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Week 2: Plant Design & Plant Sanitation - Coggle Diagram
Week 2: Plant Design & Plant Sanitation
Welcome to the Plant! Plant Design & Layout
Plant layout and materials flow, and human movement flow
4 Ways to ensure protection against cross-contamination between and during production.
:check:
Prevent raw material/staff handling raw materials flow from crossing the paths of potentially contaminating or finished products i.e.
no criss-crossing and backtracking
Physical segregation (e.g. wall, strip curtain, partition) between "clean" and "unclean" areas.
“Clean” areas" Where contaminants added to the product will be carried over to the final product
"Unclean" areas: where raw material is handled
Allow a
logical flow of process
: For raw materials to progress inwards towards the flow of finished products, storage or despatch i.e. a "straight line" process flow
Proper ventilation
to prevent condensation and eliminate any mould growth. Positive air pressure in finished product area
Internal Structure & Fittings: Made of durable materials that is easily maintained, cleaned and
sanitized
:check:
Flat internal wall
cleanable
impervious
no toxic effect
Resistant to corrosion and wear
Flat & Smooth
Floors
Non-toxic
impervious to spillage of food, water and disinfectants
resistant against cleaning chemicals and slip-resistant
Non-tainting
Coved corner flooring to prevent build up of dirt
Ceiling: Smooth and covered overhead fixtures to prevent build up of dirt & condensation
Windows
fitted with screen to
prevent entrance of pest
easy to clean
prevent build up of dirt
Doors: smooth & non-absorbent material that is easy to
clean/sanitize (eg stainless steel surfaced door)
Food contact surfaces: smooth, non-absorbent material
inert to food & cleaning chemicals
Durable
easy to clean, maintain & sanitize
External wall, doors, windows and roofs: water and pest proof
enable adequate drainage and space to clean equipment (e.g. slope to drain
to prevent puddles)
4 Factors when considering location :check:
Avoid using areas where pollution or industrial activities poses a threat to the safety of food (e.g. near upwind of poultry rearing plant may be a source of Salmonella spp)
Avoid areas prone to pest infestations
Avoid flooding areas
Area where waste can be removed effectively
8 important Facilities supporting production :check:
Drainage and waste disposal: Provide adequate drainage and waste disposal systems and facilities
to minimize risk of contaminating food or the potable water supply
Water Supply
Potable water supply: Follow WHO drinking water quality guidelines.
Non-potable water (e.g. steam production, refrigeration): Have a separate system to be identified and should avoid reflux into potable water
Cleaning: Provide adequate facilities for cleaning food, utensils and equipment and where necessary should have supply both hot and cold potable water
Personnel hygiene facilities and toilets: Enable good personal hygiene to be maintained & prevent any
contamination of food
Adequate hand washing and drying facilities located at entrance to processing area, in all processing areas where staff are required to wash/sanitize their hands. Avoid direct access to processing area.
Toilet with appropriate hygienic design
Sufficient changing facilities for staff
Temperature control: Ensure adequate facilities for food operations to ensure food safety (Eg Freezer for frozen food storage)
Storage
3 conditions
Should be designed and constructed to ensure adequate
maintenance and cleaning, avoid pest access and harbourage
Ensure that food can be protected from contamination during
storage (e.g. appropriate temp. and humidity control)
Provide adequate facilities for the storage of raw materials, food and non-food chemicals (e.g. cleaning materials,lubricants). Cleaning chemicals should be stored separately from foods
Air Quality and Ventilation
5 conditions
Have ventilation systems that can be cleaned & maintained
Provide adequate means of ventilation to minimize airborne contamination.
Control room ambient temperatures and humidity that might affect food safety
Prevent air from flowing from “unclean” areas to “clean” areas
Control odour that might affect the food
Lighting
3 conditions
Ensure adequate lighting to carry out operation in hygienic manner.
Lighting fixtures should be protected to ensure broken glass will not
be a potential hazard
Should avoid misleading of food color due to intensity of lightings.
Plant Equipment Design :check:
3 Expectations of Equipment and reusable food-contact containers :check:
Adequately cleaned, disinfected and maintained to avoid contamination of food
Made of materials with no toxic effect in intended use
Equipment should be durable, movable or capable of being disassembled to allow maintenance, cleaning, disinfection, monitoring and facilitate inspection for pests.
Hygiene Design Principle
:check:
Materials of construction
Non-contact with foods:Less threat to food safety
Mechanically robust, smooth and easy to clean
Direct contact with foods: Commonly stainless steel such as Type 316 with high heat & corrosion resistant, food grade plastic / lubricants.
