Hormones and Antibiotics

This is a good read for an in-depth review about Food Safety:  The Agricultural Use of Antibiotics and its Implications for Human Health, check out this report from the US General Accounting Office.

Supplementing animal feed with antimicrobial agents to enhance growth has been common practice for more than 30 years and is estimated to constitute more than half the total antimicrobial use worldwide.  The potential public health consequences of this use have been debated; however, until recently, clear evidence of a health risk was not available.

Antibiotic resistance, the acquired ability of a pathogen to withstand an antibiotic that kills off its sensitive counterparts, originally arises from random mutations in existing genes or from intact genes that already serve a similar purpose.