A bulletin for the Australian Food Industry November 2002
Contents: Listeria in ready-to-eat foods | Effect of common sanitisers on Listeria monocytogenes | National Risk Validation Project | Validation of food safety control measures
Validation of food safety control measures
The Codex Alimentarius Commission defines validation within a HACCP system as 'obtaining evidence that the elements of the HACCP plan are effective.'
- Under the heading, Establish critical limits for each Critical Control Point, where it states: Critical limits must be specified and validated if possible for each Critical Control Point.
- Under the heading, Establish verification procedures it states: Where possible, validation activities should include actions to confirm the efficiency of all elements of the HACCP plan.
Validation is thus critical to having an effective HACCP system but has received remarkably little attention from many practitioners and legislative authorities who have concentrated heavily on verification.
The Codex Committee on Food Hygiene (CCFH) has acknowledged the lack of guidance in Codex documents on how one should validate food safety control measures. To address this deficiency the US delegation to the CCFH with the assistance of a number of other countries, the International Dairy Federation and the International Commission for Microbiological Specifications for Foods (ICMSF) has prepared draft guidelines for the validation of food hygiene control measures to be discussed at the Committee's next meeting in January 2003. The authors of the draft guidelines note that in the current environment of outcome based codes of hygienic practice and codes of practice that provide flexibility with the selection of control measures, the concept of validation of food hygiene control measures acquires increased importance.
One could argue that the validation of control measures has always been central to HACCP as it is through this process that one demonstrates that the selected control measures actually are capable, on a consistent basis, of achieving the required level of food hazard control. This is captured in the ICMSF definition of validation as the process of assuring that a defined set of control measures achieves appropriate control over a specific hazard in a specific food.
Food processors have of course had to comply with some mandated procedures for many years, e.g. the pasteurisation of milk must deliver a lethality equivalent to not less than 72° C for 15 seconds. The pasteurisation of liquid whole egg products must deliver a lethality equivalent to not less than 64° C for 2.5 minutes. Many countries, but not Australia, mandate a minimum 12 decimal reduction botulinum cook for low acid canned foods.
However the emergence of new pathogens, increased knowledge of the survival capacity of known pathogens, the development of novel processing technologies and the marketing of minimally processed foods should highlight a greater need for process validation.
- reference to previous validation studies or historical knowledge of the effectiveness of essential control measures. For certain well established processes, it may be sufficient to acquire only the data on a condition or attribute that controls a microbiological hazard.
- scientifically valid experimental trials that document the adequacy of the control measures. Laboratory challenge testing designed to mimic process conditions is such an approach as are pilot tests of the food processing system.
Documentation of the log reduction of pathogens by the appropriate thermal process is an example of this approach to validation.
- collection of biological, chemical and physical contaminant data during normal operating conditions in the food operation. When good veterinary or agricultural practices and good hygienic practices in the field and/or processing establishment constitute the food safety control system, it may be necessary to validate these measures through the use of intermediate and/or finished product sampling and testing based on the use of statistical sampling plans and validated testing methodology.
- statistically designed surveys. This approach can be used to document essential control measures that cannot otherwise be measured and is separate from the type of survey outlined above.
It is reported in Food Chemical News, September 16 2002, that the US Food and Drug Administration sought the views of the National Advisory Committee on Microbiological Criteria of Foods on a number of points raised in the draft proposal prepared by the US Codex delegation.
- the guidelines need to delineate differences between processing plant production procedures which can be validated versus employee behaviour practices, good hygienic practices etc., which are difficult to validate but should be verified;
- the guidelines should also address food control measures that are under a company's direct control versus those such as retail food service, consumer handling, storage etc., that are beyond a company's direct control; and
- the scope needs to clearly address and differentiate between validation activities and verification activities.
For a HACCP food safety plan to mean anything, it must contain only validated critical limits. These must ensure as complete control as possible over hazards in the process. At the same time the critical limits chosen should not be unduly restrictive simply because the necessary scientific investigation has not taken place.
Food Science Australia
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