(Editor’s Note: This is Part 2 of a three-part series on foodborne illnesses and food safety.) Microorganisms are very small living things that can only be seen with a microscope. There are four types of microorganisms: bacteria, viruses, parasites and fungi. These microorganisms can be classified as either pathogens or spoilage microorganisms. Pathogens cannot be seen, tasted or smelled and can cause illness. Spoilage microorganisms cause food to look, smell, taste, and feel spoiled; however, they do not cause illness. Foodborne illnesses caused by microorganisms can be classified into three categories: infections, intoxications or toxin-mediated infections. A foodborne infection occurs after a person eats food contaminated with harmful microorganisms.The microorganisms multiply in the intestines of the person and causes an illness. Symptoms do not appear immediately. Campylobacterosis, salmonellosis, listeriosis, hepatatis A, and Norwalk- like virus gastroenteritis are examples of foodborne infections. A foodborne intoxication occurs after a person eats a food contaminated with a toxin. The toxin is produced by a harmful microorganism, and it is the toxin that causes an illness. Symptoms usually appear within a few hours. Examples of foodborne intoxications include botulism and staphylococcus. A toxin mediated infection occurs after a person eats a food that is contaminated with a harmful microorganism, and the microorganism produces a toxin that causes illness. This microorganism grows in the intestine of the person and produces a toxin that causes illness. E.coli 0157:H7 is a toxin- mediated infection. If two or more people have the same foodborne illness after eating the same food, it is known as an outbreak. However, if only one person is diagnosed with botulism or chemical poisoning it is not considered an outbreak. Besides salmonella being in the news recently, listeriosis was also featured concerning poultry in a poultry processing plant. Listeriosis is a foodborne infection. Listeriosis is a bacteria that is found in soil and ground water and on plants. Animals and people carry listeria and never become sick. Most infections occur from eating contaminated food. More than 2,500 people in the United States become sick each year with listeriosis, and two out of five die. People who are at the greatest risk of listeria are pregnant women and their unborn babies, newborns, elderly and people with weakened immune systems. According to the Center for Disease Control, pregnant women are 20 times more likely than other healthy adults to get listeriosis. One-third of all listeriosis cases occur during pregnancy. Symptoms for listeriosis take from days to weeks to appear. Sometimes it takes up to three weeks before a person exhibits symptoms which are often mild and resemble flu-like symptoms. Other times, they are more serious and cause infections that spread to the nervous systems and cause headaches, convulsions and loss of balance. Also, infection may cause meningitis, encephalitis, septicemia and cervical infection in pregnant women, which may result in spontaneous abortion or stillbirth. Foods that are involved in listeriosis outbreaks include unpasteurized milk and cheese, ice cream, frozen yogurt, raw vegetables, poultry, meats, seafood and prepared and chilled ready-to-eat foods (soft cheese and deli meats). It is recommended that all luncheon meats, deli meats and hot dogs be heated until steaming hot before they are eaten. Listeria can grow in temperatures below 40 degrees, so eat opened packages of these meats within three days. Other sources of listeriosis include soil, water, damp environments, humans and domestic and wild animals. Careful, sanitary hygiene practices should be taken when around domestic and wild animals, especially when cleaning cat-litter. Since, listeriosis is found in the intestinal tracts and feces of animals, caution should be taken when cleaning cat-litter, and pregnant women should take extra precaution during this time. Another foodborne illness that often makes headlines in the news is staphylococcus. Staphylococcus organisms are capable of producing very-heat resistant toxins. The toxins, rather than the actual bacteria, are responsible for causing foodborne illnesses. Common symptoms include nausea, vomiting, cramps, sweating, chills, weak pulse, shock and lowered body temperature. It may take one to seven hours to occur, and recovery usually occurs within two days. Staphylococcus is found in the nose and throat and on the hair and skin of more than half of the healthy population. Infected wounds, lesions, boils and mucous spread by coughs and sneezes of people with respiratory infection are other sources of contamination. Any food that requires handling in its preparation can become contaminated. Foods that best support growth include protein foods such as meats, poultry and fish; cream sauces and salads such as ham, turkey, and potato; and puddings, custards and cream-filled pastries. Temperature control is one of the most effective ways to control staphylococcal intoxication. Also, it is important to use good hygiene to help prevent contamination. Cook foods throughly, then cool foods in shallow containers in refrigerators. Do not cool foods on the stove or counter top. Keep meat salads, potato salads, cream pies, puddings and pastries chilled until served. Avoid leaving foods at room temperatures for more than two hours. If food is left out for two hours, throw it out. Safe food handling begins at the grocery store and follows through storage, preparation, serving and saving and reheating leftovers. Next weeks article will feature foodborne viruses and how to prevent foodborne illnesses by following the 4 Cs of food safety.