Module 10 Flashcards
Foodborne Illness
Any illness that is related to the consumption of food or contaminants or
toxins in food
Pathogens
Microorganisms that can cause disease
Toxins
Substances that can cause harm at some level of exposure
Cross-contamination
The transfer of one contaminant from one food, piece of equipment or
person to another
Threshold effect
Many microorganisms do not cause harm but after reaching their
threshold, however, they can cause foodborne illness
Salmonella
- Most common cause of bacterial food-borne illness in the US
- Found in feces.
- Poultry and eggs are the main contaminated foods.
- Also found in dairy, seafood, fresh fruits, and vegetables
- Killed by heat.
Campylobacter jejuni
- Leading cause of bacterial diarrhea in US
- Sources: Undercooked chicken. unpasteurized milk, untreated water.
Shigella spp
- Contamination usually through fecal-oral route
- Common in salads and raw vegetables.
E coli
- Normal inhabitant in GI of all animals
- Undercooked ground beef frequently implicated
Listeria monocytogenes
• Fatality rate of 21% • Fresh soft cheeses, ready-to-eat deli meats, hot dogs • In pregnant women can cause fetal loss – Avoid unpasteurized milk and cheeses during pregnancy – Cook (until steaming hot) leftover foods or ready-to-eat foods, such as hot dogs – Wash hands to avoid cross- contamination if preparing these foods for others
Vibrio spp:
• Grow in warm seawater (especially during summer months) • Organism has been isolated from oysters, clams, and crabs • Consumption of these products raw or undercooked may result in illness
Bacterial Foodborne Intoxication:
• When illness is caused by toxin produced by
bacteria, not by the organism itself
• Unlike food infections, intoxication can be caused by
only a few microorganisms
• Once formed, toxin cannot be destroyed by cooking
• Most common
– Staphylococcus (staph)
– Clostridium (botulism)
Staphylococcus aureus (staph):
• Bacteria live in human nasal passages
– Can be transferred to food through the
coughing or sneezing of food handlers
• Foods frequently contaminated:
– Ham, salads, bakery products and dairy
products
Clostridium botulinum (botulism):
• Bacteria produces a neurotoxin – deadliest bacterial food-borne toxin • Toxin causes paralysis (I.e., Botox) • Botulinal toxin has been found in: – Improperly canned foods, low-acid foods such as potatoes and stews held in large containers – Botulism spores can contaminate honey so it should never be fed to young children under the age of 1
Preventing Oxidation/Rancidity
• Double bonds in fats are susceptible to oxidation
– Rancid butter
– Deep fat fryers
• Oxidation of fruits and vegetables can also turn
them brown
– Apples
– Salad bars
Antioxidant food additives
– Vitamin C, Vitamin E
– Sulfites
• In processed foods - alcoholic beverages (wine) and drugs
• “Fruit Fresh” (used to be added to all salad bars)
BHA and BHT
• Prevents rancidity in baked goods and snack foods
• Large amounts fed to animals have been shown to reduce
cancer
– Amount in human diet unlikely to be of benefit
Purposes of Direct Additives
• To maintain product consistency – Example: Emulsifiers •give products a consistent texture •prevent them from separating • To improve or maintain nutrient value – Vitamins & minerals are added to many foods to make up for •those likely to be lacking in a person's diet •lost in processing
Purposes of Direct Additives
• To maintain palatability & wholesomeness
– Preservatives retard product spoilage caused by
mold, air, bacteria, fungi or yeast
• To provide leavening or control acidity/alkalinity
• To enhance flavor or impart desired color
– Many spices and natural and synthetic flavors
enhance the taste of foods
Biotechnology
• Biotechnology is a collection of scientific techniques, including genetic engineering • Used to create, improve, or modify plants, animals, and organisms • Manipulate DNA for the purpose of changing the characteristics of an organism or creating a new product • The sequence of bases in genes codes for the sequence of amino acids that are joined to form proteins. • The proteins determine the traits of organisms.
Passing traits from parent to offspring
• When two organisms breed, some genes from each are
passed to the offspring.
• New combinations of genes and the traits for which they
code appear in the offspring.
• Over millions of years, genes have been changed by
mutations.
• Biotechnology speeds up the process of introducing new
traits that can be passed through generations.
Traditional breeding vs. Biotechnology
• Almost every fruit, vegetables, or crop grown today has been genetically
modified using traditional selective breeding techniques
– Some of these crops would not have developed without human
intervention
– Allowed us to produce food that is
• more nutritious
• can better withstand harsh environments and resist disease
Hybridization
– Process in which two related plants are cross fertilized – Resulting offspring has characteristics from both parent plants – These methods introduced the genes for traits that add to the quality and productivity of various plants
Crossbreeding
– Used in livestock
– Two types: Inbreeding and Outbreeding.
Inbreeding
–crosses between closely related animals to
intensify desirable traits
–but may also intensify undesirable traits
Outbreeding
–crosses unrelated animals to reduce
undesirable traits
–increase variability and introduce new traits
Techniques of Traditional Breeding
• These techniques work well but they have limitations
– time consuming
– a new trait can only be produced once in the
reproductive cycle of plant or animal
– only same or closely-related species can be interbred
– both desirable and undesirable traits can be
transferred
Biotechnology (Cont.)
• Is a more sophisticated, more powerful approach to genetic
modification
– has enormous potential for increasing
• Yield
• Quality of the food supply
– has created safety concerns
• Relies on the techniques of recombinant DNA
– also referred to as genetic modification or genetic
engineering
– to alter the DNA of plants or animals to
• produce new traits
• enhance desirable ones
Biotech Method #1:
– Gene is pasted into a loop of bacterial DNA called a
plasmid
– The plasmid, containing the gene of interest, is taken up
by a bacterial cell
– Bacterial cell can then transfer the gene to a plant cell
– Once inside the plant cell, the new DNA migrates to the
nucleus
– The gene for the new trait is integrated into the plant’s
DNA
•The DNA is then referred to as recombinant DNA
– because the DNA from the plasmid has been combined
with the plant’s DNA
Biotech Method #2
– Involves painting the desired segment of DNA
onto microscopic metal particles
– These are then loaded into a “gene gun” and
shot into the plant cells
– Once inside the cells, the DNA is washed off
the metal particles by cellular fluids
– DNA migrates to the nucleus
– Is incorporated into the plant’s DNA, forming
recombinant DNA
Herbicide resistance:
allows farmers to achieve weed-free fields that –require fewer pesticides –increase crop yields –lowers price for consumers
Insect resistance:
By introducing a gene from bacterium Bacillus thuringiensis that produces a protein that is toxic to certain insects but is safe to humans and other animals – the plant produces its own insecticide – environmentally friendly – reduces the cost of farming
Disease resistance
fruits and vegetables have
been modified to resist viral
infections
FDA (Food and Drug Administration) GMOs
Regulates safety and labeling of GM foods
USDA (U.S. Department of Agriculture) GMOs
Regulates agricultural products and research concerning
development of new plant varieties
EPA (Environmental Protection Agency) GMOs
Regulates GM foods that are able to protect themselves
from insects or disease
