Sample Preparation

Shipping and Storage
    Milk samples should be drawn in nonabsorbent, leak-proof containers (e.g. plastic vials or bags) and kept as cold as possible until testing (avoid freezing).  Sample containers should be filled to approximately 75% of capacity, allowing sufficient head-space for thorough mixing.  Samples taken for USDA verification purposes should be labeled according to MA requirements using bar code labels and/or a permanent marker. 

Samples should be shipped (unless picked up by MA personnel) by overnight express per MA guidelines.  The MA laboratory will supply plastic ice chests, smaller receptacles for packaging, and if necessary, "blue ice" blocks for shipment.  If available, our preference is to ship using wet ice secured in leak-proof bags.  Upon receipt by the MA, samples are checked for temperature and leakage and immediately refrigerated. 

Heating and Mixing
    Temper milk samples in a warm water bath to 42+1⁰ C.  Intermittent mixing while heating will speed the tempering process and ensure incorporation of any butterfat that has separated.  Immediately prior to testing, mix samples by repeated gentle inversion until homogeneous (we recommend at least 10x).   

Milk subjected to repeated heating and cooling or excessively long heating times will deteriorate and cause inaccurate test results.  Also, milk that is sour or that has been frozen is not suitable for testing. 

Temper samples in water bath until 42 C/108 F	Mix by gentle inversion, at  least 10 times	Immediately run sample

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