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The optimal usage of cleaning agents, sanitisers and disinfectants to minimise the risk of traces in foods

Legislation in relation to cleaning, sanitising and disinfection activities in food production:

The use of chemicals is not usually intended to expose food or feed to active substances contained in them. This clearly differentiates between the prevailing applications of sanitisers and disinfectants on one hand, and plant protection products / veterinary medicinal products on the other. However, it is acknowledged that the use of cleaning agents, sanitisers and disinfectants during the production, preparation, processing, treatment, packing and transport of animals, plants, food or feed may lead to the presence of traces in food or feed, and those traces may in many cases be unavoidable.

There is no aligned global regulation in relation to cleaning, sanitising and disinfection activities, and food companies must therefore seek information themselves about local / national legislation when developing and implementing onsite cleaning, sanitising and disinfection processes.

Management of cleaning and disinfection:

For food business operators, cleaning procedures and frequencies are part of Good Manufacturing Practices (GMP) and food safety management systems, including HACCP. The design of cleaning, sanitising or disinfection programmes is normally based on the outcome of the food business operator’s hazard analysis and risk assessment of production and cleaning processes, and relevant regulatory requirements. How to make a detailed, formalised and documented hazard analysis and risk assessment of cleaning processes and chemicals is outside the scope of this User Guidance.

In line with GMP and food safety management systems (e.g., HACCP), food business operators must have a comprehensive, fully evaluated, validated and documented hygiene schedule for all equipment and food facilities. These systems should be prepared in collaboration with company technical and production personnel, cleaning chemical representatives, quality (laboratory / quality assurance) and other suitably qualified personnel.

Designing a hygiene schedule:

Food business operators designing their first hygiene schedules are recommended to consult experts for assistance, e.g., chemical suppliers, trade associations, equipment suppliers and regulatory officials.

The following sections present issues to consider when designing a hygiene schedule. 

Information about active substance(s) in cleaning agents, sanitisers and disinfectants:

Material Safety Data Sheets (MSDS) must be supplied covering information on substances being used, e.g. stability and reactivity properties, toxicological information, personal protective equipment (PPE), disposal / waste handling, transport information and regulatory status.

Cleaning agent / sanitisers / disinfectants specification:

Relevant points to consider:

• Registration under relevant legislation;
• Applications e.g., sink sanitiser;
• Suitability for various equipment surfaces, e.g., staining and corrosion information;
• Chemical interactions;
• Effective pH and temperature ranges;
• Claims, e.g., efficacy against microorganisms, efficacy of biofilm removal, etc.
• Directions for use, e.g., surface visually clean, dilution;
• Concentration of active;
• Recommended contact time;
• Storage, e.g., to minimise chlorate build-up;
• Shelf life and stability;
• Suitability with respect to various surface materials;
• Organoleptic effects on product, e.g., taste;
• Component traceability;
• Third party endorsements / verifications, e.g., field trial data.

Storage instructions:

Storage of cleaning agents, sanitisers and disinfectants can significantly affect their end use or efficacy.

Some regulatory bodies require defined physical and chemical parameters to be monitored and recorded prior to use.

All cleaning chemicals must be kept in their original containers and must never be mixed with other chemicals, even if they are the same chemicals, in order to avoid unintended contamination.

Instructions to minimise by-product build-up:

In general, cleaning agents, sanitisers and disinfectants can react with other chemicals in the water, leading to unwanted by[1]products. The table below of known by[1]products from commonly known cleaning chemicals must be stored at appropriate or recommended temperatures in well ventilated areas away from heating, ventilation, and air conditioning intake vents; this helps preventing any fumes from spreading to other areas of the facility.

Storage must be under supplier’s specified conditions and in compliance with local regulatory requirements.

First In First Out (FIFO) principles must be followed for use of product batches.

Physical separation of chemicals

Cleaning agents, sanitisers and disinfectants are not intended to come in direct contact with food products. Issues to take into consideration are:

• Physical separation of chemicals from food products and process equipment as part of GMP to avoid contamination;
• Following suppliers’ guidelines regarding best storage / separation practices for chemicals to avoid unintended reactions between chemicals, e.g. oxidising agents, chlorinated chemicals and acids.

General usage instructions for cleaning agents, sanitisers and disinfectants:

The recommendation is to follow the chemical supplier’s usage instructions for the product. Local regulatory requirements must also and always be complied with.

Cleaning, sanitising or disinfection should be aligned to prerequisite programs / HACCP based risk assessments. Cleaning, sanitising or disinfection processes must be managed so they do not compromise the safety of product, e.g., in a multi-line production area, or in relation to product changeover.

