Dairy farms in Kentucky, California, Kansas, and New Mexico are among latest to run afoul of federal regulations limiting antibiotic residues in cattle sold for slaughter as human food.

Each got into trouble the same way:  The U.S. Food and Drug Administration (FDA) came around to inspect the dairy operation and FDA inspectors looked at sales records to track animals that were slaughtered.   

If the animal was slaughter for human food, FDA checked with USDA’s Food Safely and Inspection Service to see if tissue samples for the specific dairy cow were tested for animal drug residues.

When those FSIS tests show residue levels at higher than allowed levels, the dairy gets a warning letter.

The most recent offenders include:

Dairy: Hugh A. Byron, Hillsboro, KY

Inspection Dates: Feb 14 & 15, 2011

Warning Letter Date: May 12, 2011

Violation(s):  Sold cow for slaughter as human food with residues of gentamicin (detectable level) and desfuroyllceftiofur (5.61 parts per million).  No level of gentamicin is tolerated by FDA, and the limit for ceftiofur is 0.4 ppm.

Notes: FDA says the dairy was not allowing for a pre-slaughter withdrawal period.

Dairy: Dick Van Dam Dairy, San Jacinto, CA

Inspection Dates: March 3 & 25, 2011

Warning Letter Date: May 18, 2011

VIolation(s):  Sold cow for slaughter as human food  with residue of flunixin in the liver tissue totaling 4.94 ppm. The FDA tolerance level for the antibiotic is 0.125 ppm in the liver tissue of cattle.

Notes:  FDA says the dairy was administering the animal drug without supervision by a licensed veterinarian as required for off-label uses.

Dairy: Syracuse Dairy, Syracuse, KS

Inspection Dates: April 19-21 and 28.

Warning Letter Date: June 15, 2011

Violation(s)  Sold a cow for slaughter as human food with residue of  0.383 ppm of flunixin in the liver tissue and 0.0489 ppm in the muscle tissue.  The tolerance level for the antibiotic in the liver tissue is 0.125 ppm and 0.025 in muscle tissue.

Notes: The presence of flunixin beyond tolerance levels means the meat is adulterated.

Dairy: N.S. Landaverde Cattle Ranch, Dexter, NM

Inspection Dates: May 10-11, 2011

Warning Letter Date: June 15, 2011

Violation(s): Sold a cow for slaughter as human food with residue levels of 20.73 ppm in the kidney tissue of an undisclosed animal drug with a tolerance level of 7.72 ppm.  Although the drug name was redacted from this warning letter, 7.72 ppm is the tolerance level for the widely used Neomycin.

Notes:  FDA says the New Mexico dairy is not keeping sufficient records, and it is possible these potentially harmful animal drug residues will enter the human food supply.

Each of the four dairies was given 15 business days to correct its violations.