Cleansing and Disinfection Systems

Introduction: Effective Cleansing and Disinfection

• Four factors to consider for effective cleansing and disinfecting are optimizing chemistry cleansing time for dissolution and emulsification, high temperature over 65°C or low temperature with detergent, chemical activity via concentration, and manual or automated actions.

Introduction: Categories of Cleansing and Disinfection Systems

• There are three categories of cleansing and disinfection systems: Clean-in-place (CIP), Clean-out-of-place (COP), and environmental cleansing.
• CIP refers to the automated cleansing of equipment, without removal, generally for interior surfaces of large equipment and piping.
• COP refers to the removal of food production equipment or portions of the equipment to an external area for cleansing, typically for smaller equipment.
• Environmental cleansing involves cleaning all external surfaces of food processing equipment.

Cleansing/Cleaning

• Cleansing removes dirt and germs from surfaces through physical and/or chemical methods and is the first important step before disinfection.
• Functions of cleansing include preventing physical contamination of food and reducing bacterial growth.
• Soil/Food soil refers to any materials in an incorrect location in food premises.
• Organic soils include sugars, fats, and proteins.
• Inorganic soils include mineral substances.
• Complex soils include combination of food components, dust, cleanser components, and/or hard water salts.
• Water is a basic ingredient of all wet cleansing and is the most common solvent for cleansing agents.
• Hard water contains large amounts of calcium and magnesium salts, which will affect cleansing results.

Methods of Cleansing

• Physical methods of cleansing include physical movement like manual scrubbing, mechanical energy such as scrubbing machines, and turbulence in liquid for equipment like beer lines.
• Chemical methods of cleansing involve the use of detergents by conducting multiple cleansing mechanisms: detergency, solvation, and chemical reactions.

Categories of Cleansing Mechanism: Detergency

• Detergency involves the use of surfactants containing long chain molecules with hydrophilic (water-loving) heads and hydrophobic (oil or fat-loving) tails.
• Detergents exhibits properties of wetting or penetrating the surface crevices to lower the surface tension, emulsifying, and dispersing for cleansing.

Categories of Cleansing Mechanism: Wetting Properties

• Wetting properties penetrate surface crevices to lower surface tension, helping the solution spread and remove soils.

Categories of Cleansing Mechanism: Emulsification Properties

• Emulsification properties remove insoluble, nonpolar substances through emulsification.
• Here, hydrophobic tails surround the soils to aid removal and even a small amount can have a good effect on cleansing

Categories of Cleansing Mechanism: Dispersion Properties

• Dispersion properties involve surfactant molecules aggregating to form micelles to keep soils separated and suspended in the solution.
• A stable suspension of soils is particularly important in preventing redisposition of the soils.

Categories of Cleansing Mechanism: Solvation

• Solvation dissolves the solute in the solvent, with the ability to dissolve soils (solubility); cleansers are used in different pH levels.
• Alkaline cleansers use alkalinity to dissolve organic soils and examples are sodium hydroxide and potassium hydroxide.
• Alkaline cleansers can turn insoluble fat soils into soluble products like glycerol and soap, a process called saponification.
• Acidic cleansers use acidity to dissolve inorganic soils, such as minerals precipitating from hard water in food production.
• Examples of acidic cleansers include citric acid, oxalic acid, sulfuric acid, and hydrochloric acid and they can turn metals into soluble products to create salt of metals.

Categories of Cleansing Mechanism: Chemical Reactions

• Chemical reactions alter the structure of soils at the molecular level to make them easier to remove.
• Enzyme-based cleansers require low temperature cleansing and contain diverse enzyme types, including proteases, amylase, and lipase, to target different soil types.
• Enzyme-based cleansers break down the complex organic compounds into simpler forms and boost the effect of surfactants to remove soils.
• Bio-enzymatic cleansers contain non-pathogenic bacteria to release enzymes, such as proteases, to breakdown protein soils, where smaller pieces of protein soils are digested by bacteria.
• Bio-enzymatic cleansers are more stable and cheaper than enzyme-based cleansers.

Disinfection

• Disinfection is a procedure to eliminate most microorganisms including pathogenic microorganisms on the surfaces.
• Sanitation is a process to reduce the number of microorganisms to a "safe" level.
• Sterilization is an extreme process to destroy all forms of microbial life, including bacterial spores.

Methods of Disinfection

• Non-chemical/Thermal disinfection uses high levels of moist heat to kill microorganisms by disrupting their structure and function using heat-resistant materials, making it easy to apply, non-corrosive, yet with higher energy costs.
• Expose to a temperature of 93°C or greater for at least one minute.
• Expose to a temperature of 71°C or greater for at least three minutes.
• Expose to a temperature of 65°C or greater for at least 10 minutes.
• An operating dishwashing machine is an example; its rinsing water should be able to achieve a temperature of not less than 82°C (FEHD, HK).
• Chemical disinfection uses chemical agents/disinfectants to destroy the cell wall and interfere with metabolism to kill microorganisms rapidly and disinfectants must be diluted correctly.
• Products from approved Bactericidal Agents (FEHD, HK) or "environmental preferable" product should be used.
• Chlorine disinfectant, commonly used in food premises, such as Sodium hypochlorite (NaOCl), denatures the protein in microorganisms, effective in killing the bacteria or virus.
• Chlorine disinfectants contain 5-10% chlorine and need to be diluted before use.
• Use a 1 in 99 dilution of liquid bleach for general purposes such as mopping the floor.
• Use a 1 In 49 dilution for places with serious grime, such as garbage rooms.

