Transcript Food Microbiology

Food Components
Good and Bad
Vitamins
• Can cause a deficiency disease
– Water Soluble
– Vitamin C
– 8 “B Group’ Vitamins
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Vitamin B1 (thiamine)
Vitamin B2 (riboflavin)
Vitamin B3 (niacin or nicotinic acid)
Vitamin B5 (Pantothenic acid)
Vitamin B6 (pyridoxine, pyridoxal, pyridoxamine)
Vitamin B7 (biotin)
Vitamin B9 (folic acid)
Vitamin B12 (various cobalamins;)
Vitamins
• Fat Soluble
• Vitamins A, D, E, and K
• Vitamin Toxicity
– Fat-soluble vitamins are not excreted readily and
because they are stored in body cells,
accumulation may cause toxicity
• Vitamin A and D toxicities are observed more
often then others
Functional Foods
• Functional foods are ordinary foods that have components or
ingredients incorporated into them to give them a specific medical
or physiological benefit, other than a purely nutritional effect.
• Function Foods fall into three categories
– Foods just called Functional foods
• HIGH FIBRE FOODS
– Nutraceuticals
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Dietary phytosterols
Lycopene
Polyphenols
Essential Carbohydrates
– Probiotics
– Optimum health????
Essential Mineral
Potassium
4700 mg
Quantity
A systemic electrolyte and is essential in
coregulating ATP with sodium.
Legumes, potato
skin, tomatoes,bananas, papayas, lentils,
dry beans, whole grains, avocados,
yams, soybeans, spinach, chard, sweet
potato, turmeric.[4][5]
Chlorine
2300 mg
Quantity
Needed for production of hydrochloric acid in
the stomach and in cellular pump functions.
Table salt (sodium chloride) is the main
dietary source.
1500 mg
A systemic electrolyte and is essential in
Quantity
coregulating ATP with potassium.
1300 mg
Dairy products, eggs, canned fish with
Needed for muscle, heart and digestive system
bones (salmon, sardines),green leafy
Quantity health, builds bone, supports synthesis and
vegetables, nuts,seeds, tofu, thyme,
function of blood cells.
oregano, dill, cinnamon.[4]
Sodium
Calcium
Phosphorus
Selenium
700 mg
0.055 m
g
Quanti
ty
Trace
Table salt (sodium chloride, the main
source), sea vegetables,milk,
and spinach.
A component of bones (see apatite), cells, in
energy processing, in DNA and ATP (as
phosphate) and many other functions.
Red meat, dairy foods, fish, poultry,
bread, rice, oats.[6][7] In biological
contexts, usually seen as phosphate.[8]
Essential to activity of antioxidant enzymes
like glutathione peroxidase.
Brazil nuts, cold water wild fish (cod,
halibut, salmon), tuna, lamb, turkey,
calf liver, mustard, mushrooms, barley,
cheese, garlic, tofu, seeds.[15]
Magnesium
420 mg
Quantity
Required for processing ATP and for bones.
Raw nuts, soybeans, cocoa mass, spinach,
chard, sea vegetables, tomatoes, halibut,
beans, ginger, cumin, cloves.[9]
Zinc
11 mg
Trace
Pervasive and required for several enzymes
such as carboxypeptidase, liver alcohol
dehydrogenase, and carbonic anhydrase.
Calf liver, eggs, dry beans, mushrooms,
spinach, asparagus, scallops, red meat,
green peas, yogurt, oats, seeds, miso.[4][10]
Required for many proteins and enzymes,
notably hemoglobin to prevent anemia.
Red meat, fish (tuna, salmon), grains, dry
beans, eggs, spinach, chard, turmeric,
cumin, parsley, lentils, tofu, asparagus,
leafy green vegetables, soybeans, shrimp,
beans, tomatoes, olives, and dried
fruit.[4][11]
Iron
18 mg
Trace
Manganese
2.3 mg
Trace
A cofactor in enzyme functions.
Spelt grain, brown rice, beans, spinach,
pineapple, tempeh, rye, soybeans, thyme,
raspberries, strawberries, garlic, squash,
eggplant, cloves, cinnamon, turmeric.[12]
Copper
0.900
mg
Trace
Required component of many redox
enzymes, including cytochrome c oxidase.
