298 78 6MB
English Pages [211]
Table of contents :
Cover
Half Title
Title
Copyright
Preface
Contents
Chapter 1: Microbiology Laboratory Orientation
Chapter 2: Sterilization and Disinfection
Chapter 3: Media Preparation
Chapter 4: Microscope
Chapter 5: Aseptic Culture Techniques
Chapter 6: Isolating Bacteria: Pure Culture Technique
Chapter 7: Enumeration of Bacteria
Chapter 8: Colony Description
Chapter 9: Microscopic Examination of Living Bacteria
Chapter 10: Antibiotic Sensitivity Testing
Chapter 11: Biochemical Tests for Identification of Bacteria
Chapter 12: Isolation of Moulds
Chapter 13: Enumeration of Yeasts and Moulds in Foods
Chapter 14: Microscopic Examination of Yeast and Moulds
Chapter 15: Microbiological Examination ofVanous Food Materials
Chapter 16: Microbial Examination of Canned Foods
Chapter 17: Water Microbiology
Chapter 18: Isolation and Identification of Common Food-Borne Pathogens
Chapter 19: Microbial Standards for Different Foods and Drinking Water
Chapter 20: Chemical Food Preservatives
Chapter 21: Heat Preservation of Microorganisms
Chapter 22: Disinfectants and Antiseptics
Chapter 23: Preservation of Cultures
Chapter 24: Food Fermentation
Chapter 25: Good Manufacturing Practice, Codex Alimentarius and HACCP
Chapter 26: Media and Reagents
Index
Backcover
©Copyright 2020 I.K. International Pvt. Ltd., New Delhi-110002. This book may not be duplicated in any way without the express written consent of the publisher, except in the form of brief excerpts or quotations for the purposes of review. The information contained herein is for the personal use of the reader and may not be incorporated in any commercial programs, other books, databases, or any kind of software without written consent of the publisher. Making copies of this book or any portion for any purpose other than your own is a violation of copyright laws. Limits of Liability/disclaimer of Warranty: The author and publisher have used their best efforts in preparing this book. The author make no representation or warranties with respect to the accuracy or completeness of the contents of this book, and specifically disclaim any implied warranties of merchantability or fitness of any particular purpose. There are no warranties which extend beyond the descriptions contained in this paragraph. No warranty may be created or extended by sales representatives or written sales materials. The accuracy and completeness of the information provided herein and the opinions stated herein are not guaranteed or warranted to produce any particulars results, and the advice and strategies contained herein may not be suitable for every individual. Neither Dreamtech Press nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. Trademarks: All brand names and product names used in this book are trademarks, registered trademarks, or trade names of their respective holders. Dreamtech Press is not associated with any product or vendor mentioned in this book. ISBN: 978-93-89633-02-3 EISBN: 978-93-89976-57-1
Edition: 2020
Preface This book serves as a general laboratory guide for individuals in quality control, quality assurance, sanitation and food production. In essence this book deals with basic and applied food microbiology and food safety. The book provides a review of basic microbiological techniques – media preparation, aseptic techniques, dilution plating etc. – followed by analytical methods and advanced tests for food-borne microbes (including pathogens). This is a very useful book for food industry personnel with little or no background in microbiology or who need a refresher course in basic microbiological principles and laboratory techniques. It reviews basic microbiology techniques to evaluate the microbiota of various foods and enumerate indicator microorganisms. It emphasizes conventional cultural techniques. It also focuses on procedures for detecting pathogens in food, offering students the opportunity to practise cultural and biochemical methods. The final section discusses beneficial microorganisms and their role in food fermentation, concentrating on lactic acid bacteria, acetic acid bacteria and