Calibration is something that can easily be overlooked during day-to-day equipment maintenance. However, in commercial food processing, a business will rely upon many pieces of equipment to measure and control important aspects of their daily operation. From weight and portion control to temperature and pressure, if equipment is not accurate, then a business will not be able to operate at its best.
Calibration allows businesses to check whether equipment is providing accurate measurements. Regular calibration can help prevent inaccurate measurements from affecting food safety, product quality, production costs and compliance.
What Is Calibration?
Calibration is the process of comparing a piece of measuring equipment against a known reference, or standard, to determine how accurate it is. A calibration check may show that equipment is accurate, slightly inaccurate, or outside its acceptable tolerance.
Not every piece of equipment must be perfect. However, if it is outside the acceptable range, the equipment may need to be adjusted, repaired, or replaced. The required level of accuracy will depend on the equipment and what it is being used for. A device being used to monitor an important food safety control may require more careful monitoring than equipment used for a less critical measurement.
Why Does Calibration Matter?
There are several reasons that equipment should be calibrated. While inaccurate equipment can cause portioning issues and loss of profit, it can also create legal food safety concerns.
Food Safety
Accurate temperature measurements are particularly important when businesses rely on them to monitor food safety, such as refrigeration, cooking, hot holding and probing. If a thermometer is inaccurate, staff may believe food has reached the required temperature when it has not, or believe chilled food is being stored correctly when its actual temperature is higher than expected. This can lead to serious health and safety concerns.
Product Consistency
Scales, temperature controls and other measuring equipment can all affect the consistency of your products. Inaccurate scales can produce inconsistent portions, while inaccurate temperature measurements can affect cooking or processing.
This becomes particularly important when a business produces large quantities of the same product. Small measurement errors repeated across hundreds of products can quickly become significant.
Cost Control
Issues with portioning and stock temperatures will also increase operating costs.
For example, scales that consistently provide inaccurate readings could result in businesses using too much or too little of an ingredient. This can affect portion sizes, recipes and production costs. Similarly, inaccurate vacuum measurements can result in packaging failures and wasted products or packaging materials.
HACCP and Food Safety Management
Calibration can also form part of a business's food safety management procedures. Where equipment is used to monitor a critical control point within a HACCP system, the business needs confidence that the measurement being recorded is accurate.
Calibration records can therefore help demonstrate that measuring equipment is being checked and that the business has procedures in place to identify inaccurate readings.
What Equipment Should Be Calibrated?
Not every piece of equipment requires the same type or frequency of calibration. However, businesses should consider any equipment where an inaccurate measurement could affect food safety, product quality, or production efficiency.
This can include:
- Commercial scales.
- Probe thermometers.
- Fixed temperature sensors.
- Refrigeration temperature monitoring equipment.
- Vacuum packing equipment.
- Pressure gauges.
- Other measuring devices used as part of production or food safety procedures.
Let's go over simple ways to calibrate your equipment.
Scales
Commercial scales can be used for much more than simply weighing ingredients, such as portion sizes, batch quantities, recipe measurements, and the weight of products being prepared for sale.
If a scale consistently reads too high, a business may use more ingredients than necessary. If it reads too low, products could be underweight, or recipes may not contain the intended quantities of ingredients.
Scales can be checked using known reference weights appropriate for the equipment and the required level of accuracy. For example, if a business uses a known 1 kg reference weight, the scale should provide a reading within the acceptable tolerance for that equipment.
The scale should also be positioned correctly and kept clean. Businesses should check that it returns to zero when empty and investigate unusual or inconsistent readings.
Thermometers and Temperature Probes
Thermometers and temperature probes are particularly important in food businesses because temperature measurements can form part of food safety controls. Like other equipment, thermometers can become inaccurate through damage, wear and repeated use. Dropping a probe, exposing it to unsuitable conditions, or simply using it extensively can affect its accuracy.
