The most common food poisoning causes are unsanitary cooking preparation, foods not properly stored such as dairy products and mayonnaise, raw fish and oysters, unpasteurized foods, undercooked meats and eggs, and untreated water.

What Is Food Poisoning?

Food poisoning occurs when you eat food that is contaminated with bacteria or when you eat poisonous food such as mushrooms, poisonous plants, and poisonous animals such as the puffer fish.

How Does Food become Contaminated?

Many foods are already infected with microbes before you even begin to prepare it.  An infected hen can lay an egg that is infected with Salmonella, poultry can become infected during the slaughter process, and fruits and vegetables can become infected if they come in contact with feces.

During food preparation contamination can easily spread if hands are not washed properly, contaminated food is placed on a surface that comes in contact with non-contaminated food, and food not refrigerated properly are all breeding grounds for microbes.

The Most Common Sources of Food Poisoning

The FDA records maintains an extensive list of food poisoning sources including pathogenic bacteria, enterovirulent Escherichia coli Group, parasitic protozoa and worms, viruses, natural toxins,  and other pathogenic agents.

According to the Centers for Disease Control (CDC), the most common foodborne illnesses are Campylobacter, Salmonella, E. coli O157:H7, Calicivirus, or Norwalk-like virus.  For more in depth information on each of these see: CDC: Foodborne Illnesses