Instructions for the Proper Collection

of Bulk Tank Milk Samples:

 Sampling Raw Milk:  Suggested Precautions

1.      Protect sampling instruments from exposure to contamination before and during use.

2.      When using a dipper, remove it from the sanitizing solution, drain it completely, and rinse it at least twice in milk before transferring the sample.

3.      Handle sample containers and caps aseptically.  Do not drop, lay down, touch the inside of, or otherwise contaminate the containers or caps.  If the container becomes contaminated or is suspect, it will be discarded and another will be used.

4.      Pre-sterilized bags and containers will not be carried in pockets of clothing.  Clipboards, covered containers, or boxes will be used to carry empty single-service containers.

5.      Multi-use sterile containers will be pre-cooled in the sample case as needed.  If moisture is present, containers will be rinsed with milk twice before filling with the test portion.

6.      Typically, a single universal sample will be taken and analyzed for all components to be tested.  If there becomes a need to collect separate samples, the sample will be taken first using aseptic technique.  Samples will be taken be taken from the same source and at the same time.  Regulations often govern how samples may be taken and the handling of those samples.

Recommended Protocols for Sampling Bulk Tank Milk:

1.      Measuring milk:  If the measuring stick is in the tank, dry the stick at milk level with a clean single-service paper towel, make measurement, and record.   If the measuring stick is outside the tank, sanitize the stick with chemical sanitizer and dry it at the milk level with a clean single-service paper towel.  Make the measurement and record the result.

2.      Agitate milk adequately:  Agitate tanks for 5 minutes if tanks have been filled within 30 minutes.  Agitate tanks for 10 minutes if tanks are larger than 3,800 liters (1,000 gallons).  Agitate tanks for 15 minutes if tank has been standing for more than 30 minutes after filling.

3.      Temperature check of milk:  Use a sanitized, standardized thermometer and record the result on the sample form.  Compare the accuracy of the bulk tank thermometer with the test thermometer monthly and record results.

4.      Collection of samples by hand:

A.     Rinse dipper 2 times in milk.  Dip at least 15-20 cm (6-8 inches) to obtain a representative sample.

B.     Do not hold sample container over milk while transferring the sample.

C.     Fill the sample containers not more than full (after closure) to permit proper mixing of the samples at the laboratory.  We will not test milk if containers are too full.  Whirl Pak Bags should be left with of the volume dedicated to air space after the bag is closed and sealed. 

D.     Submit two representative samples for analysis from the bulk tank with at least a combined amount of 100 ml and label with sample ID.  All tanks should be sampled and labeled individually, including identification of each tank.  Samples should be submitted for separate analysis and reporting.

E.     Record name, date, collection temp and time, sample ID or number on sample submission form.

F.     A temperature control should be taken at collection point (Temperature controls should be labeled as TC with time, date, temperature, and location identification).

G.    Samples should immediately be placed in a sample case with an appropriate refrigerant capable of maintaining a temperature between 0C to 4.4C.

H.    If samples will not arrive to laboratory within 24 hrs, the sample should be frozen. If Mycoplasma analysis is requested, keep one of the samples unfrozen and label Mycoplasma Analysis Requested.

I.       Dippers should be rinsed immediately with tap water and returned to their sanitizing solution.

J.      Sample reports should be prepared.

K.     Samples and sample data will be transported to the laboratory and analysis will begin within 24 hours of collection

L.     Refrain from shipping samples on weekends or holidays


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