Molecular typing techniques to characterize the development of a lactic acid bacteria community on vacuum-packaged beef.
The development of a community of lactic acid bacteria from vacuum-packaged beef was investigated during a 6-week storage trial at 2 degrees C. The lactic acid bacteria population was monitored by using molecular techniques to identify a random sample of isolates at biweekly intervals during the storage trial. The polymerase chain reaction and a randomly amplified polymorphic DNA technique were used to identify and distinguish populations of lactic acid bacteria that developed during the storage trial. At week 0, the population of lactic acid bacteria was 3.5 log cfu/120 cm2 and by week 6, the population reached a maximum of 7.6 log cfu/120 cm2. A sampling from the week 0 population indicated a mixed community of Lactobacillus curvatus, Lactobacillus sakei and Leuconostoc spp. However, the sampling from week 6 indicated the population composition had changed to one where a single Leuconostoc strain predominated. This strain demonstrated antagonism towards the growth of other lactic acid bacteria isolated during the study. Additionally, the strain inhibited the growth of foodborne pathogens Escherichia coli O157:H7 and Listeria monocytogenes. DNA sequence data from the 16S rRNA gene suggested that the isolate may be a Leuconostoc gelidum strain.
Yost
Chris K
CK
Agriculture and Agri-Food Canada, Lacombe Research Centre, Alberta. yostc@em.agr.ca
Nattress
Frances M
FM
D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D005511:Food Handling / Q000379:methods; D018857:Food Packaging / Q000379:methods; D007778:Lactobacillus / Q000235:genetics / Q000254:growth & development*; D007934:Leuconostoc / Q000235:genetics / Q000254:growth & development*; D008460:Meat / Q000382:microbiology*; D018482:Muscle, Skeletal / Q000382:microbiology; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique; D013997:Time Factors; D014618:Vacuum
D012336:RNA, Ribosomal, 16S