HACCP involves seven principles:

• Analyse hazards. Potential hazards associated with a food and measures to control those hazards are identified. The hazard could be biological, such as a microbe chemical such as a toxins or physical, such as ground glass or metal fragments.

• Identify critical control points. These are points in a food's production - from its raw state through processing and shipping to consumption by the consumer-at which the potential hazard can be controlled or eliminated. Examples are cooking, cooling, packaging and metal detection.

• Establish preventive measures with critical limits for each control point. For a cooked food, for example, this might include setting the minimum cooking temperature and time required to ensure the elimination of any microbes.

• Establish procedures to monitor the critical control points. Such procedures might include how and by whom cooking time and temperature should be monitored.

• Establish corrective actions to be taken when monitoring shows that a critical limit has not been met - - for example reprocessing or disposing of food if the minimum cooking temperature is not met.

• Establish procedures to verify that the system is working properly-for example, testing-time and-temperature recording devices to verify that a cooking unit is working properly.

• Establish effective record keeping to document the HACCP system. This would include records of hazards and their control methods, the monitoring of safety requirements and action taken to correct potential problems. Each of these principles must be backed by sound scientific knowledge: for example, published microbiological studies on time and temperature factors for controlling foodborne pathogens.