Food and Industrial Microbiology Fall 2024 PDF

Food and industrial microbiology Dr. Moroianu Extra credit Create one original game to better remember materials Must incorporate key terms and definitions (2 points) Provide rules (2 points) Easy to follow/share with other students (1 points) Total five points ext...

Food and industrial microbiology Dr. Moroianu Extra credit Create one original game to better remember materials Must incorporate key terms and definitions (2 points) Provide rules (2 points) Easy to follow/share with other students (1 points) Total five points extra credit Games should be specific to unit 2 content, some ideas are: Using flashcards as “playing cards” in a game Creating a game board where you move around the board by giving correct definitions A matching or search game where you match terms to definitions Games would not count would be Something that utilizes only terms (no definitions or vise versa) Games that do not require critical thinking (word bank, find this word in a word-search) Submit to BlackBoard through Unit 2 Extra Credit Portal by Nov. 8 11:59pm. 2  Animal viruses 1. Attachment: viruses attach to the cell membrane 2. Entry by receptor-mediated endocytosis or fusion 3. Uncoating by viral or host enzymes 4. Biosynthesis: production of nucleic acid and proteins 5. Maturation: nucleic acid and capsid proteins assemble 6. Release by budding (enveloped viruses) or rupture 3 Clarification on Enveloped Viruses Envelope created due to budding exit from cell Do not necessarily kill the cell, however cell may be damaged and die due to this process Are less virulent, as compared to non-enveloped viruses, why is that? Envelope is fragile, and typically cannot exist outside the body Can be broken down using things like alcohol, which non-enveloped viruses are resistant to Also more sensitive to changes in environment 4 Danger of Enveloped Viruses Can change over short period of time Greater adaptability Majority of viruses that are pathogenic against humans are enveloped including: HIV, influenza, measles, and COVID-19 Transmitted via transfer of body fluids In contrast to non-enveloped viruses that are transmitted via fecal oral route 5 Biosynthesis of DNA viruses DNA viruses replicate their DNA in the nucleus of the host using viral enzymes Synthesize capsid in the cytoplasm using host cell enzymes 6 DNA Viruses- Examples Poxviridae Double-stranded DNA, enveloped Cause skin lesions Vaccinia and smallpox viruses (Orthopoxvirus) Contagious by household contact Eradicated due to successful vaccine 7  DNA Viruses- Examples Herpesviridae Double-stranded DNA, enveloped HHV-1 and HHV-2-Simplexvirus; cause cold sores HHV-3-Varicellovirus; causes chickenpox HHV-4-Lymphocryptovirus; causes mononucleosis HHV-5-Cytomegalovirus HHV-6 and HHV-7-Roseolovirus HHV-8-Rhadinovirus; causes Kaposi’s sarcoma 8  DNA Viruses- Examples Papovaviridae Double-stranded DNA, nonenveloped Papillomavirus Causes warts Can transform cells and cause cancer Human papillomavirus (HPV) Transmission is primarily through skin-to-skin or skin-to-mucosa contact 9 RNA viruses DNA viruses are mostly double- stranded while RNA viruses are Examples single-stranded Enterovirus Poliovirus and coxsackievirus RNA mutation rate is higher than the DNA mutation rate Rhinovirus Common cold DNA replication takes place in the Hepatitis A virus nucleus while RNA replication takes Rubivirus place in the cytoplasm Rubella DNA viruses are stable while RNA Lyssavirus viruses are unstable Rabies 10 Viruses and cancer Several types of cancer are caused by viruses May develop long after a viral infection Cancers caused by viruses are not contagious Oncogenes transform normal cells into cancerous cells Oncogenic viruses become integrated into the host cell’s DNA and induce tumors Human tumor viruses account for an estimated 12% to 20% of cancers worldwide Epstein-Barr virus, human papilloma virus, hepatitis B virus, and human herpes virus-8 are the most common cancer causing viruses 11 Another infectious agent: Prions Prions- Proteinaceous infectious particles Induce abnormal folding of prion proteins that are found most abundantly in the brain Inherited and transmissible by ingestion, transplant, and surgical instruments Transmissible Spongiform encephalopathies (TSE, prion disease) Mad cows disease, Creutzfeldt-Jakob disease Spread