Consumers who have purchased raw milk from Misty Meadow Farm in Bernville, Berks County, any time after April 16 should discard it immediately due to the risk of Listeria contamination, Agriculture Secretary Dennis Wolff said today.  Raw milk is milk that has not been pasteurized or homogenized.  "During routine inspection of the dairy, a preliminary test showed the presence of Listeria bacteria in some raw milk samples," said Wolff. "If consumers have raw milk from this farm, they should discard it immediately."  The Department of Agriculture has suspended sales of raw milk at the dairy and is ensuring that corrective action is taken. Samples were taken from the farm during routine testing on May 7 and tested positive for Listeria on May 10.