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Food Micro Lecture 8
Food Micro Midterm 2
T or F: Sporeformers are usually gram-positive rods. | True |
T or F: Sporeformers can produce multiple spores per cell. | False |
Endospores can survive long periods of time without _____. | nutrients |
Name four things which endospores are resistant to. | UV radiation, dessication, high temperatures, chemical disinfectants. |
T or F: Endospores can be destroyed by autoclaving or canning. | True |
Describe tyndalization. | An indirect method of destroying spores which puts them in their vegetative state for easier manipulation. |
Prolonged exposure to _____ will kill most endospores. | irradiation |
What are the three structural components of endospores? | core, core wall, spore coat |
The endospore _____ is dehydrated and contains all important cellular components. | core |
The endospore _____ _____contains the inner membrane which becomes vegetative cell membrane. | core wall |
The endospore _____ _____ is composed of layers of proteins for additional resistance. | spore coat |
What are the stages of the spore cycle? | Germination, outgrowth, sporulation, dormancy, activation |
What can trigger sporulation? | Environmental conditions such as temperature, pH, or availability of nutrients. |
What can trigger spore activation? | Sublethal heat, radiation, high pressure, pH extremes. |
T or F: Spore activation is irreversible. | False |
T or F: Spore germination is irreversible. | True |
What can trigger spore germination? | Low pH, temperature, lysozyme, nutrients |
When is spore outgrowth terminated? | When one vegetative cell emerges from the spore. |
What occurs during spore outgrowth? | Synthesis of cellular components, repair of the spore, swelling due to nutrient uptake. |
What occurs during spore germination? | The core is hydrated, Ca and DPA are excreted, spore loses resistance. |
T or F: Ungerminated spores can still cause human disease. | False |
____ ____ is used in food processing to inactivate all pathogenic spores. | High heat |
What are the four types of sporeforming pathogens? | B. anthracis, B. cereus, C.botulinum, C. perfringens |
B. anthracis is found mostly is _____ foods. | animal |
What are the three ways which anthrax can occur? | Inhalation, cutaneous, gastrointestinal |
Where in the cell does the endospore form in B. cereus? | middle |
B. cereus infection when experiencing diarrhea is considered _____. | enteric |
B. cereus when experiencing vomiting is considered _____. | emetic |
The B.cereus enteric toxin is produced where? | In the small intestine. |
The B. cereus emetic toxin is produced where? | In the food itself. |
T or F: B. cereus must be temperature abused to allow for spore growth. | True |
What type of foods carry enteric B. cereus? | Meats, milk products, vegetables, casseroles |
What type of foods carry enteric B. cereus? | Starchy foods |
What are the oxygen requirements for B. cereus? | Aerboic |
What are the oxygen requirements for Clostridium spp? | Anaerobic |
C. perfringens require ____ ____ for growth. | amino acids |
T or F: C. perfringens is considered an enterotoxin. | True |
Where can C. perfringens be found? | Soil, dust, intestines of animals. |
Which of the seven types of C. botulinum affect humans? | A, B, E, F |
C. botulinum is made dangerous by the ______ ______. | botulinum neurotoxin |
What are the two main objectives in controlling C. botulinum in food? | Destroy all the spores in the product; Prevent spore germination, growth, and toxin production during extended storage. |
Define toxico-infection. | When viable vegetative cells are ingested, they release toxins in the gut. |
C. perfringens and B. cereus act via ____ ____. | toxico-infection |
Staphlococcal food poisoning and botulism act via _____. | intoxication |
Define bacterial toxin. | A soluble substance that alters the normal metabolism of the hot cells with deleterious effects on the host. |
T or F: Exotoxins are non-specific. | False |
T or F: Endotoxins are less potent than exotoxins. | True |