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FOOD 4310 Study Guide - Hydrogen Peroxide, Cheesemaking, Gram-Positive Bacteria

by

Department
Food Science
Course Code
FOOD 4310
Professor
Keith Warriner

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Discussion 2 Summary Sanitation
Group 3
Chlorine
Description
As an element in cleaning products, chlorine is used to kill bacteria, disinfect and
sanitize food surfaces. It can also be used to clean fruits and vegetables.
For best results, chlorine (or chlorine-based chemicals) should be used at room
temperature (any hotter, and the chlorine compounds may release chlorine gas
which is toxic!). It should also be used at its optimum pH of 6 to 7.
Higher concentrations are highly effective (ie. 50-200ppm) to disinfect food
surfaces. However, very high concentrations of chlorine (ie. higher than 200ppm)
aren't recommended because they can cause corrosion, explosions, and adverse
effects of workers.
The longer the exposure time, the more bactericidal activity there will be.
Note: If the chlorine solution being used is less than 200ppm, rinsing isn't
required. Using chlorine solution that is more than 200 ppm requires a warm rinse
afterwards (letting chlorine stay in contact with equipment for more than
approximately 30 minutes causes corrosion).
Advantages
Kills a broad range of microorganisms
Relatively inexpensive compared to many other chemicals used in sanitation
Can be easily diluted with just water until the right concentration that is desired
Disadvantages
Highly corrosive, posing safety risks for storage, shipping, and handling
Short shelf life
Organic matter (like meat residues) reduces its activity (and also makes
undesirable compounds), therefore, must be used on "cleaned" surfaces only (ie.
remove all visible residues after cutting meat)
Multiple rinses are required to remove residues if surfaces are not cleaned. This
leads to consuming greater amounts of water and a risk of lack of effectiveness
Food Grade Hydrogen Peroxide
Description
H202 is used to sterilize aseptic packaging containers to prolong the shelf life of
products, and also to sterilize food product surfaces.
It can remove unwanted substances such as sulfur dioxide and chlorine residue.
It can be used directly on food to bleach and clean to improve the colour.
H202 is a clear, colourless, and slightly viscous liquid. If left at room temperature
for a period of time it decomposes into water and oxygen.
Hydrogen peroxide with concentrations up to 30%, at up to 80 degrees C, and
contact times up to 15 seconds, has been found to be successful for inline aseptic
packaging. The final product, to meet industry standards, must not contain greater
than 0.5 ppm of H202.

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Originally H202 was approved only on polyethylene, however the approval for
other surfaces soon followed, including polystyrene, ionomeric resins, ethlylene
copolymer resins, and more.
Hydrogen peroxide serves many uses in the food industry besides sterilization of
aseptic packaging.
It is used as an antimicrobial agent in milk for cheesemaking, whey, and starch,
and wine vinegar.
It can be used as an oxidizing/reducing agent in died egg products, wine, corn
syrup, and starch. And also as a bleaching agent in tripe, beef feet, herring, instant
tea, and more.
Advantages
There is no toxic residue. Dosing is controlled in food aplications to minimize
amount of residual H202. Any leftover residue decomposes to water and oxygen in
later steps of processing. Testing for residue is easily accomplished with test
strips or analytical techniques
Easy to handle. Since it is soluble in water, aqueous solutions of the appropriate
strength are easy to prepare. It is compatible with the most common food
processing sanitization techniques, ie. Spraying, dipping and batch mixing.
It is effective. It is a very powerful oxidizer which performs better than most
products, plus with the added benefit of being environmentally friendly
Disadvantages
Can have an adverse effect on product stability. If residual hydrogen peroxide
becomes trapped in the package when it is sealed, it can have an adverse effect on
product stability (particularly ascorbic acid degradation in fruit juices). This is
why it is important to ensure residual levels are low enough before sealing the
product.
Some spores can be resistant. Such as Bacillus stearothermophilus, it has been
proved that dry spores are more resistant than wet spores for hydrogen peroxide.
Has potential to damage tissue. If used improperly, at high concentrations can
damage tissue, resulting in a prolonged healing time.
Quaternary Ammonium Compounds (QUATS)
Description
QUATS are used to clean soiled surfaces in food industry facilities, such as tables
in meat processing plants, or they are used to clean and sanitize floors, walls,
furnishings, and equipment.
QUATs are also effective at cleaning porous surfaces because they are natural
wetting agents.
They are used in some water-based hand rinse sanitizers for personnel because
this chemical is effective against skin flora, such as staphylococci, which can
cause food poisoning and cause sickness.
Its structure is made up of four compounds surrounding a nitrogen which makes
this chemical very versatile because the R groups can be any combination of
saturated, unsaturated, cyclic or non cyclic, substituted or unsubstituted alkyl
groups.
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QUATS are cationic surfactant chemicals and they are active against bacteria,
yeasts, fungi, and viruses. However, they are not very effective against Gram-
negative bacteria.
Advantages
QUATS can have different R groups which allows them to be active against a
wide variety of microorganisms
They are non-toxic, odourless, colourless, non-corrosive, non-irritating
They are good sanitizers because they possess cleaning properties due to its
surfactant activity
Long shelf life
Disadvantages
QUATS are non-compatible with soaps, anionic detergents and anionic matter in
general
They produce foam problems in mechanical operations
They are film forming which can make them difficult to remove from surfaces if
not thoroughly cleaned
Leave residues
Alcohol
Description
The most commonly available alcohols that can be used for sanitizing are methyl,
ethyl, and isopropyl.
In the absence of water, proteins are not denatured as readily by alcohol, and this
explains why a solution of 70 percent alcohol and 30 percent water is a better
sanitizer than 100 percent alcohol. Isopropyl alcohol is the most effective sanitizer
of the commonly available alcohols, with ethyl alcohol being a close second.
Methyl alcohol is not a very effective agent compared to the other two and this
fact, combined with its toxicity, means it is not often used as a sanitizing agent.
Isopropyl alcohol at a concentration of 70 percent is an excellent, inexpensive
choice for sanitizing work surfaces, bottle and flask necks, instruments and your
hands.
Advantages
Fast acting: Alcohol will kill most bacterial organisms in less than five minutes,
but because some organisms may take longer, it is best to let items soak at least
10 minutes to kill the majority present. The low molecular weight alcohols
evaporate readily.
Whereas the lack of esporicidas effects limit sterilization applicants for alcohol,
their general antimicrobial properties can be useful against surface borne bacteria
and other microorganisms.
Pronounced bactericidal as well as some bacteriostatic action against vegetative
forms, the specific effect being concentration and condition dependent.
Alcohols exhibit a wide range of antiviral, antifungal and antimycosal effects.
They are relatively inexpensive, usually easily obtainable and relatively nontoxic
with topical applications.
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