Food MicrobiologyIndustrial CanningFoodborne Diseases

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

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

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.

Food Preservation - The goal is to prolong the shelf life of

food

Problem - food spoilage caused by microorganisms

Organic matter. Water. A neutral pH or a pH that is only slightly

acidic. Warmth/heat.

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

Challenge- to apply the right amount of heat to

destroy microbes without degrading the appearance and palatability of the food

The goal is to destroy Clostridium botulinumendospores

- 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

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

1. Thermophilic Anaerobic 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

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

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).

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.

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

*Gray – measure of ionizing radiation: kGy is 1000 Grays

Organism Dose (kGy)

The International Radura Symbol- indicates that a food has received

irradiation treatment

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

Cheese and other dairy products (buttermilk, sour cream, yoghurt)

Bread Alcoholic Beverages Vinegar …and other

fermented foods

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

Can be caused by:- Bacteria- Mycotoxins- Viruses- Parasites- Natural Toxins- “Ptomaine Poisoning”

1. BacteriaMost common bacterial foodborne

pathogens are:a.) Campylobacter jejunib.) Clostridium perfringens, the "cafeteria germ"c.) Salmonella spp. d.) Escherichia coli O157:H7

1. BacteriaOther 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

2. Mycotoxins and alimentary mycotoxicosesa.) Mycotoxins - toxic chemical products

produced by fungi b.) Alimentary mycotoxicoses - the effect of

poisoning by MycotoxinsExamples:

- Aflatoxins – from Aspergillus parasiticus and A. flavus, targets the liver, which will result in necrosis, cirrhosis, and carcinoma

-Altertoxins – from Alternaria spp.,

3. Viruses Enterovirus – FMD, Peri/myocarditis,

poliomyelitis, Diabetes mellitus T1, Encephalitis

Hepatitis A – jaundice (rarely leads to chronic liver dysfunction)

Hepatitis E – liver inflammation Norovirus - gastroenteritis Rotavirus – severe diarrhea

4. Parasitesa.) Platyhelminthes – Tapeworm, Flatwormb.) Nematode – Ascaris, Trichinella, Trichurisc.) Protozoa – Cryptosporidium, Giardia, Entamoeba

5. Natural Toxins – toxins which are present in the food itselfExamples:

- Alkaloids from plants- Grayanotoxin from honey made from

nectar of rhododendron plants- Phytohaemagglutinin – poison from

uncooked beans (legumes)- Shellfish toxin

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

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.