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Diet and Food Production
Microorganisms can cause diseases, and at the same time, a lot of them are useful to us
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They can feed on the same food as us
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Eg like bread, the spots that form, the
fungi that feed on it
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They are also important for food production and medicine, and the ones present in mouth
and stomach, help with digestion
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They secrete enzymes to the food and
the enzymes can digest the food materials
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The enzymes can hydrolase the substances in the
food, so the microorganisms a can easily absorb it
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This
changes the appearance of the food, smell and the taste, so if you eat that, then you will have
problems
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They produce toxins as waste products
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Preventing spoilage:
How to stop growth of bacterium:
In things like squash and syrup, the concentration of sugar is very high, so there won’t be any
microorganisms there
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Low temperature (minus) – fridge- the metabolic relations won’t take place in their body
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Freezer: where temp is -10 degrees or less
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The
organism can’t attack food and survive there
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Sometimes
they are not killed in the freezer
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On
return of favourable conditions, they can be active again
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Fruits can be freeze dried: involves freezing the food in a vacuum, to remove all the
moisture, and sealing food in an airtight container, preventing the water from becoming ice
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This does less damage
to the cells in the food as no ice crystals are formed and could pierce and break the plasma
membrane
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It can be stored
for a long period of time
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It can
destroy micros, or at least prevent growth
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We do this by salting
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The
salting method
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This greatly changes the flavour of the food, but many people enjoy it, eg like ham, bacon
etc
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If enzymes are in an
acidic solution, eg: vinegar, ethanoic acid (solution with low pH), often used for food
preservation, preventing the growth of micros
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Some bacteria can still survive the heat, producing resistant spores, that’s their
speciality
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But most of them would die
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Cooking food until piping hot, should kill almost all the micros,
and make it safe to eat
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Eg: if you don’t boil milk in a proper way, it can get
spoiled very quickly
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This milk can only be kept for a few days, as not
all bacteria have been killed, before it goes off
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Then it is sealed in air tight contained
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Irradiation: ionising radiation
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Gamma radiation is the type that is used for food treatment
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Speciality is that it can be used for food preservation
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Radiation
can kill most, and has very little effect on the food itself
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Some dislike this idea as it can cause some health problems
when you use it continuously, as the radiation can change some chemicals to change into
others
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Due to biotechnology crops have been produced
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Lifestyle and food habits have caused problems- white patches of skin, etc
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Microorganisms for food production:
They have used for food production for thousands of years
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Yogurt and cheese can be kept longer than milk
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Recently a food called mycoprotein,
developed from fungus called Fusarium
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The main mycoprotein on sale is Quorn TM
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The culture medium contains glucose, which is
usually obtained from starch which has been hydrolysed by enzymes
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Fermentation is respiration without air, and by
using this fermenter you make mycoprotein
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(Like manures in
rainy reason)
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When the atmospheric nitrogen is converted into nitrate, the
plants can easily absorb it
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No stirring is used as the fungus is made of long threadlike hyphae (fungal body) and the
movement may cause damage to the fungal mycelium
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Enzymes are added to break
this down so mycoprotein makes an excellent food, rich in protein and low in fat
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It hasn’t caught as the manufactures thought it would
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So it is used as a meat substitute for vegetarians
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Many
more people die from heart and gas exchange system diseases
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Tobacco smoke contains many different chemicals; tar (which can cause cancer), nicotine (addictive
substance that is addictive and affects brain and other parts of the nervous system and the
cardiovascular system), CO (gas produced from incomplete oxidation of some substances in tobaccoreducing O2 carrying capacity of the blood as haem combine with CO more than O2)
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Particulates are thin particles, mostly of carbon that cause
irritation in the lungs and airways
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Compounds found in cig smokedirect cause for lung diseases, increase the risk of developing CHD, and develop the risk of having a
stroke
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