Microbiology

1. Food Microbiology
Industrial Canning
Foodborne Diseases

2.  the study of the microorganisms that inhabit,
create, or contaminate food, including the
study of microorganisms causing food
spoilage

3. Goals
- to use microorganism to enhance or
produce new food products (e.g. fermentation,
cheese and wine making)
- to study disease/spoilage-causing
microorganisms and their prevention

4.  Any substance consumed to provide
nutritional support for the body.
 It is usually of plant or animal origin, and
contains essential nutrients, such as fats,
proteins, vitamins, or minerals.

5.  Food Preservation
-The goal is to prolong the shelf life of
food
 Problem
- food spoilage caused by microorganisms

6.  Organic matter.
 Water.
 A neutral pH or a pH that is only slightly
acidic.
 Warmth/heat.

7.  Industrially canned goods undergo steam
under pressure to kill spoilage organisms and
dangerous microbes
 Also known as Commercial Sterilization
 The principle is similar to that of the
Autoclave

8.  Challenge
- to apply the right amount of heat to
destroy microbes without degrading the
appearance and palatability of the food

9.  The goal is to destroy Clostridium botulinum
endospores

10. - a Gram-positive, rod-shaped, anaerobic,
spore-forming, motile bacterium with the ability
to produce the neurotoxin botulinum
-The botulinum toxin can cause a severe
flaccid paralytic disease in humans and animals
and is the most potent toxin known to
humankind, natural or synthetic, with a lethal
dose of less than 1 μg in humans
- produces endospores which are chemical
and heat resistant

11.  Enough heat is applied to ensure sterilization
 Also known as 12-decimal reductions or
botulinal cook
 The goal is to decrease C. botulinum
population by 12 logarithmic cycle
 If there were 10^12 (1,000,000,000,000)
endospores in a can, there would only be 1
survivor after the treatment

12. 1. ThermophilicAnaerobic Spoilage
- Dormant thermophiles may be activated
if canned foods are exposed to very high
temperatures; causes the can to swell due
to gas production
2. Flat Sour Spoilage
- the can is not swollen by gas production
*Both types of spoilage occurs when the cans
are stored in higher than normal
temperatures

13. 3. Underprocessed canned foods
- can be spoiled by mesophilic endospore
forming bacteria
4. Leaks
- leaks may allow entry of microbes into
the can
- microbes may also enter the can during
the cooling process

15.  The ends of the can are bulged or the seal on
the jar is broken
 The product contains gas bubbles or foam, or
liquid squirts out when can or jar is opened;
 Product looks soft, mushy, slimy, or moldy or,
in the case of meat, off–color;
 Product smells spoiled when boiled (heat
brings out the characteristic odor of spoiled
food).

19.  In packaging foods which are stored in
packaging materials that cannot tolerate
conventional heat treatment.
 Packaging materials are fed into machines
that sterilizes the material with hot hydrogen
peroxide and/or ultraviolet light.

20.  Gamma and X-ray radiation can be used to
sterilize food, kill insects and parasitic worms,
and prevent the sprouting of fruits and
vegetables

21. *Gray – measure of ionizing radiation: kGy is 1000 Grays
Organism Dose (kGy)

23.  The International Radura Symbol
- indicates that a food has received
irradiation treatment

24.  Prewrapped foods are submerged into tanks
of pressurized water (can reach up to
87,000psi) to kill bacteria by disrupting their
cellular function
 It also kills nonpathogenic microorganisms
that tend to shorten the shelf life of such
products

26.  Cheese and other dairy products (buttermilk,
sour cream, yoghurt)
 Bread
 Alcoholic Beverages
 Vinegar
 …and other
fermented foods

27.  Also referred to as foodborne
disease or food poisoning
 Any illness resulting from the consumption of
contaminated food, pathogenic bacteria,
viruses, or parasites that contaminate food

28. Can be caused by:
- Bacteria
- Mycotoxins
-Viruses
- Parasites
- NaturalToxins
- “Ptomaine Poisoning”

29. 1. Bacteria
Most common bacterial foodborne
pathogens are:
a.) Campylobacter jejuni
b.) Clostridium perfringens, the "cafeteria germ"
c.) Salmonella spp.
d.) Escherichia coli O157:H7

30. 1. Bacteria
Other ways of causing disease:
a.) Enterotoxins – a protein exotoxin that
targets the intestines
*Emerging Foodborne Diseases – there are new
bacterial infections that are poorly understood

31. 2. Mycotoxins and alimentary mycotoxicoses
a.) Mycotoxins - toxic chemical products
produced by fungi
b.) Alimentary mycotoxicoses - the effect of
poisoning by Mycotoxins
Examples:
- Aflatoxins – from Aspergillus parasiticus and
A. flavus, targets the liver, which will result in
necrosis, cirrhosis, and carcinoma
-Altertoxins – from Alternaria spp.,

32. 3.Viruses
 Enterovirus – FMD, Peri/myocarditis,
poliomyelitis, Diabetes mellitusT1,
Encephalitis
 HepatitisA – jaundice (rarely leads to chronic
liver dysfunction)
 Hepatitis E – liver inflammation
 Norovirus - gastroenteritis
 Rotavirus – severe diarrhea

33. 4. Parasites
a.) Platyhelminthes –Tapeworm, Flatworm
b.) Nematode – Ascaris,Trichinella,Trichuris
c.) Protozoa – Cryptosporidium, Giardia,
Entamoeba

34. 5. NaturalToxins – toxins which are present in
the food itself
Examples:
- Alkaloids from plants
- Grayanotoxin from honey made from
nectar of rhododendron plants
- Phytohaemagglutinin – poison from
uncooked beans (legumes)
- Shellfish toxin

35. 6. “Ptomaine Poisoning”
-An obsolete theory on food poisoning,
before bacteria as causative agent of food
poisoning, suggesting that the poisoning was
due to the “ptomaine” or the alkaloids found in
the decaying animal and vegetable matter

36.  Prevent contaminating food with pathogens
spreading from people, pets, and pests.
 Separate raw and cooked foods to prevent
contaminating the cooked foods.
 Cook foods for the appropriate length of time
and at the appropriate temperature to kill
pathogens.
 Store food at the proper temperature.
 Do use safe water and raw materials.