Redwood Hill Farms of northern California recalls 8 days' output of goat milk. What separates listeria from its better-known food poisoning cousins e.coli and salmonella is its deadliness. The listeria microorganism can lurk in the intestines of any number of animals, including domestic pets, without the animal showing any sign of illness. It can be on vegetables that have been contaminated by manure. It's also found in soil, water, and dust.
Listeria is a hardy bacteria with lots of opportunities to spread.
It can continue to grow in freezing temperatures, proliferating in sealed packages or on the walls of refrigerators. At the upper end, it survives limited exposure to temperatures of up to 170 degrees. The good news is that enough heat does kill it. Nobody knows for sure. Food safety experts say it's possible the products were contaminated after cooking and before packaging.