FDE305 Food Microbiology Laboratory 2024 PDF

FDE305 - FOOD MICROBIOLOGY LABORATORY Microscopic Examination of Microorganisms The Use and the Care of Microscope & Simple Staining  Objectives To know the parts and respective functions of the microscope To use microscope effectively To prepare and stain bacterial smears To be profi...

FDE305 - FOOD MICROBIOLOGY LABORATORY Microscopic Examination of Microorganisms The Use and the Care of Microscope & Simple Staining  Objectives To know the parts and respective functions of the microscope To use microscope effectively To prepare and stain bacterial smears To be proficient in locating and examining stained bacterial smears To be able to distinguish basic bacterial shapes Introduction Cytology means the study of cells, concerned with the cell and its parts. The stuctures studied in cytology are microscopic and they are not clear cut. We use differential staining as a principal tool in cytology in which two or more reagents are applied. Simple staining is the application of a single stain or reagent. Introduction Application of certain chemicals to different substances produces color reactions specific for the treated substances. Cellular proteins and amino acids can ionize either as an acid or as a base (amphoteric substances) Proteins involved in most of the staining reactions. In order to react successfully, a biological stain must display a color and be able to ionize either as an acid or as a base  Introduction Preperation of cells for observation is important in cytological studies. Sufficiently thin layer of cells are prepared on microscope slide so it allows light pass through. Smear preperation: If made from broth culture, suspension applied directly to slide without dilution. If made from solid media, very small portion of growth should be taken and should be emulsified in a drop of water. To make sure the cells stick to the slide and not be washed off during stainig fixation must be done. Fixation stops enzymatic activity that can destroy the material in the cell if the cell diesdies.  MICROSCOPIC EXAMINATION OF MICROORGANISMS Care of the Microscope Simple Staining  CARE OF THE MICROSCOPE Microscope should be in upright position since the ocular could fall. Keep the microscope at least 15 cm away from the edge of the table. Do not handle the lenses with your fingers. Do not tamper with any components of the instrument. Do not allow chemical come into contact with microscope. Remove immersion oil with lens paper. Always be certain that the low-power objective in the working position, that is in line with the body tube before putting the microscope away. Be certain that to cover, covers the entire microscope while not in use.  SIMPLE STAINING References ÖKMEN, Z. A., & BOZOĞLU, F. (1995). Food Microbiology Laboratory Book (pp. 1-16). Ankara, Turkey: Food Engineering Department, Middle East Technical University. Sharma, B. (2022). Types of staining techniques in Microbiology. In My Biology Dictionary. https://mybiologydictionary.com/types-of- staining-techniques-in-microbiology/