Bacteria
are single celled organisms, each bacteria cell is self-sufficient and so able
to live independently. Bacteria come in range variety of shapes and are
impossible to see without a microscope. And when they grow, they increase in
number not in size. Although some bacteria are beneficial such is those used to
make fermented dairy and meat products. Which are among microorganism that
causes food poisoning?
are single celled organisms, each bacteria cell is self-sufficient and so able
to live independently. Bacteria come in range variety of shapes and are
impossible to see without a microscope. And when they grow, they increase in
number not in size. Although some bacteria are beneficial such is those used to
make fermented dairy and meat products. Which are among microorganism that
causes food poisoning?
For
them to grow and multiply, they need certain conditions. Conditions that are
favourable for their growth and multiplication include:
them to grow and multiply, they need certain conditions. Conditions that are
favourable for their growth and multiplication include:
1.
Moisture (water)
Moisture (water)
2.
Air (oxygen)
Air (oxygen)
3.
Temperature
Temperature
4.
Food/nutrient
Food/nutrient
5.
Time
Time
6.
PH (alkaline and acidic).
PH (alkaline and acidic).
1. Moisture (Water)
Bacteria
need water to dissolve the food they use for energy and food to get into the
cells which is used for many chemical reactions necessary for life and growth
and allows waste product escape.
need water to dissolve the food they use for energy and food to get into the
cells which is used for many chemical reactions necessary for life and growth
and allows waste product escape.
2. Air (Oxygen)
Most
bacteria require oxygen to grow (aerobes) e.g. salmonella and staphylococci
while others can only grow in the absence of oxygen (anaerobes) e.g.
clostridium botulinum and clostridium perfringens. However, many bacteria grow
under either condition, they are called facultative anaerobes.
bacteria require oxygen to grow (aerobes) e.g. salmonella and staphylococci
while others can only grow in the absence of oxygen (anaerobes) e.g.
clostridium botulinum and clostridium perfringens. However, many bacteria grow
under either condition, they are called facultative anaerobes.
3. Temperature
Bacteria
in general are capable of growing under a wide range of temperature. That is,
each kind of bacteria has temperature in which its activity is greater and is
classified according to the temperature at which they grow.
in general are capable of growing under a wide range of temperature. That is,
each kind of bacteria has temperature in which its activity is greater and is
classified according to the temperature at which they grow.
i.
Psychrophilic Bacteria: these are capable of growing at 32oF-45oF
but their optimum is from 68oF-86oF. They cause spoilage
in food stored under refrigeration. E.g. yersinia and listeria.
Psychrophilic Bacteria: these are capable of growing at 32oF-45oF
but their optimum is from 68oF-86oF. They cause spoilage
in food stored under refrigeration. E.g. yersinia and listeria.
ii.
Mesophilic Bacteria: They are capable of growing at 60oF-110oF
(37oC) which includes body temperature. They cause food poisoning
and are responsible for much food spoilage.
Mesophilic Bacteria: They are capable of growing at 60oF-110oF
(37oC) which includes body temperature. They cause food poisoning
and are responsible for much food spoilage.
iii.
Thermophilic Bacteria: These microorganisms grow at higher
temperature such as 110oF-150oF (60oC). This
group of bacteria is troublesome in food canning.
Thermophilic Bacteria: These microorganisms grow at higher
temperature such as 110oF-150oF (60oC). This
group of bacteria is troublesome in food canning.
4. Food/Nutrient
All
bacteria require energy to live and grow. Energy sources such as sugar, starch,
protein, fats and other compounds provide the nutrient. Unfortunately, the food
most often preferred by human being are those which food spoilage organism
thrive on most such as milk, meat, eggs and other products. Hence, protein
based foods are the most suitable media for bacteria metabolism so long as
environmental condition are favourable.
bacteria require energy to live and grow. Energy sources such as sugar, starch,
protein, fats and other compounds provide the nutrient. Unfortunately, the food
most often preferred by human being are those which food spoilage organism
thrive on most such as milk, meat, eggs and other products. Hence, protein
based foods are the most suitable media for bacteria metabolism so long as
environmental condition are favourable.
5. Time
Time
is needed for bacteria to rapidly multiply, they need certain time to grow
sufficient in order to cause illness in man (under ideal condition, one
bacterium divides every 20-30 minutes, and that beyond 6 hours, millions of
bacteria would have been produces.
is needed for bacteria to rapidly multiply, they need certain time to grow
sufficient in order to cause illness in man (under ideal condition, one
bacterium divides every 20-30 minutes, and that beyond 6 hours, millions of
bacteria would have been produces.
6. PH
PH
is measure of acid or alkali in a product. It is indicated in a scale from
0-14, with seven (7) being neutral. If the PH value is below 7, the
food is classified as acidic, if it is above 7; the food is classified as
alkaline.
is measure of acid or alkali in a product. It is indicated in a scale from
0-14, with seven (7) being neutral. If the PH value is below 7, the
food is classified as acidic, if it is above 7; the food is classified as
alkaline.
Most
bacteria grow at neutral PH, but many can reproduce in a PH
range from 4.5-10.0.
bacteria grow at neutral PH, but many can reproduce in a PH
range from 4.5-10.0.