Hey people out there. This is my very first presentation which I'm sharing with you all. hope whatever you are looking for you'll get it in there. This presentation explains various factors that affect the growth of bacteria in environment.

1. BY: DIVYA BHARDWAJ
SEMESTER 1ST
SESSION- 2017-2018
FOOD MICROBIOLOGY AND TOXICOLOGY

3.  Increase in number
of cells, not cell
size
 One cell becomes
colony of millions
of cells

4.  Control of growth is important for
◦ infection control
◦ growth of industrial and biotech organisms

5.  OXYGEN REQUIREMENT
 TEMPERATURE REQUIREMENT
 pH
 OSMOTIC PRESSURE
 LIGHT
 WATER
 CARBON DIOXIDE

6.  ON THE BASIS OF OXYGEN REQUIREMENT,
BACTERIA ARE DIVIDED INTO 4 GROUPS :
 STRICT AEROBES
 STRICT ANAEROBES
 FACULTATIVE ANAEROBES
 MICROAEROPHILIC

7.  (A) STRICT AEROBES :
BACTERIA GROWS ONLY IN PRESENCE OF
OXYGEN.
EXAMPLE: PSEUDOMONAS
 STRICT ANAEROBES:
BACTERIA GROWS ONLY IN THE ABSENCE OF
OXYGEN.
EXAMPLE :CLOSTIDIUM
 FACULTATIVE ANAEROBES :
BACTERIA WHICH CAN GROW IN PRESSENCE AS
WELL AS IN ABSENCE OF OXYGEN.
EXAMPLE:CHOLERA VIBRIO
 MICROAEROPHILIC:
BACTERIA CAN GROW IN LITTLE AMOUNT OF
OXYGEN.
EXAMPLE : STREPTOCOCCUS

8.  IN OUR BODY:
THE AEROBIC PLACES ARE : SKIN , EYE ,
MOUTH , THROAT , NOSE.
THE ANAEROBIC PLACES ARE : DEEP IN
TISSUES , LARGE INTESTINE.
THE MICROAEROBIC PLACES ARE : UPPER
PART OF STOMACH

9.  BACTERIA ARE DIVIDED INTO 3 GROUPS
ACCORDING TO TEMPERATURE REQUIREMENT:
 PSYCHROPILLIC : GROWS IN COLD TEMPERATURE
i.e. TEMPERATURE BETWEEN 4-10 DEGREE
CELCIUS.
 MESOPHILLIC : GROWS IN MODERATE
TEMPERATURE i.e. TEMPERATURE BETWEEN 15-
45 DEGREE CELCIUS.
 THERMOPHILIC : GROWS AT HIGH TEMPERATURE
i.e. TEMPERATURE BETWEEN 45-90DEGREE
CELCIUS.
 Each has a minimum, optimum, and maximum
growth temperature

11.  ON THE BASIS OF pH , BACTERIA ARE OF 3
TYPES:
 SOME GROW IN ACIDIC MEDIUM KNOWN AS
ACIDOPHILLIC . PH BETWEEN 3-6.
 SOME GROWS IN BASIC OR ALKALINE MEDIUM
KNOWN AS BASOPHILLIC OR ALKELOPHILLIC.
PH BETWEEN 8-10.
 MOST BACTERIA GROWS IN NEUTRAL PH i.e. 7
KNOWN AS NEUTROPHILES.

12.  BACTERIA VARIES IN THEIR SALT TOLERANCE :
 SOME CANNOT TOLERATE HIGH
CONCENTRATION OF SALT.
 SOME CAN TOLERATE MEDIUM
CONCENTRATION OF SALT.
 SOME CAN TOLERATE HIGH CONCENTRATION
OF SALT KNOWN AS HALOPHILES.

13.  BACTERIA PREFER TO GROW IN DARKNESS .
 PHOTOCHROMOGENIC MYCOBACTERIUM
PRODUCES PIGMENT WHEN INCUBATED IN LIGHT.
 PATHOGENIC BACTERIA, DONOT REQUIRE LIGHT
TO SURVIVE, BUT CAN BE DESTROYED BY UV
LIGHT. PHOTOSYNTHETIC BACTERIA ARE
COMPROSED OF GREEN AND PURPLE BACTERIA,
AND USE LIGHT TO PHOTOSYNTHESIZED THEIR
FOOD.THIS TYPE OF ORGANISM LIVES IN THE
ENVIRONMENT, PRIMARILY WATER.

14.  WATER IS ONE OF THE MOST ESSENTIAL
REQUIREMENTS FOR LIFE.THUS , ITS
AVAILABILITY BECOMES MOST IMPORTANT
FACTOR FOR GROWTH OF MICROORGANISMS.
 MOISTURE IS AN ESSENTIAL REQUIREMENT
FOR PHYSICAL GROWTH AS 80% OF MOISTURE
IS REQUIRED GFOR GROWTH.

15.  SMALL AMOUNT OF CO2 IS REQUIRED BY ALL
BACTERIA WHICH IS USUALLY MADE
AVAILABLE ENDOGENEOUSLY AS A RESULT OF
CELLULAR METABOLISIM OR BY THE CO2
PRESENT IN THE ATMOSPHERE.