through meat consumption and bone meal 12 https://www.youtube.com/watch?v=Cubu-k7kSvw 13 Another infectious agent: Prions Symptoms include: confusion and dementia, followed by memory loss, hallucinations, personality changes, speech impairment, motor impairment, and seizures Fatal within days to years Research now finding increasing evidence that prions may be the cause of neurodegenerative diseases (NDs), including Alzheimer's, Parkinson's and Lou Gehrig's diseases 14 -End Microbial Classification- 15 Applied Microbiology and Biotechnology Microbes are harnessed in diverse ways for specific metabolic tasks that can provide practical benefits to humans Applied microbiology – microbes are used to treat wastewater and bioremediate damaged environments Industrial microbiology – use of microbes in making food, medical, manufacturing, and agricultural products Biotechnology – uses microbes for practical applications Fermentation – controlled culture of microbes to produce desired organic compounds 16 Water and Wastewater Treatment Water purification – In most cities, water is treated in a stepwise process before it is supplied to consumers Primary phase – removes floating, bulky physical objects Secondary phase – removes the organic matter by biodegradation, natural bioremediation in a large digester forming sludge which is aerated by injection and stirred Tertiary phase – filtration, disinfection, and removal of chemical pollutants Important as many infectious pathogens are communicable via fecal matter or poor hygiene 17 The Role of Microorganisms in Water Quality The transmission of infectious diseases Microbes are filtered from water that percolates into groundwater Some pathogens are transmitted to humans in drinking and recreational water from feces Typhoid fever Cholera  Monitoring Fecal Contamination of Water Indicator organisms Used to detect fecal contamination of water Coliforms Aerobic or facultatively anaerobic, gram-negative, non- endospore-forming rod bacteria Ferment lactose with acid and gas within 48 hours Predominantly Escherichia coli  Water Purity Tests Presence of coliforms determined by: Membrane filtration method Special media Growth in biofilms Viruses and protozoans resistant to chemical disinfection Does not detect pharmaceutical drugs in water supply *Bottled water less regulated than tap water Microbiology of Food Microbes and humans compete for nutrients in food The effects of microorganisms on food can be Beneficial effects Food is fermented or otherwise chemically changed by the addition of microbes or microbial products to alter or improve flavor, taste, or texture Microbes can serve as food Detrimental effects Food poisoning or food-borne illness food spoilage Growth of microbes makes food unfit for consumption; adds undesirable flavors, appearance, and smell; destroys food value 21 Foods and Disease Methods of preserving food to prevent spoilage and growth of pathogens include: Additives, e.g., Nisin-bacteriocin produced by Lactococcus lactis-used as a food preservative Canning Must kill endospore-forming Clostridium botulinum Commercial sterilization Steam under pressure in a retort Not as rigorous as complete sterilization Drying Refrigeration 22 Radiation and Industrial Food Preservation Radiation is used to eliminate microbes from food products without disturbing chemical integrity Low doses Kill insects and inhibit sprouting Pasteurizing doses Reduce pathogens on meat and poultry High doses Sterilize or greatly lower bacteria in spices 23  High Pressure Food Preservation Pascalization Prewrapped, precooked foods submerged into pressurized water tanks Kills many pathogens and nonpathogens Preserves food color and flavor 24 Microbial Fermentation In Food products Microbes, through fermentation, can impart desirable aroma, flavor, or texture to foods (starter cultures) Bread – yeast leaven dough by giving off CO2 Beer – fermentation of wort Wine – fermentation of fruit juices Vegetable products – sauerkraut, pickles Vinegar – fermentation of plant juices Milk and dairy products – cheese, yogurt 25 Value of Fermented Goods Microbes, through fermentation, can impart desirable aroma, flavor, or texture to foods (starter cultures) What did we learn about fermentation? What are some benefits to human health? Probiotics- living microorganisms that can later occupy a