Food Microbiology - An Introduction I. Microbiology - The study of “small life.” A. Bacteria: Eubacteria, Archaebacteria B. Viruses C. Fungi: Molds, Yeast D. Protozoa E. Others II. Bacteria: Small, unicellular organisms A. Structural Characteristics: 1. Cell wall & outer membrane 2. Cytoplasmic space/membrane 3. No well-defined nuclear envelope/membrane 4. One circular chromosome 5. Binary Fission/Geometric Replication B. Life Cycle/Phases of Growth: ! C. Composition 1. Water: Primary component of cells (~70%) 2. Remainder: a) Proteins, Polypeptides b) Carbohydrates/Sugars !1- Point of fermentation of grapes to wine or grains to beer or meat to sausage is so that foods dont’ decay and can last longer.KNOW THESE: Lag phase - when an organismsmoves into a new area or given new nutrients.It takes time to become in a good environment to grow.Log phase - exponential or geometric growthafter they like their environment. Stat phase - growth slows down bc of problems.Death - spoiled or cannot grow anymore.When a food is spoiled, you have a few billion cells in there. 9/3Rest of bacteria is:Some can break down protein and import those and reconfigure or metabolize into what they need(energy). May convert it into condiveroring.Bacteria composed of water mainly. Although they do have some membranes.They import carbohydrates. May take them and ferment them into other compounds. Most bacteria will ferment monosach glucose (6C sugar). Some ferment disach like lactose. Some cannot. Ex: Salmonela cant ferment lactose bc cant split the bond bet two sacharides - important for research.c) Lipids d) Minerals e) Nucleic Acids: DNA, RNA III. Food Microbiology: The Good, Bad, and Ugly A. Fermentation: Produces foods not otherwise possible! B. Pathogens: Microbial agents causing disease once consumed or after secretion of toxic substance into food that is consumed 1. Pathogen Types & Examples: a) Bacterial (Listeria monocytogenes, Salmonella, Clostridium botulinum) b) Fungal (Aspergillus spp., Fusarium spp.) c) Protozoal (Toxoplasma gondii, Giardia lamblia) d) Viral (Noroviruses, Hepatitis A) e) Nematodes/Trematodes (Trichina spiralis) 2. Significance of differing pathogen types and disease C. Spoilage: Food made undesirable via microbiological/enzymatic breakdown 1. Extent of spoilage based somewhat on extent to which food is made undesirable 2. Certain foods desirable to some consumers and completely undesirable to others IV. Important Historical Figures and Dates in Food Microbiology (pg. 3-8) A. Food Gathering (Pre-8000 BC): Foods typically eaten raw; trial and error on which foods were safe to eat and which were not. B. Food Producing/Preserving (To Present): Foods grown and animals, plants domesticated; foods are processed to enhance safety and quality/shelf stability 1. Boiling 2. Brewing of beer (China, 7000 BC) 3. Food storage in cool environments (preservation via reduced temperature storage) 4. Animal and plant husbandry/breeding 5. Fermentation of milk to cheese 6. Use of antimicrobials/salt to preserve foods (e.g., fish, meat) 7. Low temperature storage/freezing in snow !2Fats- Bacteria need lipids. They use lipids for energy extraction and to take fatty acids to form membrane lipids in bacteria. Many can synthesize the specific lipids they need and some cannot. Lipid profile will specify the type of lipid (short chain long? sat or unsat.)They need calcium, Mg and others for cofactors. Also Iron and calcium can be used to stabilizelipopolysach (outer component of bacteria). can Stimulate antibiotic production. Iron and Cacan neutralize the neg charges around it.They do have Ribosomes. Also have plasmid - a small circular piece of circular material like dna. Import to insert genes or operons to synthesize a protein from. Then translate certain proteins. They are naturally occurringso they can share genetic material bet bacterias (horizontal transfer).3 basic types of disease symptoms (NEED TO KNOW)Some placesmay be spoiled to uscan be a delicacyto others (consumers)C. Recent history and accomplishments in food preservation 1. 1680 - Antonie van Leeuwenhoek - Identifies microorganisms, doesn’t understand role in food spoilage 2. 1810 - Nicholas Appert - develops first procedure for canning of foods to preserve foods for Bonaparte’s army 3. 1860 - Pasteur - Identifies link between microbes and food spoilage; demonstrates thermal processing ability to preserve foods 4. 1880 - Commercial refrigeration introduced 5. 1910 - Refrigerated transport allowing cross-country shipping of produce 6. 1930 - Birdseye release frozen display cases for retail sale 7. 1943 - Hamburger irradiation D. Significant pieces of food processing/safety-related legislation 1. Ancient Babylon: Written mention of food processing and standards 2. 1516 - Bavaria, Germany: Reinheitsgebot (Beer Purity Law): Introduced a standard of identity for a fermented product 3. 1785 - Massachusetts Food Act: Made the commerce of unwholesome or impure/corrupted/contagious foods (meat, drinks) a punishable act 4. 1906 - Pure Food and Drug Act, Meat Inspection Act (21 U.S.C.) a) Pure Food and Drug Act: Added powers to Bureau of Chemistry (FDA) to seize unwholesome/adulterated foods from commerce and punish shippers b) Meat Inspection Act: Prevention of unsafe/sick animals from being processed for meat for human consumption (USDA-FSIS) 5. 1938 - Federal Food, Drug, and Cosmetic Act: Established food standards and definitions of adulteration and misbranding for foods (FDA) 6. 1957 - Poultry Products Inspection Act: Similar authority to USDA as Meat Inspection Act for poultry processing/safety (USDA-FSIS) 7. 1970 - Egg Products Inspection Act (USDA-FSIS) 8. 1973 - Low Acid Food Processing Regulations passed (21 CFR 113) (FDA) 9. 1996 - Pathogen Reduction/Hazard Analysis and Critical Control Point (HACCP) !39/5Food and Meat inspection act changed to FEDERAL meat inspection act.Pg. 8Preventing adulterated foods by the USDA to be given to people.Similar goals and responsibilities as the other acts above.-Not a law. More like regulations for low acid foods (like a can of corn or any can products so that Ph is dropped. This preserves microbio safety and shelf life.Very Important. Passed mainly for beef products. It utilized the federal meat insp act for bases of authority. This proces became mandatory for food regulated products (meat, poultry)Systems; Final Rule (USDA-FSIS) 10. 2009 - Prevention of Salmonella Enteriditis in Shell