Hygiene and control
Control of food safety
How to assure food safety?
best strategies
1. regular cleaning
2. control critical steps during processing
Safeguard product during processing by;
- correct processing
- prevent contamination
- working correctly
end-product testing
- not the best method
- expensive and results often come too late when the product has already reached its expiry
date/has been consumed.
Cleaning: why and how?
Def: the removal or soil, food residue, dirt, grease or other objectionable matter
- does not mention microorganisms?
- but dirt does have an effect on the microorganisms present...
Effects of food residues
- acts as a source of nutrients
- physically protects microorganisms
- chemically reduces the effect of disinfectants because disinfectant then react with the dirt
instead of the microorganisms
- decreases the performance of equipment (eg heat exchangers)
Cleaning vs disinfection
, - Organic soils are most relevant in the food industry
- after determining the nature of the soil, you can determine the best cleaning method
3 aspects of cleaning
- CIP = cleaning in place
Water
- hard water (containing ions Ca2+ and Mg+) can result in scale formation
- acid can be used to clean this but is not advised for everyday cleaning/frequently used
household appliances (kettle)
Alkali/caustic
- used with stainless steel, rubber and synthetic materials
- corrosive: aluminum, tin
- harmful to skin, not done by hand
Detergents
- helps to dissolve water-insoluble compounds
- detergents have polar head and apolar tails and form micelles
- helps to wet the surface
Chemical: sequestering/chelating agents (found in detergents)
- keeps salt in solutions
- prevents deposits
- aids in emulsifying
- may add buffering + wetting
protective colloids
- set viscosity
, Hygienic design
Hygienic equipment = equipment that can be cleaned and freed from relevant microorganisms
- class I: in-place, without dismantling
- class II: after dismantling
Aseptic equipment: hygienically designed equipment that is sterilizable and is impermeable to
microorganisms during production which allows it to maintain its aseptic status.
Hygienic design = cleanability
Disinfection / sanitation
- disinfectant should reduce the number of microbes on a surface with 99.999% (5 log
reduction) in a standard test
- The surface should be CLEANED before disinfection
Methods of disinfection
1. heat (most common method)
- principle: denaturation of proteins
- dry heat / wet heat (steam)
- wet heat is more effective
2. UV radiation
- principle: damage to RNA and DNA
- can only be applied to clear liquids; sterilization of filtered water
3. chemicals
- disinfectants / sanitizers
Different type of chemical disinfectants
Oxidizers
- principle: oxidation, disturb protein synthesis and enzyme systems by removal of Sulphur
groups
cons:
- halogens (Cl, I) sensitive to soil (dirt)
- hydrogen peroxide: degraded by catalase
- peracetic acid: unstable, corrosive
- ozone: very unstable, corrosive
Alcohol
- principle: cause membrane leakage
- NOTE: higher concentrations are bacteriostatic as the organism is dehydrated and can
continue to grow once water is present again
- 60-70% are bactericidal, kills microorganisms (most effective)
Control of food safety
How to assure food safety?
best strategies
1. regular cleaning
2. control critical steps during processing
Safeguard product during processing by;
- correct processing
- prevent contamination
- working correctly
end-product testing
- not the best method
- expensive and results often come too late when the product has already reached its expiry
date/has been consumed.
Cleaning: why and how?
Def: the removal or soil, food residue, dirt, grease or other objectionable matter
- does not mention microorganisms?
- but dirt does have an effect on the microorganisms present...
Effects of food residues
- acts as a source of nutrients
- physically protects microorganisms
- chemically reduces the effect of disinfectants because disinfectant then react with the dirt
instead of the microorganisms
- decreases the performance of equipment (eg heat exchangers)
Cleaning vs disinfection
, - Organic soils are most relevant in the food industry
- after determining the nature of the soil, you can determine the best cleaning method
3 aspects of cleaning
- CIP = cleaning in place
Water
- hard water (containing ions Ca2+ and Mg+) can result in scale formation
- acid can be used to clean this but is not advised for everyday cleaning/frequently used
household appliances (kettle)
Alkali/caustic
- used with stainless steel, rubber and synthetic materials
- corrosive: aluminum, tin
- harmful to skin, not done by hand
Detergents
- helps to dissolve water-insoluble compounds
- detergents have polar head and apolar tails and form micelles
- helps to wet the surface
Chemical: sequestering/chelating agents (found in detergents)
- keeps salt in solutions
- prevents deposits
- aids in emulsifying
- may add buffering + wetting
protective colloids
- set viscosity
, Hygienic design
Hygienic equipment = equipment that can be cleaned and freed from relevant microorganisms
- class I: in-place, without dismantling
- class II: after dismantling
Aseptic equipment: hygienically designed equipment that is sterilizable and is impermeable to
microorganisms during production which allows it to maintain its aseptic status.
Hygienic design = cleanability
Disinfection / sanitation
- disinfectant should reduce the number of microbes on a surface with 99.999% (5 log
reduction) in a standard test
- The surface should be CLEANED before disinfection
Methods of disinfection
1. heat (most common method)
- principle: denaturation of proteins
- dry heat / wet heat (steam)
- wet heat is more effective
2. UV radiation
- principle: damage to RNA and DNA
- can only be applied to clear liquids; sterilization of filtered water
3. chemicals
- disinfectants / sanitizers
Different type of chemical disinfectants
Oxidizers
- principle: oxidation, disturb protein synthesis and enzyme systems by removal of Sulphur
groups
cons:
- halogens (Cl, I) sensitive to soil (dirt)
- hydrogen peroxide: degraded by catalase
- peracetic acid: unstable, corrosive
- ozone: very unstable, corrosive
Alcohol
- principle: cause membrane leakage
- NOTE: higher concentrations are bacteriostatic as the organism is dehydrated and can
continue to grow once water is present again
- 60-70% are bactericidal, kills microorganisms (most effective)
