Split into two distinct categories, food quality is determined by subjective and objective testing. Whilst subjective testing evaluates product based on sensory tests, such as sight, smell and taste, the latter focuses on the characteristics that can be measured, recorded and analysed with instruments. This is where calibration is important.
The purpose of calibration is to determine if an instrument is still measuring within manufactures specification. Without properly calibrated instruments, the reliability & accuracy of data gathered is highly suspect.
A valid calibration of your transducer is a prerequisite for certification in compliance with ISO9000 requirements. You should decide to calibrate your transducer, particularly if the calibration is no longer valid or an imminent monitoring audit of your measuring tool is due.
Calibration helps to obtain measured values that are demonstrably reliable.
However, like most good things in life “Nothing worth having comes free” and unfortunately, this activity can often become neglected or the interval between calibration checks on instruments can be extended in order to cut costs.
Neglecting calibration can have detrimental effects on a food production process
Greatly dependable on weighing accurate masses within the food industry, calibration can help to avoid potential recalls or legal action due to ‘bad batches’ and reprocessing, all of which could result in damage to the reputation of a business, which is an invaluable asset.
So quality assurance is key, as even if no associations or guidelines were in place, the same commitment to quality would still play a critical role in achieving market success.
However, luckily for the consumer, there are industry regulations in place and almost all regulations and management standards that address food quality and safety stress the importance of calibration: Hazard Analysis and Critical Control (HACCP) regulations that are mandated for meat and poultry, seafood and juice reference:
“Records that document the calibration of process monitoring instruments”
Whilst ISO22000, the food safety management system’s requirements for any organisation in the food chain, states in Section 8.3:
“The organisation shall provide evidence that the specified monitoring and measuring methods and equipment are adequate to ensure the performance of the monitoring and measuring procedures”.
In order to achieve this goal, the following needs to be performed:
- Develop effective procedures for calibration;
- Document those procedures;
- Maintain records of calibration activities, including corrective actions;
- Review records to ensure that procedures are being followed;
Regular Calibration helps to ensure that equipment performs at optimum levels and the data measured is reliable. This, in turn, enhances efficiency, uptime and cost savings, should when you calibrate the instrument you find it to be suspect, the time period of potential suspect data has been kept to a minimal if calibrating on a regular basis.
In addition, with equipment running at optimum performance levels, there is less wastage of raw material, as well as lower pollution which assists in minimising manufacturing expenses, without affecting product quality.
In short, putting off calibration can ultimately cause a variety of quality and compliance issues which can involve heavy costs in more ways than one. So how often should devices be calibrated?
Due to drift, all instruments require calibrating at set intervals. How often they are calibrated depends on a number of factors. Firstly, the manufacturer of the instrument will provide a recommended calibration interval.
HBM – a market leader in the test and measurement market - recommends that calibration is undertaken approximately once a year for electronic devices and at a maximum interval of two years for transducers although; ultimately the end-user is responsible for determining calibration intervals.
This interval may be decreased if the instrument is being used in a critical process or application. Quality standards may also dictate how often a pressure or temperature sensor needs calibrating.
However, the most effective method of determining when an instrument requires calibrating is to use some sort of history trend analysis. The optimal calibration interval for different instruments can only be determined with software-based history trend analysis.
In this way, highly stable sensors are not calibrated as often as those sensors that are more susceptible to drift.
Another misconception is that new instruments do not require calibration. This is not true. Just because a sensor is newly installed does not mean that it will perform within the required specifications.
By calibrating an instrument before installation, a company is able to enter all the necessary instrument data to its calibration database or calibration management software, as well as begin to monitor the stability or drift of the instrument over time.
When it comes to deciding who should be responsible for calibration, food processors are faced with a further decision of whether to choose a OEM or a third party provider?
Previously opting for an OEM could have meant excessive downtime and loss of production as the measuring equipment was removed and sent to a calibration laboratory.
However, with HBM, it is now possible to have most data acquisition equipment calibrated on site, and all transducers calibrated at HBM’s DaKK’s Standard calibration laboratory in Darmstadt.
Once equipment has been properly calibrated a digitally signed electronic copy of the calibration certificate is sent by email directly to the customer. The security of every customer’s data is very important to HBM and for traceability all calibration data is saved on central servers in both company’s UK headquarters in Millbrook and its international headquarters in Darmstadt, Germany.
In addition to calibrating HBM equipment in the field, the HBM’s on-site service is an extension of one of the best-known and most capable DAkkS standards calibration labs worldwide, which is based at HBM in Darmstadt.
Founded in 1977, the HBM Calibration Laboratory is one of the most prestigious facilities in the world.
Regardless of whether calibration and validation activities are performed on-site or in a laboratory, the benefits of making sure that test devices are recalibrated on a frequent schedule are clear.