I want to study the specific spoilage organism in some meat products, including Pseudomonas, lactic acid bacteria, Brochothrix thermosphacta ,Enterobacteriaceae, Micrococcus, yeast mould, and so on. Any suggestions?
you can begin to sow your homogenized samples above specific and selective medium, they can begin to diversify the various groups of bacteria that can be:
McConkeyagar for Enterobacteriaceae
MRS agar under anaerobic: for LAB
Mannitol Salt for Micrococcus
Sabouraud dextrose agar for Yeast
PSEUDOMONAS ISOLATION AGAR for Pseudomonas Spp
After this initial screening are used auxiliaries tests that can direct you to the use of some biochemical kit (API type).. but here depends on what tools you have available
Hello, you could take a swab from the meat and dilute in a suitable sterile diluent. which can be spread on a general purpose media. specific colonies could then be sub-cultured and identified using biochemical, microbiological or biomolecular techniques such gram staining
This paper might help: Isolation of lactic acid bacteria with inhibitory activity against pathogens and spoilage organisms associated with fresh meat.
Hi,
Only to inset the answers above. In case of using molecular techniques, I suggest to you additional prior-PCR step for manipulating the meat samples. Sample homogenates are good to be treated with Chelex 100 Molecular Biology Grade Resin or some analog to reduce the negative effect of possible PCR inhibitors in meat and to be used in reaction without preliminary enrichment step. The protocol includes centrifugation of the meat homogenate at 10 000 rpm for 5 min. Then the pellet has to be resuspended in 200 µl of 6% Chelex, vortexed and incubated for 20 min on 56 oC. The suspension must be boiled for 8 min and centrifuged at 14 000 rpm for 5 min. Two µl of supernatant were applied for PCR analysis. That is the way I did it in my previous research.
Best luck!
If you want to do all the things asked in your question then you have to homogenize the samples and do serial dilution and inoculate in different types of media for separation and isolation of different microorganisms. Then you have to test for different properties like biochemical, physiological and then go for 16S RNA (for bacteria) and 18S rRNA (for yeast and higher fungi) and some other genes.
If you want to just identify the mos present in your samples then you just go for NGS if you have the facility.
is it not possible to directly do a 16s rDNA PCR for bacteria and an ITS region PCR for fungi instead of trying to culture the organism? you could then get the product sequenced and zero-in on the pathogenic bacteria
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