The microbial flora of smoked pork loin and frankfurter sausage stored in different gas atmospheres at 4°C

Abstract

The development of the microflora of smoked pork loin and frankfurter sausage was followed during storage in vacuum, N2 and CO2 atmospheres at 4 degrees C. The total aerobic count on the smoked pork loin reached 10(7) organisms/g after 37 d in vacuum, 43 d in N2 and 49 d in CO2. The corresponding value for the sausage was 77 d in vacuum, while the growth stopped at 6 x 10(40 organisms/g after 98 d in N2, and at 4 x 10(2) organisms/g after 48 d in CO2. The predominant organisms on the fresh products were Bacillus spp., coryneform bacteria, Flavobacterium spp. and Pseudomonas spp. At the end of the storage time the microflora on both products in the three gas atmospheres, consisted mainly of Lactobacillus spp. and two large groups of organisms that could not be identified as any described genus. Some of the unidentified strains could be classified as a Lactobacillus sp. after subsequent subculturing on laboratory media. The numbers of Lactobacillus spp. at the end of storage decreased in the order, CO2 greater than N2 greater than vacuum. Lactobacillus viridescens generally constituted a substantial part of the Lactobacillus flora (5-72%). On the sausages two large uniform groups of unidentifiable homofermentative Lactobacillus spp. were also found.