Food Microbiology and Foodborne Illness(Taken from EC 92-2307 by Julie A. Albrecht and Susan S. Sumner archived/posted in Digital Commons, University of Nebraska-Lincoln) Show
Bacteria, yeasts, and mold are microorganisms associated with foods. The individual microorganism cannot be seen without the aid of a microscope. The size of these microorganisms are measured in microns (1 micron is 1/1000 of a millimeter or U25,40A of an inch). More than a thousand microorganisms in a cluster are barely visible to the eye. Microorganisms may be classified into three groups according to their activity:
Microorganisms can be found virtually everywhere. Bacteria and molds are found in the soil and water. Yeasts are found mainly in the soil. Plant and animal food products support the growth of microorganisms. Bacteria have been detected on plants and animals; molds are usually found on fruits and vegetables; yeasts are generally found on fruits. Many bacteria are part of the normal microflora of the intestinal tracts of man and animals.
Growth Factors of MicroorganismsAll microorganisms require moisture, a food source, enough time, and suitable temperatures to grow and multiply. MoistureMicroorganisms are composed of about 80% water which is an essential requirement for microorganisms to grow. Moisture requirements vary for each species of microorganism. In general bacteria need more water than yeasts. Yeasts require more water than molds to grow. If water is not available for microorganisms in a food product, the microorganisms may remain but will not grow and multiply. Certain components in foods will make water unavailable for microorganisms (and thus can inhibit growth). Salt & SugarSalt and sugar added to foods "tie" up water and lower the water activity. When enough salt or sugar is added to a food, the water activity will be lowered to a level that will prevent microorganisms from growing.
Some microorganisms are tolerant of certain conditions.
FoodMicroorganisms need a source of nutrients to grow and multiply. TimeMicroorganisms need time to grow and multiply. Under favorable conditions (enough moisture and food available with the desired temperature), cell division (reproductive growth) may occur every 20 to 30 minutes. The time for a microbial cell to double is called the generation time. TemperatureMicroorganisms grow best within certain temperature ranges. Bacteria are classified into three groups, depending on the temperature at which the bacteria grows best.
Other factors affecting growth:
The bacteria which cause foodborne illness in humans grow best at body temperature (98.6°F - mesophilic bacteria). See more about illness-causing bacteria, Hepatitis A virus and parasites ? For more information contact: Julie Albrecht, Ph.D., R.D., UNL Extension Food Specialist References IAMFES. 1991. Procedures to Implement the IFT Scientific Status Summary. 1988. Bacteria Ryser, E.T. and Marth, E.H. 1989. "New foodborne USDA-FSIS. 1989. FSIS Facts, Preventable Who is most likely responsible for foodborne illness quizlet?The top two locations of food preparation that are responsible for the highest number of reported foodborne disease outbreak illnesses are: catering or banquet facilities and private homes. . restaurants and institutions.
Which of the following is a common and serious foodborne pathogen quizlet?Salmonella is the most common cause of foodborne illness in the United States.
Which contaminant poses the greatest foodborne illness risk quizlet?Of all the microorganisms, bacteria are the greatest threat to food safety.
Which of the following groups of people is least susceptible to severe foodborne illness?Young, healthy adults are the least susceptible to foodborne illness.
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