Microorganisms and performance criteria for selective enrichment media 'CSB' used in Food chain microbiology according to ISO 22964.
ISO 22964 (2017) medium: CSB
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1 Qualitative control of Productivity
- Use a quantitative reference material or test suspension with a known number of Cronobacter sakazakii and Staphylococcus aureus.
- Inoculate one tube of test medium with < 100 cells of target microorganisms and with >103 cells of non-target organisms.
- Incubate at (41,5 ± 1) °C for (24 ± 2) h.
- Remove 10 µl and streak to a plate of specific medium for the target organism.
- Incubate at (41,5 ± 1) °C for (24 ± 2) h.
- Growth of target microorganisms should reach "Colour change of CSB; >10 colonies on CCI" with a characteristic reaction of: Yellow colour of CSB; Small to mediumsized (1mm to 3mm) blue to bluegreen colonies on CCI.
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2 Qualitative control of Productivity opt
- Use a quantitative reference material or test suspension with a known number of Cronobacter muytjensii and Staphylococcus aureus.
- Inoculate one tube of test medium with < 100 cells of target microorganisms and with >103 cells of non-target organisms.
- Incubate at (41,5 ± 1) °C for (24 ± 2) h.
- Remove 10 µl and streak to a plate of specific medium for the target organism.
- Incubate at (41,5 ± 1) °C for (24 ± 2) h.
- Growth of target microorganisms should reach "Colour change of CSB; >10 colonies on CCI" with a Characteristic reaction of: Yellow colour of CSB; Small to mediumsized (1mm to 3mm) blue to bluegreen colonies on CCI.
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Qualitative control of Selectivity
- Use a quantitative reference material or test suspension with a known number of Staphylococcus aureus.
- Inoculate one tube of test medium with >103 cells of non-target organisms.
- Incubate at (41,5 ± 1) °C for (24 ± 2) h.
- Remove 10 µl and streak to a plate of reference medium (TSA).
- Incubate at (41,5 ± 1) °C for (24 ± 2) h.
- Growth of non-target microorganisms should comply with the criteria: "Total or partial inhibition on TSA; <100 colonies".
Best Practice CSB
Qualitative control of Selectivity of liquid medium, mixed culture
Control strain | WDCM number | Incubation | Criteria | Characteristic reaction | |
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Cronobacter sakazakii | (41,5 ± 1) °C for (24 ± 2) h | Colour change of CSB; >10 colonies on CCI | Yellow colour of CSB; Small to mediumsized (1mm to 3mm) blue to bluegreen colonies on CCI | ||
+ Staphylococcus aureus | or | ||||
The best practice for Qualitative control of Productivity for media control of 'CSB' is based on the data displayed in this table according ISO 22964. |
Best Practice CSB
Qualitative control of Selectivity of liquid medium, mixed culture
Control strain | WDCM number | Incubation | Criteria | Characteristic reaction | |
---|---|---|---|---|---|
Cronobacter muytjensii | (41,5 ± 1) °C for (24 ± 2) h | Colour change of CSB; >10 colonies on CCI | Yellow colour of CSB; Small to mediumsized (1mm to 3mm) blue to bluegreen colonies on CCI | ||
+ Staphylococcus aureus | or | ||||
The best practice for Qualitative control of Productivity for media control of 'CSB' is based on the data displayed in this table according ISO 22964. |
Best Practice CSB
Qualitative control of Selectivity of liquid medium, single culture
Control strain | WDCM number | Ref. media | Incubation | Criteria | Characteristic reaction |
---|---|---|---|---|---|
Staphylococcus aureus | or | TSA | (41,5 ± 1) °C for (24 ± 2) h | Total or partial inhibition on TSA; <100 colonies | Purple colour of CSB |
The best practice for Qualitative control of Selectivity for media control of 'CSB' is based on the data displayed in this table according ISO 22964. |