S.I. No. 37/1937 - Milk and Dairies (Bacteriological Examination) Regulations, 1936.

STATUTORY RULES AND ORDERS. 1937. No. 37.

MILK AND DAIRIES (BACTERIOLOGICAL EXAMINATION) REGULATIONS, 1936.

The Minister for Local Government and Public Health in exercise of the powers conferred on him by section 52, section 59, section 6 and sub-section (2) of section 15 of the Milk and Dairies Act, 1935 , hereby makes the following Regulations, that is to say:—

1. These Regulations may be cited as The Milk and Dairies (Bacteriological Examination) Regulations, 1936.

2. The Interpretation Act, 1923 , shall apply to the interpretation of these Regulations in the same manner in which it applies to the interpretation of an Act of the Oireachtas.

3. For the purposes of sub-section (3) of section 59 of the Milk and Dairies Act, 1935 , the prescribed number of bacteria per unit volume shall be 500,000 per cubic centimetre.

4. When a sample of milk is submitted to a bacteriological examiner in accordance with section 51 of the Milk and Dairies Act, 1935 , for an examination and test to determine for any of the purposes of the said Act the number of bacteria per unit volume contained in such sample such examination and test shall be carried out by such bacteriological examiner in the manner set forth in the first schedule to these Regulations.

5. When a sample of milk is submitted to a bacteriological examiner in accordance with section 51 of the Milk and Dairies Act, 1935 , for an examination and test to determine for any of the purposes of the said Act the nature of any micro-organisms, or antibodies to micro-organisms contained in such sample such examination and test shall be carried out by such bacteriological examiner in the manner set forth in the second schedule to these Regulations.

FIRST SCHEDULE.

Manner of examining and testing a sample of milk to determine the number of bacteria per unit volume.

1. (a) A culture medium shall be used consisting of peptone, "lab lemco" and agar dissolved in tap water.

(b) The ingredients of the culture medium shall be in the following proportions, that is to say—

2. The culture medium shall either have a reaction between +5 and +10 on Eyre's scale or have a hydrogen ion concentration of pH 6.8, and if necessary acid or alkali may be added in order that the medium may comply with this paragraph.

3. After it has been ascertained that the culture medium complies with the immediately preceding paragraph the culture medium shall be filtered and sterilised.

4. A suitable quantity of the culture medium, so filtered and sterilised, together with a quantity or quantities of the milk to be tested determined in accordance with the next following paragraph shall be plated out on one or more Petri dishes.

5. The quantity of milk to be introduced into any one plate shall be either 1/10, 1/100 or 1/1000 part of a cubic centimetre according as the nature of the test being made and the other circumstances require.

6. The plate or plates made under the two immediately preceding paragraphs shall be placed in an incubator at a temperature of 37 degrees Centigrade and shall be there incubated at the said temperature for 48 hours.

7. In the following portion of this Schedule the expression "countable colony" means a colony of bacteria visible to and capable of being counted by the naked eye of a person with normal vision.

8. After incubation the plate, or, where there are two or more plates, the plate containing the greatest quantity of milk on which there are countable colonies shall be examined and the number of such colonies thereon immediately after incubation shall be ascertained.

9. From the number ascertained under the immediately preceding paragraph the number of bacteria in one cubic centimetre of the milk tested shall be ascertained by calculation, on the assumption that each countable colony represents one bacterium in such milk immediately before testing.

10. Where the number of colonies of bacteria visible to the naked eye of a person with normal vision on a plate containing 1/1000 part of a cubic centimetre of milk is so great, that such colonies cannot be counted it shall be assumed that the number of bacteria contained in the milk from a sample of which the plates were prepared was greater than 500,000 in one cubic centimetre.

SECOND SCHEDULE.

Manner of examining and testing a sample of milk to determine the nature of any micro-organisms or antibodies to micro-organisms contained therein.

1. The nature of the micro-organisms or antibodies shall first be examined by either microscopic cultural or serological methods or by a combination of any two or all of such methods according as the bacteriological examiner considers necessary in the circumstances.

2. Where the bacteriological examiner considers it necessary he may carry out further tests by means of biological examination.

3. Suitable chemical and physical tests may be carried out to obtain corroboration of the results obtained by means of the examination and tests carried out under the two preceding paragraphs.

Given under the hand and Seal of the Minister for Local Government and Public Health dated this Eighteenth day of December, One Thousand Nine Hundred and Thirty-six.

(Sighnithe) SEÁN T. O CEALLAIGH,

Minister for Local Government and Public Health.