Resistant of food and cleaning chemicals under the conditions
of use (e.g. low pH, temperature, salt)
Non toxic and inert to food (cannot migrate or absorbed by food)
Easy to clean [ smooth (acceptable roughness parameter ,Ra
value) / non porous / crevices free]
Equipment geometry and fabrication
Avoid stagnant areas or dead spaces where product may
accumulate and be retained for extended time/periods
Avoid sharp corners and metal to metal contact points (not seal-proof, need rubber that is seal-proof)
Equipment should protect product from external
contamination
Equipment clean-ability
Equipment easily dismantled for manual cleaning
Surface easily visible for inspection
(e.g. avoid void areas
where insects might harbour, equipment should be located at
least 1 m away from wall)
Cleaning in place (CIP) technique if used should be satisfactory
even without dismantling
Possible microbial contamination scenarios in plan :check:
Breakdown of an equipment
Significant modification/moving of a processing line
Employment of new staff to clean equipment
Used/ Second-hand equipment is brought in and installed into the
process flow
Consequences of Using Unhygienic Equipment :check:
Reduce availability for production
Longer cleaning times
More aggressive cleaning
Less consistent and robust process
Increased product/equipment testing
Cleaning and sanitizing :check:
Sanitisation Standard Operating Procedures (SSOPs): written procedures that a company
needs to develop and implement to prevent direct
contamination/adulteration of product :check:
Purposes
Identify trends and prevent recurrent problems
Provide a consistent training program for employees
Document that describes chemicals, concentrations,
application methods, time for every part of the plant
Should include some or all the following:
All procedures that will be conducted daily, before (pre-op) and
during production
Specify the employee responsible for the implementation and
maintenance of the procedures (WHO)
Specify the frequency with which each procedures in the SSOPs is
to be conducted (WHEN)
Identify & address, at a minimum, the cleaning of food contact
surfaces of facilities & equipment (WHAT)
Cleaning, sanitizing procedure and method for evaluating
effectiveness of SSOPs (HOW)
Selection of cleaning compounds depends of :check:
Types of soil on surface (e.g. fatty foods, salt)
Type of surface to be cleaned
Amount of soil on the surface
Cleaning method (e.g. soaking, CIP, foam applicator)
Type of Cleaning agent (e.g. liquid or powder)
Quality of water (e.g. water hardness)
Duration of cleaning cycle
Cost of cleaning/sanitising compound
Six steps to clean & sanitise :check:
Dry Clean ~ Physically remove soils
proper brushes to ensure
effectiveness,
AVOID splashing water using the pressure hose on
floors and machinery before all food products are removed
Pre Rinse ~ Rinse until visually free of soils
(preferably with cold
water to avoid coagulation of proteins.
Hot water may be used to remove fat or sugars where protein is not present in significant amounts
Detergent Application~ Wash surface with appropriate detergent (eg CIP)
Detergent Application~ Wash surface with appropriate detergent
Sanitizing ~ Apply after proper cleaning
Flush sanitiser
Used on Food Contact & Non-contact
Surfaces :check:
Non-food Contact Surfaces (eg On/off switch, trolleys)
Free from accumulation of food spills/dirt/grease in order to
avoid microbial growth and harbourage of pest
Food Contact surfaces: surfaces in contact with
human foods. (eg aprons, hands, conveyor belts)
Easily cleanable
made of non-toxic & non-absorbent material that is resistant to the environment/food/cleaning and disinfecting agents
Avoid materials such as wood, ferrous metals, brass and
galvanised metals
Detergents :check:
5 Types
General purpose: mild and effective for lightly soiled surface that
aids rinsing by reducing the surface tension of the soil
A surfactant basically wraps around soil that repels water so that it can be carried away by the water
Alkaline: denatures and dissolves proteins, saponifies fat,
corrosive towards soft metals such as aluminium and causes precipitates to form hard water
interacts with the soil so that the soil does not “clump” together and easier to be removed off the surface
Chlorinated: emove soils through oxidation, aggressive towards
protein based soils, suitable for difficult to clean surfaces
Enzyme: specific to given soil type, used when exposure to
excess alkaline/acid conditions are a problem
Acid: remove inorganic mineral deposits (eg Hard water stones) but not effective against fats, oils and proteins
Effectiveness depends on
Contact time ~ need to penetrate the soil and release it
from surface
Non corrosiveness to the surface
Temperature ~ generally increasing temperature to facilitate penetration and suspension of soil
Water chemistry: Hard water contains
calcium/magnesium salts that react with detergent and
diminish their effectiveness
Physical disruption (scrubbing) ~ assist soil remova
Sanitizers: substances used to control the growth
of microorganisms on clean surfaces :check:
Sanitizer used in food industry should have a 5 log aureus within 30sec at 20℃.
2 types
Chemical
Chlorine (eg ClO2 and free chlorine aka hypochlorites )
Limitations
precipitate when used in
iron-laden water
Against spore forming bacteria is slightly slower
Corrosive to equipment
Unstable, short residual effect after sanitisation
Strengths
Several forms such as powdered
Often bactericidal effect at pH 5 ~ 7, work well at cool water
temperatures without affecting activity
Unaffected by hard water scales
Quaternary ammonium compounds (Quats): Cationic surfactants that react strongly with cell walls of certain microbes (eg Gram positive bacteria)
Limitations
Inactivated by many detergents and hard water
Expensive
Foam problem in mechanical application (not suitable for CIP
Strengths
Non corrosive to metal and non-irritating to skin
Long shelf life (stable in presence of organic matter) and
stable at temp. change, high temp. and wide pH range
Forms a bacteriostatic film i.e. residual antimicrobial activity if
not rinsed
Peroxyacetic acid (acid sanitizers)
Ozone
70% Ethanol
Hydrogen peroxide
Iodophors (Iodine-based sanitizer)
Physical
UV irradiation
Hot water
Steam
Effectiveness
Exposure time ~ more m/o, long exposure time
Temperature ~ increase temp, increase effectiveness
Concentration ~ follow label, not necessary more is better
pH ~ depends on type of sanitizer
Cleanliness ~ soil react with sanitizers and neutralise them
Water hardness ~ Hard water minerals will neutralise quats
Bacterial attachment ~ attachment to surface increase bacteria resistance
Qualities of an ideal sanitiser
destroy vegetative microbes
cheap
soluble in water
concentration easily check
no adverse effects on equipment and consumers
no offensive odour
:check:
Detergents and physical
action (scrubbing) remove dirt & organic material covering biofilm
Rinse dirt & organic material to expose biofilm
Penetrate * inactive biofilm with sanitiser