Mushrooms, spinach, greens, seeds, raw
cashews, raw walnuts, tempeh, barley.[13]
Trace
•Required not only for the synthesis of
thyroid
hormones, thyroxine andtriiodothyronine a
nd to prevent goiter, but also, probably as
an antioxidant, for extrathyroidal organs as
mammary and salivary glands and for
gastric mucosa and immune system
(thymus):Iodine in biology
Sea vegetables, iodized salt, eggs. Alternate
but inconsistent sources of iodine:
strawberries, mozzarella cheese, yogurt,
milk, fish, shellfish.[14]
Iodine
0.150
mg
Other Essential nutrients
• Amino acids
• Fatty acids
• Sugars
Essential Carbohydrates
• Eight Essential sugars
– glucose and galactose.
– Mannose, Fructose, Xylose,
– N-Acetylglucosamine,
– N-Acetylglucosamine,
– and N-Acetylneuraminic acid.
• These sugars combine with proteins to create
the glycoprotein chemical messengers
Natural Food Toxins
• Why does everyone fear chemicals and
believe “natural” means safe?
• Is it because synthetic chemicals
cause more cancer?
For synthetic chemicals tested in both mice and rats:
271/451 cause cancer tumors
60%
For natural chemicals tested in both mice and rats:
79/139 cause cancer tumors
57%
Ames, et al., Mutation Research, 2000, 447, 3-13
Case History: Benzopyrene from meat on a barbecue
Natural molecules can become
dangerous during food
preparation!
Historical Events – Plant Toxin?
Opium War of 1839-42
Great Britain has a monopoly on the sale of opium
which it forces on China. Eventually getting control
of Hong Kong.
Consider our societies current “wars on drugs”.
Example – Puffer Fish
 Tetrodotoxin
 100 different species of puffer fish
 Tetrodotoxin used by fish to discourage
consumption by predators
 Low dose of tetrodotoxin produces tingling
sensations and numbness around the
mouth, fingers, and toes
 As little as 1 to 4 mg of the toxin can kill an
adult
Plant Toxins
 Skin
 Gastrointestinal System
 Cardiovascular Systems
 Nervous System
 Liver
 Reproductive Effects
Example – Jimson Weed
 Deadly nightshade plant (Atropa belladonna)
 Used in the Roman Empire and during the Middle
Ages both as cure and a poison
 Women used preparations to dilate their pupils a
sign of allure and beauty
 Atropine is drug responsible for effects
 Counteracts the effects of pesticides and
chemical warfare agents that act by inhibiting
acetylcholinesterase
Example – Mushroom Poisoning
 Most dangerous mushrooms are the “death cap”
(Amanita phalloides) or the “death angel”
(Amanita ocreata).
 Most susceptible are children less than 10 years
of age
 Initial symptoms are nausea, vomiting, diarrhea
and irregular heart rate
 Amatoxin, damages the liver cells causing liver
and kidney failure and possibly death
 Amatoxin is very potent: only 0.1 to 0.3 mg/kg of
body weight results in death
Plant Toxins – Cardiovascular
 Digitalis like glycosides – cardiac arrhythmias
 Foxglove (Digitalis purpurea), squill, lily of the valley
 Contain glycosides that are similar to digitalis
 Heart nerves – decreased heart rate and blood pressure,
general weakness
 Lily, hellebore, death camas, heath family, monkshood,
rhododendron
 Alkaloids, aconitum, grayanotoxin (concentrated in
honey)
 Blood vessel constriction (vasoconstriction)
 Mistletoe (berries contain toxin)
 Toxin is called phoratoxin
Plant Toxins - Nervous System I
 Seizures
 Water hemlock, (parsley family), mint family
 Stimulation – Excitatory Amino Acids – headache,
confusion, hallucinations
 Red alga (red tide), Green alga
 Mushrooms– Amanita family (fly agaric), Flat Pea
(Lathyrus)
 Aberrant behavior – very excitable, muscle weakness, death
 Locoweed - Australian & Western U.S. plant
 Stimulation
 Coffee bean, tea, cola nut
 Caffeine, most widely consumed stimulant in the world
Plant Toxins - Nervous System II
 Neurotoxic – death
 Poison hemlock (Conium maculatum)
 Coniine – neurotoxic alkaloid – Poison used by Socrates
 Paralysis – demyelination of peripheral nerves
 Buckthorn, coyotillo, tullidora (U.S., Mexico)
 Atropine like effects – dry mouth, dilated pupils, confusion,
hallucinations, memory lose
 Solanaceae family – jimsonweed, henbane, deadly
nightshade (Atropa belladonna), angles trumpet
(atropine and scopolamine)
 Neuromuscular – mild stimulation to muscle paralysis,
respiratory failure (curare), deathCoffee bean, tea, cola nut
 Tobacco – South American – Strychnos family (curare)
Blue green alga (anatonin A)
Plant Toxins – Liver
 “Hepatitis” and cirrhosis of liver - From contaminated grain
 Ragwort or groundsel
 Pyrrolizidine alkaloids – attack liver vessels – effects
humans, cattle but some species resistant
 Liver failure and death
 Mushrooms – “Death cap” (Amanita phalloides)
 Amatoxin and phalloidin effects RNA and protein
synthesis
 Liver cancer
 Fungus that grows on peanuts, walnuts, , etc…plant
 Alfaltoxins– produced by fungus in poorly stored grain
Plant Toxins – Reproductive
 Teratogen – malformations in offspring
 Veratrum californicum – native to North America
 Veratrum – blocks cholesterol synthesis –
 Abortifacients
 Legumes (Astrogalus)
 Bitter melon seeds (Momordica)
 Swainsonine toxin – stops cell division
 Lectins - halt protein synthesis– used by humans
Summary
Be aware of what
plants or animals
you eat!