host/environment to provide beneficial effects and combat pathogens Prebiotics- compounds that act as food for beneficial microbes (typically indigestible fibers) 26 Fermented Milk Products Milk is a nearly perfect medium highly susceptible to culture Cheese – After its separation from whey, the curd is rendered to produce one of the 20 major types of soft, semisoft, or hard cheese Yogurt – fermentation of milk by Lactobacillus bulgaricus and Streptococcus thermophilus Kefir, koumiss, and buttermilk 27  Microbes and Cheese Curd: made of the protein casein and formed by the action of an enzyme (rennin) and lactic acid bacteria Whey: liquid separated from curd Hard cheeses are ripened by lactic acid bacteria Soft cheeses are ripened by Penicillium fungi on the surface 28  The Art of Cheese Hard cheese ripening by lactic acid bacteria growing anaerobically Longer incubation = higher acidity and sharper taste Propinibacterium produce carbon dioxide resulting in holes Blue & Roquefort cheese ripened by Penicillium mold Aerobic fungus Blue/green discoloration is mold! 29 Nondairy fermented products Bread Bakers yeast (Saccharomyces cerevisiae) for majority of bread Sourdough bread made of a mix of different bacteria and yeast from environment Is bread a probiotic? Which is healthier, sourdough or white/whole wheat bread? Sauerkraut vs Kimchi Fermented cabbage dishes, high in antioxidants, beneficial vitamins/minerals Richest sources of probiotics, kimchi has slightly more due to added vegetables 30  Bonus- Nondairy fermented products Chocolate Critical to development of chocolate flavor Microbes unique to specific regions provide unique flavor profiles American chocolate has butyric acid added as a preservative Coffee All coffee fermented to varying degrees, depends on processing method Greater fermentation results in easier digestion Affects flavor profile but not caffeine content 31 Importance of Probiotics and Prebiotics Increased absorption of nutrients Exposure to more beneficial microbes Strengthening of gut microbiome Feeding beneficial microorganisms Maintenance of overall health History of fermented goods and beverages 32  Longevity in life long decisions Constant use of probiotics and prebiotics can contribute to overall longevity Should be introduced slowly if current diet low in fermented goods Studies show frequent ingestion of fermented goods: Improve gut health Improve immunity Contribute to anti-aging Regulate weight 33 Microbial Involvement in Food-Borne Diseases Food poisoning – diseases caused by ingesting food 2 types: Food intoxication – results from ingesting exotoxins secreted from bacterial cells growing in food Food infection – ingestion of whole microbes that target the intestine – salmonellosis, shigellosis 34 Industrial Microbiology applications Bulk production of organic compounds such as antibiotics, hormones, vitamins, acids, solvents, and enzymes Many processes involving fermentation Biotechnology Use of living organisms to produce products butanol acetone antibiotics 35 Fermentation Technology Industrial fermentation Large-scale cultivation of microbes to produce a commercial substance Uses bioreactors Primary metabolite: produced during major metabolic pathways, essential to microbe’s function Secondary metabolites: by-products of metabolism that may not be critical to microbe’s function Immobilized enzymes and microorganisms Convert a continuous flow of substance without being lost 36  Example Industrial Products Xanthan gum Thickener of products (e.g., salad dressing, shampoo) May cause intestinal gas and bloating Amino acids Microbes make only the L-isomer Glutamic acid for MSG Lysine and methionine Phenylalanine and aspartic acid in artificial sweeteners Citric acid Produced by the Aspergillus mold Enzymes Amylases-from koji, a cereal plus Aspergillus Vitamins (K, B12) 37 Industrial Products (Cont.) Pharmaceuticals Antibiotics-from Streptomycetes Isolation chip (iChip) Bacteria are grown in their natural environment Discovery of new antibiotics Vaccines Steroids-cortisone, estrogens, progesterone 38 Substance Production Steps in mass production: Introduction of microbes and sterile media into reaction chamber Fermentation Downstream processing (recovery, purification, packaging) Removal of waste Carried out aseptically and monitored for rate of flow and quality of product 39