Identifying the bacterial community on the surface of Intralox™ belting in a meat boning room by culture-dependent and culture-independent 16S rDNA sequence analysis

We examined the bacterial community present on an Intralox™ conveyor belt system in an operating lamb boning room by sequencing the 16S ribosomal DNA (rDNA) of bacteria extracted in the presence or absence of cultivation. RFLP patterns for 16S rDNA clone library and cultures were generated using HaeIII and MspI restriction endonucleases. 16S rDNA amplicons produced 8 distinct RFLP pattern groups. RFLP groups I–IV were represented in the clone library and RFLP groups I and V–VIII were represented amongst the cultured isolates. Partial DNA sequences from each RFLP group revealed that all group I, II and VIII representatives were Pseudomonas spp., group III were Sphingomonas spp., group IV clones were most similar to an uncultured alpha proteobacterium, group V was similar to a Serratia spp., group VI with an Alcaligenes spp., and group VII with Microbacterium spp. Sphingomonads were numerically dominant in the culture-independent clone library and along with the group IV alpha proteobacterium were not represented amongst the cultured isolates. Serratia, Alcaligenes and Microbacterium spp. were only represented with cultured isolates. Pseudomonads were detected by both culture-dependent (84% of isolates) and culture-independent (12.5% of clones) methods and their presence at high frequency does pose the risk of product spoilage if transferred onto meat stored under aerobic conditions. The detection of sphingomonads in large numbers by the culture-independent method demands further analysis because sphingomonads may represent a new source of meat spoilage that has not been previously recognised in the meat processing environment. The 16S rDNA collections generated by both methods were important at representing the diversity of the bacterial population associated with an Intralox™ conveyor belt system.