The easiest way to check the calibration of your temperature probes is through an ice and boiling-point check. An ice-water mixture can provide a reference close to 0°C when prepared correctly. A probe can be placed into the mixture and allowed to stabilise before the reading is assessed.
Boiling water can also be used as a reference point. However, water does not necessarily boil at exactly 100°C in every location, so businesses should not assume that a boiling-water check will always produce exactly the same reading.
Vacuum Packers
Vacuum packers remove air from packaging before sealing the product. The machine needs to achieve the appropriate vacuum and sealing conditions for the intended application. Poorly controlled vacuum levels can result in:
- Excess air remaining inside packaging.
- Inconsistent vacuum levels.
- Poor seals.
- Product leakage.
- Increased packaging waste.
- Inconsistent presentation.
Depending on the machine, checking its performance may involve inspecting vacuum pressure, sensors, sealing temperature, and sealing time.
Warning Signs That Equipment May Need Calibration
Businesses should not wait until equipment completely fails before checking its accuracy. Possible warning signs include:
- Readings suddenly changing.
- Two devices providing noticeably different measurements.
- Scales failing to return to zero.
- Unexpected changes in product weight.
- Inconsistent vacuum levels.
- Products repeatedly falling outside expected specifications.
- Staff reporting unusual readings.
- Equipment being dropped or damaged.
- A sensor or relevant component being replaced.
Equipment should also be checked according to the manufacturer's recommended schedule, even if it appears to be working normally.
What To Do If Equipment Fails Calibration
If a piece of equipment is found to be outside its acceptable tolerance, the business should not simply continue using the inaccurate measurement. The appropriate response will depend on the equipment and what it is used for, but may include:
- Stop relying on the inaccurate equipment.
- Check the measurement using a known accurate device where appropriate.
- Determine when the equipment was last confirmed to be accurate.
- Assess whether any food or products may have been affected.
- Adjust, repair or replace the equipment where possible.
- Recheck or recalibrate the equipment.
- Record the failure and corrective action.
- Review relevant food safety procedures if the equipment was being used to monitor a critical control point.
If inaccurate equipment has potentially affected food safety, the business should follow its food safety procedures and take appropriate corrective action.
Keeping Calibration Records
Calibration records provide evidence that equipment is being checked rather than simply assumed to be accurate. For a record to be useful and accurate, it should include:
- Equipment identification or model number.
- Date of the calibration check.
- Person responsible for the check.
- Reference equipment or standard used.
- Result of the check.
- Acceptable tolerance.
- Any adjustment or repair carried out.
- Corrective action.
- Date of the next scheduled check, where applicable.
For example, a record may look like this, with the addition of specific machinery and staff:
| Equipment | Date | Check | Result | Action |
|---|---|---|---|---|
| Thermometer | 31/08/2026 | Reference temperature check | Within tolerance | None |
| Scale | 31/08/2026 | Reference weight | Outside tolerance | Recalibrated |
| Vacuum Packer | 31/08/2026 | Vacuum verification | Outside specification | Engineer inspection |
Calibration vs Maintenance
Calibration checks whether a measuring device is providing an accurate result. Maintenance involves keeping equipment in good working condition. This could include cleaning, lubrication, and replacing worn components.
For example, a thermometer could provide an accurate reading during calibration while still having other physical problems that require attention. Calibration should therefore be treated as one part of an overall equipment maintenance programme.
Calibration is a relatively small part of equipment management, but inaccurate measurements can have much larger consequences. Whether you are weighing ingredients, checking food temperatures or monitoring a vacuum packing process, your business needs confidence that its equipment is providing reliable results.
Regular calibration checks can help identify inaccurate equipment before it causes food safety problems, inconsistent products or unnecessary costs.
Calibration should also be considered alongside regular cleaning, preventative maintenance and servicing. By keeping accurate records and following manufacturer recommendations, food businesses can maintain better control over their equipment and ensure that important measurements remain reliable.