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Food Micro Lectue 7
Food Micro Midterm 2
| What are the three types of microbial detection testing? | Investigational testing, acceptance testing, professional reasons |
| Investigational testing is used to determine if a _____ is present. | hazard |
| Investigational testing verifies that ____ ____ have been met in HACCP. | critical limits |
| Challenge testing is a part of _____ testing. | investigational |
| ______ testing must comply with legal or contractual requirements. | Acceptance |
| _____ testing is useful in determining the quality of incoming materials and purchase specifications. | Acceptance |
| Professional reasons usually involve _____ studies to establish methodology. | collaborative |
| In environmental sampling, one must be aware of ____ cells. | VBNC (viable but non culturable cells) |
| What are the three types of diluents used for quantitative detection? | Buffered peptone water, 0.1% peptone water, physiological saline |
| How is the most probable number (MPN) technique advantageous over plate count? | Can detect a lower number of bacteria. |
| What are the cons to MPN? | Not as accurate, needs a lot of glassware. |
| What is the sensitivity of direct microscopic count? | 1 cell/field (1000x magnification) ~1E6/mL |
| What are the cons to DMC? | Cannot distinguish between viable and dead cells; un-uniformally stained. |
| Describe the direct epifluorescent filter technique (DEFT). | Filtration of "stomached" food suspensions through nylon filters; used widely in the dairy industry; captures viable cells only. |
| Plaque forming units are commonly used in the detection of _____. | viruses |
| What are two rapid methods of cell detection? | Measure of ATP, flow cytometry (particle enumeration). |
| _____ detection can be done through microbial enrichment. | Qualitative |
| T or F: Sub-lethally injured bacteria will grow on selective media. | False |
| How can the number of injured microorganisms be counted? | Grow on non-selective and selective media and find the difference between them. |
| What are the three criterion for media selection? | productivity (ability to support growth), selectivity (discourage growth of competitors), electivity (easy differentiation between cells) |
| Name three types of media which can be used for aerobic plate count. | brain heart infusion, trypticase soy agar, plate count agar |
| Total Plate Count and Viable Plate Count are ________ media. | non-selective. |
| Yeast and mold will grow on _____ _____ agar. | rose bengal |
| How can bacteria be identified based on structure? | size, shape, extra-cellular characters, differential staining |
| Name three ways to identify bacteria biochemically. | Growth media, serological tests, protein analysis. |
| Define serotype. | Groups within a single species of microorganism with distinctive surface structures. |
| How are Salmonella serotyped? | By a pattern of O antigens present. |
| What does ELIA stand for and how does it work? | Enzyme-Linked ImmunoSorbant Assay; a plate-based technique which can detect substances such as peptides, proteins, antibodies, etc. |
| What are three genomic methods of identifying bacteria? | PCR, DNA fingerprinting, sequencing. |
| Define whole genome sequencing. | Determining the complete DNA sequence of an organism's genome at one time. |
| ____ are a form of global gene expression profiling. | Microarrays |
| RT-PCR uses ______ in order to detect levels of ____ ____. | fluorophores, gene expression |
| What does PFGE stand for? | Pulsed-Field Gel Electrophoresis |