Incubation period for culture media - (Apr/08/2015 )

Hello guys

I work in a pharmaceutical company and we follow British Pharmacopeia as the testing method.

Like in the testing for E. coli

As stated in the BP

""

4-2-1 Sample preparation and pre-incubation Prepare a sample using a 1 in 10 dilution of not less than 1 g of the product to be examined as described in general chapter 2.6.12, and use 10 mL or the quantity corresponding to 1 g or 1 mL to inoculate a suitable amount (determined as described under 3-4) of casein soya bean digest broth, mix and incubate at 30-35 °C for 18-24 h.

4-2-2 Selection and subculture Shake the container, transfer 1 mL of casein soya bean digest broth to 100 mL of MacConkey broth and incubate at 42-44 °C for 24-48 h. Subculture on a plate of MacConkey agar at 30-35 °C for 18-72 h.

""

I would like to know if it acceptable to have a incubation period longer than stated one?

like incubate the MacConkey broth (MCB) for  48-72+ h before subculture it to MCA

You should comply with the proocol.