1.2 Flashcards
Four types of Microorganisms
Bacteria, Viruses, Parasites, and Fungi
Pathogen
A microorganism that causes illness
How do Pathogens get into food?
Most pathogens get into food from fecal material.The fecal material can enter food from humans or animals via unwashed hands, unwashed produce, raw meats, dirt, insects, or contaminated water. Some pathogens transmit directly from humans to food.
Bacterial spore
Some bacteria are capable of producing spores. A spore is a tough protein coat surrounding a dormant bacterial cell. Spores are very important because they allow some pathogen bacteria to survive high cooking temperatures, acid foods, dry foods, and other conditions that normally kill bacteria. There are three bacteria that cause food borne illness and produce spores: Clostridium botulinum, Clostridium perfringens, and Bacillus cereus.
Bacterial toxin
Some pathogen bacteria can produce chemical toxins that cause illness in humans. For example, Clostridium botulinum produces the botulism toxin, a very deadly toxin. Some bacterial toxins cannot be destroyed by cooking. So, you may properly cook a food item and it could still cause food borne illness if it has been contaminated with a toxin- producing pathogen. Foodborne illness caused by toxins are called “intoxications.” Other pathogens directly infect host cells called an “infection.” Remember, an intoxication can occur even if the toxin-producing microorganism has died.
Food borne infection
Food borne illness caused by pathogens that directly infect host cells.
Food borne intoxication
Food borne illness cause by toxins
Bacteria
acteria can cause food borne illness. They are living, single-celled organisms that can survive and grow in foods. Bacteria are very small. It would take approximately 400 million bacteria to equal the size of a grain of salt. As bacteria grow, they divide, doubling their numbers. Under favorable conditions ,they can reproduce very rapidly—often doubling in numbers every 20 minutes.
Viruses
Viruses are much smaller than bacteria. They consist of protein wrapped around genetic material. They can only reproduce inside a host cell. So, viruses are transmitted in food, but do not grow in food. There are two very important viruses that cause food borne illness: Hepatitis A and Norovirus. You may have heard of Norovirus as the cause of many of the cruise ship illness outbreaks. Viruses in foods usually originate from an infected worker or from contaminated water. Therefore, good employee hygiene as well as food from safe sources will help prevent viral food borne illnesses.
Parasites
Parasites are our third group of microorganisms. Parasites are larger than bacteria. They can be single-celled or multi-celled. They are similar to viruses in that they require a host cell to reproduce. And, like all other food borne illness organisms, they are excreted in human or animal feces where they can enter food or water. Trichinella is an example of a parasite.
It may be present in wild meats and has been associated with pork. A safe food supply will prevent this parasite from contaminating food. Giardia,Cryptosporidium, and Cyclospora are all parasites associated with fecal- contaminated water. A safe water supply and a safe and trusted food supplier will minimize this hazard.
Fungi
The last group, fungi, includes molds that can grow in foods. Most only cause spoilage, but a few mold species produce toxins that can cause illness. For this reason, it is best to discard moldy foods.
