Food Microbiology Introduction PDF

College of Engineering and Food Science Department of Food Science FST 101 – Food Microbiology Introduction ALESSANDRA M. DOMANACO Assistant Professor IV  Microorganisms are living entities of microscopic size and include bacteria, viruses, yeasts and molds (...

College of Engineering and Food Science Department of Food Science FST 101 – Food Microbiology Introduction ALESSANDRA M. DOMANACO Assistant Professor IV  Microorganisms are living entities of microscopic size and include bacteria, viruses, yeasts and molds (together designated as fungi), algae, and protozoa. They are present everywhere, including in humans, animals, plants and other living creatures, soil, water, and the atmosphere, and they can multiply everywhere except in the atmosphere. Among the microorganisms, some molds, yeasts, bacteria, and viruses play both desirable and undesirable roles in our food.  What is MICROBIOLOGY? Microbiology is the science which includes the study of the occurrence and significance of bacteria, fungi, protozoa and algae which are the beginning and ending of intricate food chains upon which all life depends.  What is FOOD MICROBIOLOGY? - Is the study of the microorganisms that inhabit, create, or contaminate food. - Is the discipline that includes the microbiological aspects of food spoilage and food-borne diseases and their effective control and bioprocessing of foods for human consumption.  HISTORY OF FOOD MICROBIOLOGY Year Event 7000 BC - Beer manufacture in ancient Babylonia 6000 BC - Spoilage of prepared foods where first recorded in history 5000 BC - Pottery originated from Near East 3500 BC - Assyrians made wines 3000 BC - Sumerians first great livestock breeders and dairy men: - first to make butter - salted meats, fish fat, dried skins and barley were also associated to them 3000 BC - Egyptians manufactured milk, butter and cheese 1500 BC - Ancient Babylonians and Chinese prepared and consumed sausages 1000 BC - Meat preservation by Romans. Also used snow balls to preserve prawns and other foods  “The first person to appreciate and understand the presence and role of microorganisms in food was Pasteur. In 1837, he showed that the souring of milk was caused by microorganisms, and in about 1860 he used heat for the first time to destroy undesirable organisms in wine and beer. This process is now known as pasteurization.”  ROLES & SOURCES OF MICROORGANISMS IN FOOD ROLES OF MICROORGANISMS Roles of Microorganisms in Food 1. Food Spoilage 2. Food Poisoning 3. Food Preservation 4. Food Production  Food Spoilage When is a food fit to eat? “A product is fit for food if a discriminating consumer, knowing the story of its production and seeing the material itself, will eat it, and, conversely the same product is spoiled when such an examiner refuses it as food.” - Thom and Hunter (1924) Food Spoilage - Is defined as a process or change which renders a product undesirable or unacceptable for consumption  1 2 Microbial growth and Action of enzymes in the What causes foods to plant or animal food activity spoil??? 5 3 4 Physical changes Insects (ex.: bruises in foods) Chemical Reactions Classification of Foods by Ease of Spoilage: Stable or nonperishable foods - foods which do not spoil unless handled carelessly. Semiperishable foods - if properly handled and stored, will remain unspoiled for a fairly long period. Perishable foods - includes most of our important daily foods that spoil readily.  Food Poisoning - includes both illnesses caused by (1) the ingestion of toxins elaborated by the organisms and (2) infection of the host through the intestinal tract. - Can be the result of chemical poisoning or ingestion of toxicant. Food Intoxication – refers to food-borne illnesses caused by the presence of a bacterial toxin formed in the food. Food infection – refers to food-borne illnesses caused by the entrance of bacteria into the body through ingestion of contaminated foods and the reaction of the body to their presence.  FOOD-BORNE DISEASE: BACTERIA INTOXICATIONS INFECTIONS 1. Staphylococcal intoxication – 1. Salmonellosis – endotoxin of enterotoxin produced by Salmonella spp. Staphylococcus aureus. 2. Botulism – a neurotoxin produced 2. Clostridium perfringens illness – by Clostridium botulinum. enterotoxin released during sporulation of Clostridium perfringens type A in the intestinal tract 3. Bacillus cereus gastroenteritis – an enterotoxin released during lysis of Bacillus cereus in the intestinal tract 4. Enteropathogenic Escherichia coli infection – several serotypes of E. coli some invasive and some enterotoxigenic 5. Others: Yersiniosis, Shigellosis, Vibrio parahaemolyticus  Food Preservation Food Preservation OBJECTIVE: Lengthening the shelf-life of foods. Methods of Food Preservation 1. Asepsis 2. Removal of microorganisms 3. Maintenance of anearobic condition 4. Use of high temperatures 5. Use of low temperatures 6. Drying 7. Use of chemical preservatives 8. Irradiation 9. Mechanical destruction of mo’s 10. Combination of two or more of the above methods Principles of Food Preservation: ✓Prevention or delay of microbial decomposition ✓Prevention or delay of self-decomposition of the food ✓Prevention of damage because of insects, animals, mechanical causes, etc. How is Microbial Decomposition in Foods be Prevented? ASEPSIS – keeping out of microorganisms. Microbial decomposition of foods will be prevented if all spoilage organisms are killed and recontamination is prevented. Main concern… Kinds of microorganisms – may include spoilage organisms, those desirable in fermentation or even pathogenic microorganisms. Number of microorganisms – the more spoilage microorganisms are, the more likely food spoilage will be.  Food Production Production of Cultures for Food Fermentations Food Fermentation Foods and Enzymes from Microorganisms Sources of Microorganisms  Soil Air & Dust Plants Where are Microorganisms Animals, Birds, found? Utensils & etc. Equipments EVERYWHERE Gastrointestinal Water Tract Humans