Transcript Food Science and Biotechnology

Food Science and
Biotechnology
Biotechnology II
COMPETENCY: 13.00
Examine techniques and
biological processes in food
science related to
biotechnology.
OBJECTIVE: 13.01
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Explore food borne pathogens and
spoilage organisms in relation to
agricultural biotechnology.
Common Food Bourne Pathogens
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1. Salmonella enteriditus
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A common bacteria responsible for severe cases of food
poisoning and digestive ailments in humans.
Often transmitted through contact with infected animals
or ingestion of raw or undercooked egg that has
contacted a contaminated shell.
2. Campylobacter jejuni
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Common bacterial pathogen found in undercooked
meats, unpasteurized milk, and other contaminated
foods.
Responsible for more than 10% of all instances of
diarrhea in the US.
Salmonella enteriditus
Source: http://www.magma.ca/~pavel/science/Salmonella.htm
Campylobacter jejuni
Scanning electron microscope image of Campylobacter jejuni, illustrating its corkscrew
appearance and bipolar flagella. Source: Virginia-Maryland Regional College of Veterinary
Medicine, Blacksburg, Virginia.
Common Food Bourne Pathogens
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3. Bacterial contaminants usually spread by
physical contact or ingestion of a
contaminated liquid or solid.
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4. Fungi
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A variety of fungi are used in the production of
foods, including cheeses and yogurt.
Other fungi are contaminants, some even toxic.
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Often appear on breads with high moisture and
sugar content, citrus fruits and grains.
Usually spread by airborne spores as opposed.
Often appear as fuzzy, blue growth in canned corn or
fuzzy, white spots on bread.
Preventing Food Bourne Pathogens
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1. Poultry & Other Meats
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Meat should be heated in an oven to 74°C for at
least 15 seconds.
2. The optimal temperature range for the
growth of harmful bacteria in foods is
between 4°C – 60°C.
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Low temperatures usually cause dormancy in
bacteria.
High temperatures can deactivate or even destroy
bacteria.
OBJECTIVE: 13.02

Summarize enzyme activities and
fermentation processes that are
useful in the food processing
industry.
Enzyme Activities
1. Enzymes are specialized proteins that act as
catalysts to speed up chemical reactions in
organisms or compounds.
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Enzymes are incredibly important in processes as
diverse as digestion, respiration, and
fermentation.
It is enzymes that convert lactose in milk during
the process of making yogurt that allows lactose
intolerant people to consume the product.
2. There are 26 enzymes almost always
ending in the suffix “ase”.
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Important enzymes include amylase, protease,
and lipase.
Fermentation Processes
1. Fermentation- the anaerobic conversion of
sugars in plant materials to simple chemical
compounds.
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Alcoholic fermentation the most common and
important in biotechnology.
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The conversion of sugars during the breaking down
of plant materials into Carbon Dioxide and Ethanol.
Carried out by yeast.
2. The study of fermentation processes used
in bread making, wine making and the
formation of other food products is known
as Zymology.
Yeast
Important microorganisms in the
production of several types of foods.
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Yeast are NOT BACTERIA- but fungi.
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pH and temperature are important for the
function of yeast in fermentation and other
processes, as high temps or extreme ph levels
will kill the microorganisms.
OBJECTIVE: 13.03
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Discuss the impact of genetic
engineering on food preservation,
food quality and nutritional value.
Potential Applications of Biotechnology in
Food Science
1. Crops and animals can be genetically
engineered to:
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Survive drought and other harsh local conditions.
Last many times longer in storage than normal
variations.
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Ex- The removal of genes coding for the production
of ethylene in fruit code greatly prolong shelf life by
preventing decay.
Possess increased nutritional value to address
vitamin or energy absences in the diets of a
population.
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Golden Rice and other crops designed to address
nutritional deficiencies often used genes from
microorganisms or animals in plants to produce more
vitamins or other beneficial compounds.
Potential Applications of Biotechnology in
Food Science
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Exhibit insect resistance, negating the
need for the use of pesticides that can
leave toxic residues on crops.
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Successful use of biotechnology insect controls
like Bt have not only reduced insect damage to
crops without the use of pesticides, but also
reduced the occurrence of fungal damage
during long term crop storage.
 (1) Fungal pathogens often occur in the wounds
or around the waste of plant insect pests.
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Remove negative substances found in
plant or animal products:
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Ex: The removal of caffeine from coffee beans.
Potential Applications of Biotechnology in
Food Science
2. Biotechnology can be used to
simplify the production of foods,
decreasing environmental strain and
impacts.
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The enzyme rennin, used to make cheese,
once had to be collected from the
digestive system of cattle.
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Rennin is now produced in unlimited quantities
in genetically engineered bacteria, requiring
little energy, care or processing.
OBJECTIVE: 13.04
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Demonstrate proper food
preservation and sterilization
techniques.
Food Preservation Techniques
1. Freezing- the placement of a food
product in subzero temperatures.
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Increases the shelf life of many foods
indefinitely with varying impacts on food
quality.
Will NOT KILL most common bacteria
(Salmonella, Listeria etc) only make them
dormant.
Most foods should not be refrozen after
thawing.
Food Preservation Techniques
2. Irradiation- the treatment of food
products with low levels of ionizing
radiation to kill microorganisms in
food.
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IS NOT DANGEROUS FOR HUMAN
CONSUMPTION.
Does not alter food quality and taste, and
is in fact, the least invasive method of
sterilization for many food products
including meats.
Food Preservation Techniques
3. Dehydration / Salting- preservation
methods dependent on the removal of water
from food products, providing an
inhospitable environment for
microorganisms.
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Highly effective for meats and many other foods,
but changes taste and texture drastically.
Used throughout history- the only effective
method of storing food through much of ancient
history.
Food Preservation Techniques
4. Pickling- utilizes a vinegar-based
solution to soak foods, creating an
environment in which bacteria may
not survive.
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Effective, but drastically alters taste.
Environment must be acidic enough to be
effective.
Food Preservation Techniques
5. Steam Sterilization- utilizes super
heated water to kill surface bacteria.
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Often used in the processing of meats.
Food Preservation Techniques
6. Oven / Microwave
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Physically cooking foods to proper
internal temperatures ensures the
destruction of harmful bacteria.
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This is the reason most restaurants will not
serve rare hamburger.
Indicators of Food Safety
1. Food containers and process are specifically
designed to ensure food safety.
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The presence of a raised center on the lid of home
canned vegetables or store purchased foods
indicates likely bacterial contamination.
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Botulism is an example of a toxic bacteria often
occurring in such instances.
Abnormal visual growths or smells are often an
indication of the presence of bacterial or fungal
contamination.
Many contaminants are NOT readily recognizable.