A dirty surface cannot be sanitised or disinfected effectively as the biocidal active substance(s) is hindered from coming into contact with microorganisms trapped in and under soil. Extraneous organic material also dilutes and neutralises biocides before they are applied to surfaces. Neither large quantities of sanitisers and disinfectants nor high-pressure application can replace effective and thorough pre-disinfection cleaning.

Effective cleaning must therefore be carried out before applying a sanitiser or disinfectant to allow an effective reduction in the number of microorganisms.

There should be a pre-determined sequence of cleaning, sanitising or disinfection. The following sections give guidance and basic considerations for developing cleaning, sanitising or disinfection procedures.

Cleaning process:

The cleaning process usually consists of the following steps:

• Remove gross debris from surfaces;
• Apply detergent to loosen soil and microorganisms and hold them in solution or suspension;
• Rinse with water to remove loosened soil and traces of detergent;
• Dry clean or apply other appropriate methods for removing debris;
• Where necessary, sanitise or disinfect.

The choice of detergent depends on the type of soil, age of soil, water hardness, the temperature of the method, the types of surfaces and safety. In general:

• Alkaline detergents are used for the removal of organic soils, while
• Acidic detergents are used on inorganic soils.

Detergent suppliers usually have a range of options for various specific circumstances.

Rinsing is carried out if appropriate to the cleaning method (e.g., CIP, COP, Wet Manual etc.). Rinsing removes soil and detergent traces from equipment surfaces.

Once cleaning has been completed, sanitising or disinfection can be carried out using chemicals appropriate to the type of surface material. For example, caustic products are corrosive to soft metals (e.g., aluminium). The supplier’s recommendations may be checked regarding the suitability of chemicals for the type of materials used in the production facilities to clean.

Sanitising or disinfection processes:

The sanitising or disinfection process usually consists of the following steps:

• Dilute as per supplier’s instructions. If sanitiser or disinfectant is stored after it has been diluted it may not be fully effective owing to its chemical instability. Follow all instructions on product label.
• Apply the sanitiser or disinfectant to food contact surfaces and surfaces where there could be contamination with food (e.g., food splash area, equipment handle), in accordance with instructions, starting at the highest point and working downwards;
• Leave the sanitiser or disinfectant on surfaces for as long as indicated in the supplier’s instructions and in compliance with local regulations.

The choice of most appropriate sanitiser or disinfectant depends on the effectiveness and safety precautions, such as: targeted microorganisms, water quality, equipment surface materials, application temperature / time, environmental considerations, associated food label claims and workers’ safety.

Cleaning agent, sanitiser and disinfection suppliers usually have a range of options for various and specific circumstances. Advice should always be sought from them.

Hand hygiene:

Microorganisms are removed from hands by effective washing and drying.

Sanitising / disinfecting may be required by authorities as an additional precaution, leading to reduced risk of transmission of microorganisms from the operator’s hands to foods and food contact surfaces, which could potentially cause critical food safety issues.

Washing hands is an absolute must:

• When working with different types of food, for example with raw meat then with vegetables;
• After using the toilet;
• After blowing one’s nose;
• After coughing and / or sneezing in one’s hand;
• Before and after treating a wound;
• After handling waste;
• After performing cleaning activities;
• When re-entering the production area, for example after a break;
• Before putting gloves on.

Sanitising / disinfecting hands: When and how?

Sanitising / disinfecting hands is regarded as being effective when done after each hand wash.

Always consult the chemical supplier to select the correct chemicals to establish appropriate hand hygiene measures.

Minimizing traces of cleaning agents, sanitisers and disinfectants on food contact surfaces:

Potential traces of cleaning agents, sanitisers and disinfectants in food are dependent on the levels of cleaning agents, sanitisers or disinfectants on the surface, the effectiveness of removal techniques after treatment and the surface area to volume ratio of the food in contact with the surface.

The areas with the greatest potential to transfer traces of cleaning agents, sanitisers or disinfectants include those with a high ratio of surface area to volume of food, surfaces with crevices and cracks and difficult to reach areas. For example, meat slicers or mincers will be more likely lead to higher traces of cleaning agents, sanitisers or disinfectants in food.

Basic considerations are:

• Assess and justify the need for validation and verification of cleaning, sanitising or disinfection processes;
• Assess and justify the need for monitoring food for traces of cleaning agents, sanitisers and disinfectants;
• If needed, implement a monitoring programme with easy and simple measurable acceptance limits (e.g., pH measurements) and define corrective actions and preventive controls.

