1973d) was also included. All plates were incubated for 3 days at 22" before colonies were enumerated.…”