Health Canada
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Food and Nutrition

Microbiological Examination of Milk

Health Protection Branch - Ottawa

Official Method MFO-7
November 30, 1981

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1. APPLICATION

This method shall be used for the determination of total aerobic bacteria (Aerobic Colony Count) in (naming the flavour) milk, (naming the flavour) partly (partially) skimmed milk, milk for manufacture into dairy products, (naming the flavour) partly (partially) skimmed milk with added milk solids in accordance with sub-paragraph (e) of Section B.08.016, sub-paragraph (f) of Section B.08.018, sub-paragraph (a) of Section B.08.024 and sub-paragraph (g) of Section B.08.026 of the Food and Drug Regulations, respectively.

2. SAMPLING

2.1 Definition of Terms

2.1.1 Lot: A batch or production unit which may be identified by the same code. When there is no code identification, a lot may be considered as (a) that quantity of product produced under essentially the same conditions, at the same establishment and representing no more than one day's production; or, (b) the quantity of the same kind of product from one and the same manufacturer available for sampling at a fixed location.

2.1.2 Sample: The sample units (subsamples) taken from a lot for analysis.

2.1.3 Sample Unit: Usually a consumer size container of the product, and should consist of a minimum of 100 ml. A sample unit is often referred to as a subsample.

2.1.4 Analytical Unit: That amount of product withdrawn from the sample unit for analysis.

2.2 Collection of Samples

2.2.1 A sample, consisting of five sample units drawn at random from each lot, shall be taken.

2.2.2 Each sample unit shall consist of at least 100 ml.

2.2.3 Collect original unopened containers wherever possible.

2.2.4 More than one sample unit may be collected from large institutional or bulk containers when the total number of sample units required exceeds the number of containers in the lot. When the lot consists of containers smaller than 100 ml, a sample unit will consist of more than one containers (e.g., four 25 ml containers in each sample unit).

2.2.5 Employ aseptic techniques in collecting the sample units when sampling from bulk. Place each collected sample unit into a separate sterile container.

2.2.6 Keep sample units refrigerated (0-5°C) during transport.