Week 2: Plant Design & Plant Sanitation

Personnel hygiene facilities and toilets: Enable good personal hygiene to be maintained & prevent any
contamination of food

Welcome to the Plant! Plant Design & Layout

Plant Equipment Design ✅

Cleaning and sanitizing ✅

Plant layout and materials flow, and human movement flow

4 Ways to ensure protection against cross-contamination between and during production.
✅

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

Internal Structure & Fittings: Made of durable materials that is easily maintained, cleaned and
sanitized
✅

Flat internal wall

cleanable

impervious

no toxic effect

Floors

Ceiling: Smooth and covered overhead fixtures to prevent build up of dirt & condensation

Windows

fitted with screen to
prevent entrance of pest

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

4 Factors when considering location ✅

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

External wall, doors, windows and roofs: water and pest proof

Resistant to corrosion and wear

Non-toxic

impervious to spillage of food, water and disinfectants

resistant against cleaning chemicals and slip-resistant

Non-tainting

enable adequate drainage and space to clean equipment (e.g. slope to drain
to prevent puddles)

Durable

easy to clean, maintain & sanitize

8 important Facilities supporting production ✅

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

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

Temperature control:  Ensure adequate facilities for food operations to ensure food safety (Eg Freezer for frozen food storage)

Storage

Air Quality and Ventilation

Lighting

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

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

3 conditions

Ensure adequate lighting to carry out operation in hygienic manner.

5 conditions

Have ventilation systems that can be cleaned & maintained

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)

3 Expectations of Equipment and reusable food-contact containers ✅

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
✅

Materials of construction

Equipment geometry and fabrication

Equipment clean-ability

Non-contact with foods:Less threat to food safety

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]

Mechanically robust, smooth and easy to clean

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 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 ✅

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 ✅

Reduce availability for production

 Longer cleaning times

 More aggressive cleaning

 Less consistent and robust process

 Increased product/equipment testing

Sanitisation Standard Operating Procedures (SSOPs): written procedures that a company
needs to develop and implement to prevent direct
contamination/adulteration of product ✅

Purposes

Identify trends and prevent recurrent problems

Provide a consistent training program for employees

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 ✅

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 ✅

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 ✅

Non-food Contact Surfaces (eg On/off switch, trolleys)

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

Free from accumulation of food spills/dirt/grease in order to
avoid microbial growth and harbourage of pest

Detergents ✅

5 Types

General purpose: mild and effective for lightly soiled surface that
aids rinsing by reducing the surface tension of the soil

Alkaline: denatures and dissolves proteins, saponifies fat,
corrosive towards soft metals such as aluminium and causes precipitates to form hard water

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

interacts with the soil so that the soil does not “clump” together and easier to be removed off the surface

A surfactant basically wraps around soil that repels water so that it can be carried away by the water

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 ✅

Sanitizer used in food industry should have a 5 log aureus within 30sec at 20℃.

2 types

Chemical

Physical

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

Chlorine (eg ClO2 and free chlorine aka hypochlorites )

Limitations

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

precipitate when used in
iron-laden water

Against spore forming bacteria is slightly slower

Corrosive to equipment

Unstable, short residual effect after sanitisation

Quaternary ammonium compounds (Quats): Cationic surfactants that react strongly with cell walls of certain microbes (eg Gram positive bacteria)

Limitations

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

Inactivated by many detergents and hard water

 Expensive

 Foam problem in mechanical application (not suitable for CIP

✅

Detergents and physical
action (scrubbing) remove dirt & organic material covering biofilm

Rinse dirt & organic material to expose biofilm

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

Flat & Smooth

Coved corner flooring to prevent build up of dirt

easy to clean

prevent build up of dirt

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.

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

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