Food Science and Biotechnology

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Food Science and Biotechnology

• Biotechnology II

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COMPETENCY 13.00

• Examine techniques and biological processes in
  food science related to biotechnology.

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OBJECTIVE 13.01

• Explore food borne pathogens and spoilage
  organisms in relation to agricultural
  biotechnology.

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Common Food Bourne Pathogens

• 1. Salmonella enteriditus
• 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
• 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.

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Salmonella enteriditus
Source http//www.magma.ca/pavel/science/Salmone
lla.htm
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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.
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Common Food Bourne Pathogens

• 3. Bacterial contaminants usually spread by
  physical contact or ingestion of a contaminated
  liquid or solid.
• 4. Fungi
• A variety of fungi are used in the production of
  foods, including cheeses and yogurt.
• Other fungi are contaminants, some even toxic.
• 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.

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Preventing Food Bourne Pathogens

• 1. Poultry Other Meats
• Meat should be heated in an oven to 74C for at
  least 15 seconds.
• 2. The optimal temperature range for the growth
  of harmful bacteria in foods is between 4C
  60C.
• Low temperatures usually cause dormancy in
  bacteria.
• High temperatures can deactivate or even destroy
  bacteria.

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OBJECTIVE 13.02

• Summarize enzyme activities and fermentation
  processes that are useful in the food processing
  industry.

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Enzyme Activities

• 1. Enzymes are specialized proteins that act as
  catalysts to speed up chemical reactions in
  organisms or compounds.
• 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.
• Important enzymes include amylase, protease, and
  lipase.

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Fermentation Processes

• 1. Fermentation- the anaerobic conversion of
  sugars in plant materials to simple chemical
  compounds.
• Alcoholic fermentation the most common and
  important in biotechnology.
• 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.

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Yeast

• Important microorganisms in the production of
  several types of foods.
• Yeast are NOT BACTERIA- but fungi.
• 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.

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OBJECTIVE 13.03

• Discuss the impact of genetic engineering on food
  preservation, food quality and nutritional value.

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Potential Applications of Biotechnology in Food
Science

• 1. Crops and animals can be genetically
  engineered to
• Survive drought and other harsh local conditions.
• Last many times longer in storage than normal
  variations.
• 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.
• 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.

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Potential Applications of Biotechnology in Food
Science

• Exhibit insect resistance, negating the need for
  the use of pesticides that can leave toxic
  residues on crops.
• 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.
• Remove negative substances found in plant or
  animal products
• Ex The removal of caffeine from coffee beans.

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Potential Applications of Biotechnology in Food
Science

• 2. Biotechnology can be used to simplify the
  production of foods, decreasing environmental
  strain and impacts.
• The enzyme rennin, used to make cheese, once had
  to be collected from the digestive system of
  cattle.
• Rennin is now produced in unlimited quantities in
  genetically engineered bacteria, requiring little
  energy, care or processing.

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OBJECTIVE 13.04

• Demonstrate proper food preservation and
  sterilization techniques.

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Food Preservation Techniques

• 1. Freezing- the placement of a food product in
  subzero temperatures.
• 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.

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Food Preservation Techniques

• 2. Irradiation- the treatment of food products
  with low levels of ionizing radiation to kill
  microorganisms in food.
• 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.

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Food Preservation Techniques

• 3. Dehydration / Salting- preservation methods
  dependent on the removal of water from food
  products, providing an inhospitable environment
  for microorganisms.
• 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.

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Food Preservation Techniques

• 4. Pickling- utilizes a vinegar-based solution to
  soak foods, creating an environment in which
  bacteria may not survive.
• Effective, but drastically alters taste.
• Environment must be acidic enough to be effective.

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Food Preservation Techniques

• 5. Steam Sterilization- utilizes super heated
  water to kill surface bacteria.
• Often used in the processing of meats.

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Food Preservation Techniques

• 6. Oven / Microwave
• Physically cooking foods to proper internal
  temperatures ensures the destruction of harmful
  bacteria.
• This is the reason most restaurants will not
  serve rare hamburger.

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Indicators of Food Safety

• 1. Food containers and process are specifically
  designed to ensure food safety.
• The presence of a raised center on the lid of
  home canned vegetables or store purchased foods
  indicates likely bacterial contamination.
• 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.