The Centers for Disease Control and Prevention (CDC) estimate that contaminated meat- and poultry-related infections sicken up to 3 million people sick each year, killing at least 1,000—figures that are probably underreported. Most animal products in supermarkets and restaurants originate in CAFOs. Recalls of food products of animal origin contaminated with Salmonella, Listeria, Campylobacter, and E-Coli, are far from uncommon.

Studies consistently show that significant percentages of livestock and poultry products in retail food markets are contaminated with a variety of infectious bacteria. Various studies also show that a large percentage of bacteria in contaminated animal food products, such as MRSA, are resistant to multiple antibiotics.

Most instances of contamination of food with infectious bacteria likely take place in slaughter houses, where meat is accidently exposed to the contents of the stomachs and intestines of slaughtered animals. However, studies have verified that the high energy rations fed to animals in CAFOs to maximize feeding efficiency provide an ideal breeding environment for organisms that are particularly toxic to humans, such as the deadly E-Coli 0157:H7.

Switching animals from high-concentrate to high-forage rations has been found to reduce the shedding or potential contamination risks from E-Coli 0157:H7, suggesting that livestock raised on pasture or in grazing systems, rather than in CAFOs, presents lower food safety risks.

Grass-finished beef generally yields firm, normal size hearts, tongues and livers. Grass-finished beef livers rarely have abscesses and the color is dark red, compared to grain-fed livers, which are often a lighter color. Grain-finished beef has huge livers and large fat deposits around the top of the heart. The fat deposits do not affect the health of the heart, according USDA inspection standards, but the heart and all other organs work harder to deal with the constant diet of high-energy grains.

Processing grain rations is especially hard on the liver and results in liver from CAFOs being mushy, abnormally large, and often abscessed. Separate data is not kept for condemned livers from CAFOs, but it is common knowledge among USDA meat inspectors that many of the livers from grain-finished animals are condemned. It’s logical to be concerned about the safety of products from sick animals, even if USDA approved for human consumption.