Pharmaceutical microbiology - E. coli enumeration

[jelena2609982]

Dear All,

I have a type of product that contains dried herbs - and normally, it carrys a high microbiological burden, where even E. coli can be detected.
Pharmacopoeial requirements say that I should meet a maximum of 10 to the second of E. coli.
Which plate-count method would you recommend?

Thank you very much in advance,

Jelena

[JackBean]

How many of them do you know?

[jelena2609982]

There are a lot of E. coli methods available - several ISO methods, AOAC methods, rapid automated methods, pharmacopoeial methods...

I was refering to plate-count methods vs. MPN methods. Some people prefer plate count methods for samples where high bioburden is expected, while others prefer MPN methods, because they employ broths where even damaged organisms can recover and survive. Because of that, MPN methods sometimes yield higher values than plate count methods, but they are less accurate.

I was hoping for some real examples and experiences from people involved in similar bussineses.

Thanks for your reply,

Jelena

[lixiaoyi1981]

maybe you can try filtering

[jelena2609982]

Thanks for your reply, but my sample is not filterable. It is a sort of tea - we prepare the sample by using filter bags, and we homogenise with a stomacher, but still, a lot of small particles pass (pieces of herbal material). Filters would soon become blocked.

[pam009]

Microbiology specialist AES-CHEMUNEX has launched a new, unique product in its range of pre-poured chromogenic media that enable the simultaneous enumeration without any confirmation of E.Coli and Enterobacteriaceae. This method provides enumeration of both E.coli and Enterobacteriaceae in 24 hours using just one single plate and without any confirmation (Standard methods recommend the use of up to two plates per dilution and per organism with confirmation of the presumptive positives).
Recently validated and approved by AFNOR to ISO 16140 standard REBECCATM method can be used with food and animal feed. The procedure is carried out in just 2 steps - plating and reading - and requires no confirmation or specialised equipment. REBECCATM method can be used for single enumeration of E.Coli or simultaneous enumeration of E.coli and Enterobacteriaceae using a single plate.
After a 24 hours incubation step, E.Coli will appear as blue colonies and the other Enterobacteria will appear as pink to red due to a specific chromogenic substrate.

[JorgeLobo]

Add some sterile diluent in an appropriate stocmacher bag and use a stomacher to disperse. Plate and quantitate to cfu/gram. There are plenty of methods available - if one is specified by a gov body in your area (like BAM) I'd use that.