Microorganisms and performance criteria for selective enrichment media 'MKTTn broth' used in Food chain microbiology according to ISO 6579-1.
ISO 6579-1 (2017) medium: MKTTn broth
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Qualitative control of Productivity
- Use a quantitative reference material or test suspension with a known number of Salmonella Typhimurium and Salmonella Enteritidis and Escherichia coli.
- Inoculate one tube of test medium with < 100 cells of target microorganisms and with >103 cells of non-target organisms.
- Incubate at 37 °C ± 1 °C for 24 h ± 3 h.
- Remove 10 µl and streak to a plate of specific medium for the target organism.
- Incubate at 37 °C ± 1 °C for 24 h ± 3 h.
- Growth of target microorganisms should reach ">10 characteristic colonies on XLD agar or other medium of choice" with a characteristic reaction of: Characteristic colonies according to each medium (see ISO 6579).
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1 Qualitative control of Selectivity
- Use a quantitative reference material or test suspension with a known number of Escherichia coli.
- Inoculate one tube of test medium with >103 cells of non-target organisms.
- Incubate at 37 °C ± 1 °C for 24 h ± 3 h.
- Remove 10 µl and streak to a plate of reference medium (TSA).
- Incubate at 37 °C ± 1 °C for 24 h ± 3 h.
- Growth of non-target microorganisms should comply with the criteria: "Partial inhibition ≤100 colonies on TSA".
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2 Qualitative control of Selectivity
- Use a quantitative reference material or test suspension with a known number of Enterococcus faecalis.
- Inoculate one tube of test medium with >103 cells of non-target organisms.
- Incubate at 37 °C ± 1 °C for 24 h ± 3 h.
- Remove 10 µl and streak to a plate of reference medium (TSA).
- Incubate at 37 °C ± 1 °C for 24 h ± 3 h.
- Growth of non-target microorganisms should comply with the criteria: "<10 colonies on TSA".
Best Practice MKTTn broth
Qualitative control of Selectivity of liquid medium, mixed culture
Control strain | WDCM number | Incubation | Criteria | Characteristic reaction | |
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Salmonella Typhimurium | 37 °C ± 1 °C for 24 h ± 3 h | >10 characteristic colonies on XLD agar or other medium of choice | Characteristic colonies according to each medium (see ISO 6579) | ||
+ Salmonella Enteritidis | |||||
+ Escherichia coli | or | ||||
+ Pseudomonas aeruginosa | |||||
The best practice for Qualitative control of Productivity for media control of 'MKTTn broth' is based on the data displayed in this table according ISO 6579-1. |
Best Practice MKTTn broth
Qualitative control of Selectivity of liquid medium, single culture
Control strain | WDCM number | Ref. media | Incubation | Criteria | Characteristic reaction |
---|---|---|---|---|---|
Escherichia coli | or | TSA | 37 °C ± 1 °C for 24 h ± 3 h | Partial inhibition ≤100 colonies on TSA | Partial inhibition ≤100 colonies on TSA |
The best practice for Qualitative control of Selectivity for media control of 'MKTTn broth' is based on the data displayed in this table according ISO 6579-1. |
Best Practice MKTTn broth
Qualitative control of Selectivity of liquid medium, single culture
Control strain | WDCM number | Ref. media | Incubation | Criteria | Characteristic reaction |
---|---|---|---|---|---|
Enterococcus faecalis | or | TSA | 37 °C ± 1 °C for 24 h ± 3 h | <10 colonies on TSA | <10 colonies on TSA |
The best practice for Qualitative control of Selectivity for media control of 'MKTTn broth' is based on the data displayed in this table according ISO 6579-1. |