yeast. It provides an ideal text companion for an undergraduate or graduate laboratory course, offering the faculty an authoritative frame of reference for their own supplementary materials and to the food processing industry personnel, government and private organizations linked with food processing and microbial quality of the processed product. The book is an essential text for microbiologists working in the food industry, quality assurance personnel and academic researchers. In conclusion, our attempt is to provide knowledge of laboratory food microbiology. Our hope is that this volume will be helpful for any interested reader, inspiring and supporting the research efforts today necessary in the field and laboratory research work as well. Neelima Garg K. L. Garg K. G. Mukerji
Exhaust HEPA filter
Rear plenum Supply HEPA filter
Sash Front opening
HEPA-filtered air Room air
Contaminated air
Blower
Stab or Deep
Streaked Petri dish Slant
Oculars
Revolving nosepiece Arm
Multiple objectives Iris diaphragm lever
Stage Stage manipulator jknobs Fine adjustment knob
Condenser Coarse Adjustment knob Light source Base Power switch
Eye Final image Eyepiece Projector lens
Objective Specimen
Condenser lens
Light
Fine scale, enlarged 0.11 mm
1.0 mm
0.7
Scale is divided into 0.1 mm units Last 0.2 mm is divided into units of 0.01 mm
Diameter = 0.11 + 0.7 + 1.0 = 1.81 mm
Virtual Source First condenser lens Condenser aperture Second condenser lens Objective aperture Scan coils Objective lens
Sample
Virtual Source First condenser lens
Second condenser lens Condenser aperture
Sample Objective lens Objective aperture Selected area aperture
First intermediate lens Second intermediate lens Projector lens
Main screen (phosphor)
1 2
4 3
Colonies separated by streak plate technique
Streak plate technique
Spread plate technique
Colonies separated by spread plate technique
Coccus Diplococcus
Bacillus
Streptococcus
Staphylococcus
Spirillum
Vibrio Micrococcus
Arborescent
Effuse
Echinulate
Rhizoidal
Beaded
Filiform
Colony Shape
Edge (margin) of colony
Punctiform Entire Circular Undulate Rhizoid
Irregular Lobed
Filamentous Filamentous colony
Curled (Concentric)
Common colony shapes Round
Punctiform
Filamentous
Irregular
(under 1 mm diameter)
Common colony margins Smooth (entire)
Curled
Wavy
Lobate
Filamentous
Common colony surface characteristics Smooth
Wrinkled
Concentric
Contoured
Common colony elevations (seen from side) Raised
Convex
GRAM +
GRAM – Peptidoglycan Peptidoglycan
Membrane Membrane
Periplasm Lipopolysaccharide and protein
Gram-positive rod
e.g. Bacillus cereus
Gram-positive coccus
e.g. Staphylococcus epidermidis
Lipoarabinomannan Mycollc acid Arabinogalactan Peptidoglycan Mannophosphositide
Cytoplasmic membrane
Coat
DNA Spore
a. Place a second slide on top of the first as shown
b. While maintaining contact with the bottom slide, move the top slide to contact the drop. It will spread by capillary action.
c. Maintain contact with the bottom slide and move the top slide in one to produce the smear.
Depression area Vaseline ring
I
Hanging-drop slide
Inoculation needle
II Drop of bacterial culture
Coverslip
Vaseline
Cover slip with drop of bacterial culture
Hanging drop preparation
III
If growth occurs outside this ring, the organism is sensitive to the antibiotic
} }
AM 10
If growth occurs within this ring, the organism is resistant to the antibiotic
If growth occurs within this ring, the organism has intermediate resistance sensitivity
Starch hydrolysis positive
Starch hydrolysis negative
Production
Acid production
Acid
→
→ →
Urease positive
Urease negative
MR test positive
MR test negative
Indole negative
Indole positive
VP negative
VP positive
Citrate utilization positive
Citrate utilization negative
A
B
D
C
′′ ′′ ′′ ′′
6
1,000,000
5
4
10,000
3
1,000
D-value 2
100
1
10 1 0
10
20
30
40
Time (min.)
50
60
70
Log 10 of living bacteria
Numbers of living bacteria
100,000
D-value (minutes)
30
3 Z-value (100–90 = 10)
0.3
90
100
110
Temperature (°C)
Destroyed 30
D-value (minutes)
Pathogen (Z = 10)
Vitamin (Z = 25) 3
0.3
High temperatures and short times
Not destroyed
90
0.0
110
Temperature (°C)
→
α