validation verification & monitoring

Validation verification & monitoring

Validation, verification and monitoring are critical components of food safety and quality management programs.


"Obtaining evidence that the control measures managed by the HACCP plan and by the operational PRPs are capable of being effective"

In other words, and in relation to cleaning, is the cleaning programme capable of meeting its objectives, e.g. the removal of allergens.

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Cleaning validation

Cleaning validation is not directly a legal requirement but is seen as food manufacturing best practices. Indeed, audit schemes based on the Global Food Safety initiative (GFSI) such as the British Retail Consortium (BRC) Global Standard for Food Safety Issue 8, provide guidance on the need for validation. Clause 4.11.3 states that: ‘Where cleaning procedures are part of a defined pre-requisite plan to control the risk of a specific hazard, the cleaning and disinfection procedures and frequency shall be validated and records maintained’. In other words, BRC are advocating that validation is required when the cleaning and disinfection programme is intended to control a hazard.

The need for validation is summarised below:

  1. Where the cleaning and disinfection programme is designed to control a hazard, it must always be validated.

  2. Where the cleaning and disinfection programme is designed to control a brand protection issue, validation is at the discretion of the food manufacturer

  3. Where the cleaning and disinfection programme is designed to control a quality or process control objective, validation is not advocated.

A clean is deemed effective when the desired levels of cleanliness, chemical, physical and microbiological have been achieved. Testing whether this is the case can be done through a number of techniques; the choice of test depending on the hazard that is being controlled (microbiological, physical, chemical).


Microbial validation

It is possible to measure the bacterial contamination on a surface by traditional swabbing and evaluation techniques.

  1. Total Viable Count gives a measure of the total bacterial contamination on a surface.

  2. Coliform Count gives a measure of the type of bacteria that have come from the gut of an animal.

  3. Enterobacteriaceae Count, now a more favourable evaluation technique than Coliform counts, is also indicative of gut-borne microorganisms but also environmental microorganisms. An increase in Enterobacteriaceae count may be indicative of poor hygiene practices or conditions within the processing environment that can lead to microbial growth (particularly of pathogens).

  4. Pathogen testing gives a measure of the presence or absence of a specific pathogen such as Listeria monocytogenes.


Allergen validation

A quantitative process, validation testing for allergens normally employs Enzyme-Linked Immunosorbent Assay (ELISA) technology or DNA identification, although the latter is only semi-quantitative.

The limits of detection for ELISA methods will vary between allergenic proteins, however they are typically in the μg region (parts per million) between 0.5 and 20 ppm.

The major downside for the food processing industry of ELISA systems is the cost (typically £75 per sample) and the time factor which is measured in days and for this reason this technology can only be used to validate (or verify) that an allergen has been removed.


"Confirmation, through the provision of objective evidence, that specified requirements have been fulfilled.”

Verification is undertaken using methods that may take several days to provide results and thus asks the question, did the cleaning programme work effectively on the day of verification sampling?

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Hygiene verification

Verification is a series of analytical data, records and observations that provide evidence that cleaning programmes have been historically, successful (or not).  Traditionally, records have consisted of cleaning programme sign-off sheets by hygiene staff to indicate that cleaning programmes have been undertaken and by production staff to record that the food processing environment was fit for production.

Traditional microbiological testing via surface swabs and sponges for open surface cleaning or via final rinse water samples for CIP have indicated the surface microbial population at the time of swabbing.  The types of tests available have already been noted in the section on Microbial Validation and require 24-48 hours to complete for simple tests or more than 7 days for e.g. the identification of specific pathogens.  Whilst some advances have been made to speed up microbiological testing, it is still not quick enough to be used as a monitoring technique.

Cleaning programmes can be routinely audited to demonstrate that they are being carried out with respect to best practice and written procedures either internally (1st party) as part of an ISO9001 system, via Holchem as the chemical supplier (2nd party) or via fully independent auditors e.g. BRC (3rd party).


"Conducting a planned sequence of observations or measurements to assess whether control measures are operating as intended”

Monitoring is undertaken in real time and asks the question, is the cleaning programme working now?

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Monitoring consists of a series of observations or tests to determine either whether the cleaning programme is currently fit for purpose (times, temperatures, chemical concentrations) or food processing (and environmental) surfaces are clean.


Hygiene monitoring

Prior to any analytical testing of the cleanliness of surfaces, surfaces should first be visually assessed.  This can be via direct observation, smell or the rubbing of the surface with a clean white cloth or gloves to try and determine any physical indications of soiling.  Surfaces that are physically dirty, require no other testing to determine the success of the physical cleaning performance.

Measurement of any residues of food present on surfaces can then be carried out, typically with commercial ATP or Protein test kits, and can give quick results during the cleaning process to establish whether a re-clean is required.

For example, ATP testing uses the presence of Adenosine Triphosphate on reaction to create pulses of light that can be read using an instrument. Also, protein or glucose testing and rapid allergen testing can identify any residues on a surface determining whether a re-clean needs to take place.


Allergen Monitoring

Specific tests exist called Lateral Flow Devices which can deliver a presence/absence result in a matter of minutes, ensuring that a surface can be made available for processing in the knowledge that the allergen of concern is not present.

The technology is similar to ELISA in that an antibody – antigen reaction is taking place with a visual indication revealing the presence or absence of the allergenic protein.

Using this technology either a food sample or environmental contact swab can be taken to test for the presence of, for instance: Peanut, Hazelnut, Almond, Casein (Milk), Egg, Gluten, Shellfish & Soya.

It is also possible to use DNA testing to look for allergens and animal species.


Chemical Monitoring

Any cleaning regime requires the selection of the correct detergent and disinfectant strength, with routine checks carried out to ensure that this desired strength has been met.


In-line monitoring

Most acid or caustic, cleaning in place (CIP), detergents can be monitored in-line by conductivity. The conductivity probe and controller must be calibrated, and temperature compensated, to ensure accuracy; as a rule, each 1°C rise in temperature will increase conductivity by approximately 2%.

With peracetic acid and chlorinated based products redox measurement is generally used because conductivity tends to be unreliable and inaccurate.


Chemical titration

The strength of detergents or disinfectants should be checked regularly through chemical titration. This can be done either in a QC Laboratory using traditional burettes or by a dropper bottle method, with the chemistry identical in both.

A common misconception is that a burette is more accurate than a dropper, but this is largely untrue with a dropper often delivering a more precise measurement.


Test strips

Colour change test strips provide a quick indication on the approximate concentration of certain active components in a detergent or disinfectant, whilst pH paper will deliver a quick indication of any residual acidity or alkalinity following on from a detergent clean.

Test strips looking for PAA and QAC can give a good indication as to the strength of the disinfectant.

Test Kits & Inspection Equipment

A comprehensive range of test kits and inspection equipment.

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