Agricultural Microbiology Practical MCQ Exam - MICR20010 PDF

MICR20010 Agricultural Microbiology Dr. Tadhg Ó Cróinín  Practical MCQ Exam Practical Online MCQ exam is on this Friday Nov 22nd from 2-3pm Please try the sample questions under quiz tab in brightspace and note instructions in e-mail to follow. Separate e-mail for DSS studen...

MICR20010 Agricultural Microbiology Dr. Tadhg Ó Cróinín  Practical MCQ Exam Practical Online MCQ exam is on this Friday Nov 22nd from 2-3pm Please try the sample questions under quiz tab in brightspace and note instructions in e-mail to follow. Separate e-mail for DSS students. Sample MCQ questions for final exam in RDS also available on Brightspace.  MICR20010 - remaining lectures Lecture 10 – Microorganisms and Disease Lecture 11 – The Immune System Lecture 12 - Pathogenic Bacteria Lecture 13 – Pathogenic Fungi and Viruses Lecture 14 – Antibiotic Resistant Microorganisms Lecture 15 – Microbiology in the Food Industry – The Fungi Lecture 16 – Microbiology in the Food Industry - Fermentations Lecture 17 – The Nitrogen Cycle Single cell protein + Microbial Biomass  Single Cell Protein Began in WW2 to produce protein cheaply - S. cerevisiae and Candida utilis. Rapid development in 1960s and 1970s with emergence of phrase SCP. Most used as animal feed rather than human consumption Production of yeast from whey or Quorn production Protein increase in global population…search for alternative protein source Single cell protein (SCP) – SCP= microbial cells grown and harvested for animal/ human food WHY SCP? Choice of m/os due to rapid growth high protein content use cheap organic substrates to grow Protein production by cattle + yeast bullock.. Wt 500Kg..yields 0.4kg protein/24h Yeast.. Wt 500kg..yields> 50,000kg/24h The Fermentor Applications for Yeast in the Food Industry Production of Yeast Biomass Key to high yield is aeration – avoid fermentation Cheap media –historically media from cereal grains, now predominantly molasses. Gradual scale up of culture from bench-top to fermentor! Special feeding regime to avoid fermentation (fed batch) Production of Yeast Biomass Ripening stage to encourage production of trehalose and reduce protein production Centrifugal separators before washing, drying and packing Maximising Biomass is the key aim Yeast Production What makes a good Bakers Yeast? High growth rates Good storage characteristics including cryotolerance Osmotolerance – to function within dough Rapid utilization of maltose – main sugar of dough High Glycolytic activity and “gassing power” SCP-can be produced from – Algae..spirulina – fungi… – bacteria Biomass can be produced by – submerged fermentation – solid state fermentation – After fermentation: biomass is harvested, washed, disrupted, and protein extracted Substrates for micro-organism production: Algae: use CO2 + sunlight Fungi: cheap wastes supply C + N source Bacteria: wastes or by-products of industrial processes Substrates for micro-organism production: molasses from sugar manufacture/ starch hydrolysis spent sulphite liquor acid hydrolysates of wood Agricultural wastes methane methanol +ethanol gas oil Nutritive value of micro-organism Algae: rich in proteins, fats + vitamins A,B,C,D +E 40-60% protein 7% mineral Fungi: B-complex group of vit. aa content of A.niger: well balanced Yeast: have thiamine, riboflavin, biotin Bacterial SCP: high in protein + certain essential aa methionine: 2.2-3% > algal (1.4-2.6%) and fungi (2.5-1.8%) SCP: limitations for use Algal SCP cell wall- cellulytic component cannot be digested by humans..walls must be pre-digested (not for cattle feed) production is weather dependent Fungal SCP: Aspergillus parasiticus, A.flavous:.. Mycotoxins Bacterial SCP use is limited to cost harvesting can be expensive bacterial cells have high nucleic acid content (uric acid accumulates in body..kidney stones + gout) SCP in solving protein malnutrition source of human + animal feeds m/o’s accepted for human consumption: – Saccharmyces cerevisiae – Candida utilis – Chlorella spp. SCP example: Quorn myco-protein Fusarium graminearum Schwabe A3/5-used in UK Quorn myco-protein for humans meat alternative: – taste,textures of meat products (vegi alternative) myco-protein: cells grown on glucose harvested High nutritional value once produced it is mixed with a binder to give desired shape + flavour  Indirect Fermentations M/O in food production direct direct Mushrooms Single cell protein Mushrooms Mushrooms: Filamentous fungi that form fruiting bodies known as mushrooms ~12,000 fungal species (~2000 have some edibility) – Agaricus bisporus (button mushroom) – Lentinus edodes – Pleurotus spp (oyster mushroom)  Mushrooms A long tradition of use of mushrooms as a food source (or narcotic) Very cheap to produce and can readily be grown on plant waste Excellent source of protein Easy to harvest the fruiting bodies Agaricus Bisporis  Mushroom production Preparation of inoculum in liquid culture Preparation of beds - composting Inoculation into compost and mycelial growth at 25oC for 2-3 weeks Application of casing of peat (covering layer) Fruiting body production in about four flushes (successive crops) over a period of 4-6 weeks. Lentinus edulus Other benefits of mushrooms: Medicinal mushrooms Extracts of species from genera: Auricularia Flammulina, Ganoderma, Hericium And more Employed medicinally In medicine: Immunomodulators – Some have anti-cancer action Source of rare minerals and amino acids – Copper, zinc, selenium, iron. Problems of fungi: Mycotoxins Mycotoxins secondary metabolite of fungi: – mycotoxicoses in animals + humans – some linked with certain types of cancer – present in mycelium and in some cases in the spores of filamentous fungi – not all are harmful In human food chain problems with – Aspergillus, Penicillium: contaminate foods during drying and storage – Fusarium: plant pathogen- produces mycotoxin before/ immediately after harvesting Alflatoxins: first discovered in 1960 – 100,000 turkey poults died suddenly in England – 14,000 ducklings – 9 out breaks in calves – common factor: Brazilian peanut meal in animal feed. Produced mainly by: Aspergillus flavus, A.parasiticus Alflatoxins: 4 main alflatoxins: B1,B2,G1, G2 (&M1) difuranocoumarin derivatives-B &G = Blue (B) & green (G) fluorescent colours produced under UV light Aflatoxins found in: maize, animal products, peanuts.  M1= hydroxylated derivative of B1 M2=.... of B2 – M1 & 2 – formed + excreted in milk of lactating animals – less toxic than B1 or 2 – BUT M1= toxic & carcinogenic  Next Monday on MICR20010 Microbiology in the Food Industry – Alcohol, Dairy Industry and Vinegar Remember Online Practical MCQ exam on Friday at 2pm!