Food Microbiology Exam Questions and Correct Solutions Rated A+ (Latest Update )

Food Microbiology Exam Questions and Correct Solutions Rated A+ (Latest Update ) Protozoa - Answers Single-celled eukaryotic organisms, many of which are motile; vertebrates. (biology based scheme of classifying microorganisms) Fungi - Answers Single or multi-celled eukaryotic organisms such as yeasts or molds. (biology based scheme of classifying microorganisms) Bacteria - Answers Single-celled diverse ubiquitous (found everywhere) organisms. (biology based scheme of classifying organisms) Viruses - Answers Simple obligate host-specific parasites (require a host to replicate), non-living? Binary Fission - Answers How bacteria reproduce; splitting in half, in ideal conditions every 20 minutes. Pathogen - Answers Organism capable of causing disease. (egocentric scheme) Aerobic - Answers When an organism requires oxygen. Anaerobic - Answers When an organism doesn't require oxygen. Bacterial Growth Curve - Answers A graph indicating the growth of a bacterial population over time Microorganism - Answers A large diverse group of free-living organisms too small to see with the naked eye. Are ubiquitous (found everywhere). Different ways microorganisms are classified - Answers The egocentric scheme and the biology based scheme. Different types of microorganisms in foods - Answers Molds, yeasts, bacteria Egocentric Scheme (types of microorganisms) - Answers Pathogenic, spoilage, beneficial Implications of different microorganisms being present - Answers Different ones can do different things; Spores - Answers Different kinds of haploid cells, reproductive cells that can develop into another organism without fusing with another cell. Why are spores important? - Answers Unit of asexual reproduction; some forms of bacteria use them to adapt for survival because they are resistant to harsh conditions. Endospores - Answers A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions Why are endospores important? - Answers Produced by some bacteria in adverse conditions to later germinate and grow into active cells. Resistant to heat, drying, and chemicals. How bacteria grow - Answers Usually binary fission (reproduction by splitting in half) Hurdle Technology - Answers Using a number of factors that control growth of microorganisms together. Each hurdle insufficient by itself, but together can prevent microbial growth. How is Hurdle Technology applied to foods? - Answers Uses a combination of techniques to kill pathogens in food that would harm us when ingested. Spoilage - Answers Organisms responsible for deletrious alterations in a food's appearance, texture, or flavor. (egocentric scheme) Beneficial - Answers Organisms involved in preserving foodstuffs via fermentation and probiotics Order of bacterial growth curve - Answers lag --- log ---- stationary ---- decline Significance of 4.6? - Answers Bacteria typically do not grow below pH 4.6. (most foods at pH of 5-7) Water Activity (Aw) effect on enzymes? - Answers Most enzymes have an optimal Aw 0.9. However, very complex Extrinsic factors of microbial growth? - Answers Temperature, level of oxygen, and relative humidity Intrinsic factors of microbial growth? - Answers Acidity, aw, oxidative state, nutrient content, naturally-occurring inhibitors, biological structure. Foodborn pathogens responsible for the greatest number of deaths. - Answers 1) Salmonella 2) Toxoplasma gondii 3) Listeria monocytogenes 4) Norovirus 5) Campylbacter spp. What is the U.S government doing to try to control foodborn illnesses? - Answers - Food Net (CDC surveillance network for foodborn illness in 10 states) identifies specific outbreaks/associated foods, implevents prevention and control measures). -Pulse Net (CDC run network of public health labs to identify microorganisms, detect and contain) uses molecular biology techniques. Foodborn infections - Answers You ingest the live organism and it colonizes your intestinal tract and damages/invades it. (salmonella, parasites) Foodborne intoxications - Answers The organism produces a toxin in the food, you eat the food, and the toxin makes you ill. (Staphylococcus aureus, Clostridium botulinum) toxicoinfections - Answers You ingest the live organism, organism provides a toxin in your digestive tract, toxin makes you ill; non-invasive! (Clostridium perfringens, STEC) Foodborn disease most common pathogens - Answers 1) Norovirus 2) Salmonella 3) Clostridium perfringens 4)Campylbacter spp. 5) Staphylococcus aureus Foodborn disease pathogens resulting in hospitalization - Answers 1) Salmonella 2) Norovirus 3) Campylbacter spp. 4) Toxoplasma gondii 5) Eschichia coli (STEC) Infectious Dose - Answers The quantity of pathogen organisms require to cause infection in a host Infectious Carrier - Answers those who have a low-level infection with a disease, but without symptoms. Can simply be prior to the onset of disease of a stable low-level infection. Carriers can transmit the disease to to others. (Typhoid Mary) Fecal-Oral Transmission - Answers When infectious agents present in the feces of one individual are swallowed by another individual (human to human); water not uncommon intermediate vehicle Salmonellosis - Answers Salmonella from digestive tract; doesn't form spores. poultry, complex foods, produce, red meat, raw eggs nausea, vomiting, diarrhea (12-24 hours) Reiter's syndrome (joint pain, eye irritation, painful urination)