Chlorine Disinfectant

• Broadly effective against most microorganisms and is inexpensive but corrosive to metals, irritating to skin, nose, eyes, and throat, and interacts with other chemicals such as with ammonia-based products.

Methods of Disinfection: Ultraviolet (UV) Disinfection

• Ultraviolet (UV) disinfection transfers electromagnetic energy to destroy the genetic material of microorganisms.
• UV-C light is used to deactivate bacteria and viruses such as in UV water purifiers.

Good Practices in Cleaning and Disinfecting

• Develop a cleaning and disinfecting plan to arrange the method used, product used, workflow, personnel, and time required and ensure good ventilation.
• Wear appropriate PPE (personal protective equipment) including protective clothing, face shield, gloves, and/or respirators.
• Using chemical cleaner and disinfectant, label the information of product name, major chemical ingredient, and expiry dates and separate the storage of disinfecting equipment and materials from food or food-processing items.

Personal Hygiene

• The human body is a common source of pathogens.
• High standards of personal hygiene play an important part in creating a good public image and protecting food to reduce foodborne illness.
• Food-handlers must have general knowledge in food safety, food regulation, and a sense of responsibility.

Personal Hygiene Practice

• Maintain a good health condition requiring food-handlers must be free of communicable diseases such as diarrhea, vomiting, coughing, or sore throat, must not be carriers of foodborne illness, and must not have opening wounds.
• If food handlers are suffering or suspected of suffering from communicable disease, they must suspend work and report the illness or symptoms to the supervisor, and seek medical treatment.
• Food handlers need written clearance from health officers before returning to handle food.
• Food handlers with acute gastrointestinal infections need exclusion from work until symptoms have resolved for 48 hours after treatment.
• Open cuts or wounds must be completely protected by impermeable or waterproof bandages or dressings, and gloves.
• Bandages or dressings should preferably not be in flesh color so they can be easily detected on falling off and bandages should be changed regularly.
• Food handles will be excluded from work if the open cuts or wounds cannot be adequately covered.

Personal Hygiene Practice: Proper Work Attire

• Protective wear such as uniform, disposable or washable aprons, working shoes/boots, disposable gloves and mouth masks act as barriers to reduce the risk of contamination.
• Uniforms should be light in color to identify the dirt, washed regularly, and overalls should properly fit.
• Wear comfortable and slip-resistant shoes/boots exclusively in the work area, without high-heeled shoes, sandals, or open footwear for safety.
• Gloves protect food from direct hand contact, especially ready-to-eat food, but it may give a false sense of security as a substitute of hands-washing.
• Hair should preferably be kept short, or long hair tied back, and covered with a clean hat or hair net.
• Remove watches, rings and jewelry before work with food, and jewelry should not be work where it can fall into the food and cause contamination.
• Strong perfume or aftershave should be avoided.

Personal Hygiene Practice: Hand Hygiene

• Keep fingernails short and clean and do not wear nail polish or acrylic nails.
• Keep hands clean at all times before commencing work, before handling any food & after handling raw food, after handling soiled equipment or utensils, after using the toilet, after touching body parts such as ears, hair, nose, and mouth, after coughing, sneezing, eating, and drinking.
• Keep hands clean if engaging in any activities that may contaminate hands, such as handling money or carrying out cleaning duties.
• Hand-washing at least 20 seconds with 10-15 seconds of vigorous scrubbing is recommended by Food Code in 2009, or 40-60 seconds in total as recommended by WHO.
• During hand washing, use warm running water, applying hand-washing product such as a liquid hand soap, rub hands for 20 seconds, rinse hands thoroughly then drying clean paper towels and turn off the tap.

Staff Training

• Provide food safety training to all food handlers when they are first hired.
• Identify training needs by observing their job performance and regularly testing their knowledge, especially the critical control points for food safety.
• Provide retraining in food safety to all food handlers periodically and keep records of all trainings for inspection and legal requirements.
• Keep training entertaining and informative and consider that some staff members learn by doing rather than by just being told what to do.
• Staff members need encourage to actively participate in learning activities and ask questions and be made responsible for their own learning
• On-the-Job Training (OJT) involves learners performing tasks while the trainers tell them how they are doing.
• Good learning options involve training staff members one at a time or in small groups involving demonstrating skills that require employees to perform tasks correctly.

Staff Training: Classroom Training

• Use to train larger groups to introduce or explain the food safety knowledge and basic practices.
• This training should be activity base and could involve Information searches, role-playing, games, guided discussions, demonstrations, jigsaw designs and watching training videos.