AS 5013.9-2009 pdf free download

AS 5013.9-2009 pdf free download.Food microbiology Method 9: Examination for specific organisms Coliforms and Escherichia coil by the triplicate tube detection method.
6.1 Presumptive test for coliforms The procedure shall be as follows:
(a) Prepare the sample for microbiological examination in accordance with the instructions given in the relevant AS 5013 methods for the examination of specilc product.
(b) Using the technique described in AS 5013.11.1, prepare dilutions, as required, of the sample.
(C) Inoculate I mL of the appropriate dilution to be examined, or. where appropriate.
I mL of the original sample, into each of three tubes containing 10 rnL of LT broth
(5.1.4).
NOTE: The amount of material inoculated into each tube is calculated using the volume
(I mL) and the dilution used.
(d) lithe test is for coliforms. prepare a control tube by inoculating 10 mL of LT broth (5.1.4) with either of the reference cultures (4.1 or 4.2).
If testing for E. coil prepare control tubes of each reference culture by inoculating two 10 mL portions of LT broth (5.1.4) respectively with the two reference cultures.
(e) Mix the tubes by gentle rotation.
(fl Incubate at 30 ±1°C or37 ±1°C (see Note 3 in Clause I) for upto 48 h. and examine for gas production after 24 h and 48 h. Approximately 30 mm bef’ore each examinatioti. gently tap all tubes to guard against false negative results due to gas supersaturation.
(g) A presumptive positive reaction is indicated by the production of sufficient gas to fill the concavity of the Durham tube.
(h) Record the result of the presumptive test as positive if at least two of the set of three tubes are positive.
6.2 Confirinator’ test for coliforms The procedure shall he as follows:
(a) Subculture all cultures as they become positive in the presumptive test by streaking onto plates of EMB agar (5.1.2) and incubate at 30 ±1°C or 37 ±1°C for up to 18 h to 24 h.
(b) Colonies of typical coliforni appearance shall be regarded as coliforms.
NOTE: Typical coliform colonies may show any of the following characteristics:AS 5013.9-2009 pdf free download.