Food Microbiology
Good effects of Microbes in food
• Food Fermentations
– Microbes are deliberately grown in food to produce required
changes.
– Microbes that can not be reproduced synthetically produce
these changes.
– The changes are usually complex and the microbes can often be
grown economically.
• Alcoholic fermentations
Beer, wine, saki etc.
• Dairy fermentations
Cheese, yoghurt, butter,
• Vegetable
Sauerkraut, Tempe, Soy sauce
• Probiotics
• Commensalistic bacteria
Incidental Fermentations
• Some food processes do not use microbes for
the main changes but fermentations may
contribute incidentally to flavours
• Coffee, Cocoa, and Tea
Single Product Production
• Fermentations can be used to produce
ingredients used in food such as
• Citric Acid,
• Vitamin C,
• Vitamin A,
• and Enzymes.
Single Product Production
• Microbes can be grown as food.
• This usually involves converting some cheap waste or
biproduct of another process in to microbial cells that can
be user as human food or fed to stock to convert it to meat
or milk.
• Eg Singe Cell Proteins
– From Waste petroleum material
– Paper production waste (sulphite liqueur)
– Molasses (waste from sugar processing)
• In some areas it is cheaper to grow a high yielding
carbohydrate crop like cassava and the convert it to SCP.
• This produces more grams of protein per acre than growing
a high protein crop like soybeans.
Bad Effects of Microbes on Food
• Food Spoilage
• This is when microbes produce a negative effect on food that make that
food less desirable.
• The changes produced may be called undesirable in one culture but
considered desirable in another. It may or may not make the food
dangerous to eat.
• But is always obviously changed so it is rarely eaten. In this way spoilage as
a beneficial effect by stopping us from eating food that might be
dangerous
– If food is cooked the food spoilage organisms are usually killed. This
allows Food poisoning bacteria to grow with out us knowing. This is because
food poisoning organisms don’t make obvious changes.
• There is many different type of food spoilage but they are usually caused
by saprophytes such as Pseudomoni and fungi.
– Most often plant material is spoiled by fungi
Food Born Disease
• Food Poisoning
• Bacterial food poisoning:
– Staphylococcus aureus
– Clostridium botulinum
– Clostridium perfringens
– Bacillus cerus
Food Born Disease
• Food Poisoning
• Fungal food poisoning
– Aflatoxin Aspergillus flavis
– Ergot
Claverceps purpurea
– Yellow Rice Disease Penicillium
Food Born Disease
• Algae Food Poisoning
– Red Tide Dinoflagellates
– Ciguatera
– Physteria ( Physteria piscicida)
Food Borne Infections
• With infections the organism must grow in the
human to cause an infection.
• This may be confined to the intestine to cause
gastro-enteritis or they may invade the rest of
the body
Food Borne Infections that require a
Large Inoculum
• These diseases are coursed by week
pathogens that require large numbers to
cause a disease and must grow in the food
before it is eaten
– Eg Salmonella,
– Campylobacter,
– E. coli,
– Vibrio Paraheamolytica ,
– Listeria
Food Borne Infections that require a
Small Inoculum
• Bacterial:
– Typhoid Salmonella typhi
– Cholera Vibrio cholerae
– T.B. Mycobacterium tb.
– Q- fever Coxiella burnetii
Food Borne Infections that require a
Small Inoculum
• Viruses
– Hepatitis A
– Polio
– Rotavirus
– Enterovirus
Food Borne Infections that require a
Small Inoculum
• Parasites
• Helminths:
– Tape worms
– Hydatids
– Trichinella
• Protozoa:Entomeba
Giardia
Toxoplasmosis
Cryptosporidium parvum