Control measure principles:

Below are some measures to minimise the potential presence of traces cleaning agents, sanitisers and disinfectants on those surfaces requiring extra attention:

• Inspect treated equipment / utensil surfaces to determine whether the amount of any traces of chemicals used in cleaning, sanitising and disinfection are at the appropriate level. When cleaning includes a rinsing step, this is a very important control measure which needs to be properly validated and verified (see sections 10 and 11);
• Use lower concentrations coupled with longer contact time if sanitiser or disinfectant can be left overnight on production equipment. Consult the chemical supplier, MSDS and instructions if considering this option;
• Only apply detergent, sanitiser and disinfectant as per the product instructions and consult with the chemical supplier if necessary to ensure product suitability for the planned application;
• For larger sites with limited food product ranges, undertake the risk assessment of discarding the first few items off the production line after cleaning;
• Rinse or wipe sanitiser or disinfectant after use. This can substantially reduce traces on the surface. However, rinsing will introduce water into the production area, and increased risk of Listeria monocytogenes, thus potentially compromising hygiene and food safety. Consult the chemical supplier, MSDS and instructions if considering this option;
• Sanitise or disinfect smaller items in a dishwasher if practical to do so. Such sanitising or disinfection processes need to be validated, verified and monitored;
• Follow a validated cleaning, sanitising / disinfecting process that ensures compliance with any regulatory residue limits.

Chemicals used in cleaning, sanitising or disinfection for which no legal residue limit currently exists should be used appropriately, with a view to assuring food hygiene and safety whilst minimising risks.

It is important to note that the most suitable control measure for one food business might not be the same as that for another. For example, some food production facilities are intentionally dry, for which rinsing would be inappropriate. Similarly, the use of water in high risk / care food production facilities should be restricted to minimise the risk for Listeria monocytogenes and ensure food hygiene and safety.

Verification and monitoring:

Verification is the activity that confirms that the food safety management system, e.g., HACCP plan is being followed. If the HACCP plan is designed correctly, adherence to it will result in safe food.

Monitoring methods may include:

• Visual inspection;
• Microbiological swabs;
• In process / finished product testing;
• Microbiological checks of rinse water;
• Hygiene / housekeeping audits.

Verification activities vary with the type of product and processes; they may include:

Ensuring that the prerequisites are under control, e.g., the cleaning procedure with specified chemicals and conditions is adhered to;

Ensuring that the personnel carrying out the verification activities have the appropriate qualifications, training and experience, i.e., they are competent to undertake the verification activity;

Checking the efficiency of cleaning (including final rinse steps) and sanitation or disinfection, including verifying and formally recording at routine intervals (see Appendices for examples of hygiene recording templates).

The frequency of verification should be based on a risk assessment, e.g., every time for critical processes (e.g., a wet process with rinsing steps) and high-risk food (infant formula), and less frequently for dry processes.

Corrective action must be carried out as and when required to improve cleaning, sanitising or disinfection results.

Possible causes of sanitising or disinfection failure include:

• Not following product instructions;
• Over-diluting sanitiser or disinfectant during pre-mixing or application;
• Incomplete or inadequate cleaning;
• Poor sanitiser or disinfectant penetration or coverage;
• Insufficient contact time on surfaces;
• Inadequate temperature and humidity while the sanitiser or disinfectant is being applied;
• Inactivation or neutralization of the sanitiser or disinfectant by traces of cleaning agents which were not adequately rinsed before the disinfectant was applied;
• Untrained personnel

Methodology for assessing the efficiency of cleaning, sanitising or disinfection processes and presence of traces in food products:

For some food, e.g., infant formula, vegetarian dishes, non-pork meat products or products with allergen free claims, it might be necessary to make a formal and documented validation of cleaning, sanitising or disinfection processes. The validation must demonstrate that the cleaning, sanitising or disinfection processes consistently remove or reduce potential contamination to an acceptable level from:

• Residual products, microorganisms, allergens and soil;
• Traces of chemicals from cleaning, sanitising or disinfection.

Waste water handling:

The food business operator must ensure safe and efficient removal of waste water from the cleaning and disinfection processes.

Basic considerations are:

• Local regulatory requirements;
• Potentially required permission to drain waste water from cleaning and disinfection processes into the public sewerage systems;
• Waste water compliance with local regulatory requirements and approvals at any time;
• Advice from chemical suppliers on proper disposal methods for cleaning and sanitising chemicals and disinfectants.

Chemical disposal:

Waste from cleaning agents, sanitisers and disinfectants must be disposed of safely.

Basic considerations are:

• Supplier guidelines;
• Any regulatory requirements for the disposal of chemical containers and / or expired products.

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