4. Measurement of produce temperature
Temperature is considered to be measured and stated in Degrees Celsius (°C ) for the purpose of this Code. Any variance from this practice must be highlighted to all parties in the chain to ensure that there is no misunderstanding.
It is most important to bear in mind that chilled fresh produce can be extensively damaged by low temperatures, either by freezing or by chilling injury, if subjected to temperatures below those usually experienced in the growing area.
4.1. Thermometer requirements
4.1.1. All cool store and packing shed operators should possess thermometers suitable for measuring produce temperatures. Note that not all electronic thermometers are suitable.
4.1.2. Electronic thermometers should have a resolution of 0.1°C and be capable of measuring temperatures in the range -5°C to +45°C with an accuracy of ±0.5°C; when measuring a temperature of 0°C, the calibrated accuracy should be ±0.2°C.
4.1.3. Electronic thermometers should be protected from condensation when taken out of cool rooms. If the thermometer case is not sealed, the thermometer may be placed in a plastic bag.
4.1.4. Electronic thermometers should maintain their calibrated accuracy to ±0.3°C when taken in and out of cool stores.
4.2. Thermometer calibration
4.2.1. All thermometers should be checked when purchased. All readings should be noted in a logbook. If the reading suddenly changes, return the thermometer to the supplier for checking.
Rechecking/recalibration of electronic thermometers should be carried out monthly using an ice water slurry, which has a temperature of 0.0°C. A sample method for undertaking this calibration is:
Pack chipped or flaked ice into a wide-mouthed vacuum flask and then fill the voids with iced water. Let it stand for 10 minutes and then insert the thermometer probe into the centre of the flask and record readings every minute until steady. Take at least 4 readings (Ideally distilled water should be used, however tap water is suitable provided it is of drinking quality).
4.3. Produce temperature
4.3.1. The indicating thermometer on a cool store measures air temperature at the location of the sensor. It cannot indicate produce temperature, especially whilst produce is cooling.
4.3.2. To obtain reliable produce temperatures, the sensing probe must be inserted into the flesh of the produce; pre-cool the probe before use by inserting into another sample of the same piece of fruit.
4.3.3. Produce temperature will vary in packages within the one pallet, and from pallet to pallet, depending on the air circulation in the cool store and the stacking density of the pallets. Produce must be chosen from a number of pallets and at varying packing height locations to obtain temperature variability information.
4.3.3. Temperature records of produce should be kept, covering the whole period from the time of harvest to the time of export.
4.3.4. Records should be kept of the cooling rate achieved in each cool room.
Temperature is considered to be measured and stated in Degrees Celsius (°C ) for the purpose of this Code. Any variance from this practice must be highlighted to all parties in the chain to ensure that there is no misunderstanding.
It is most important to bear in mind that chilled fresh produce can be extensively damaged by low temperatures, either by freezing or by chilling injury, if subjected to temperatures below those usually experienced in the growing area.
4.1. Thermometer requirements
4.1.1. All cool store and packing shed operators should possess thermometers suitable for measuring produce temperatures. Note that not all electronic thermometers are suitable.
4.1.2. Electronic thermometers should have a resolution of 0.1°C and be capable of measuring temperatures in the range -5°C to +45°C with an accuracy of ±0.5°C; when measuring a temperature of 0°C, the calibrated accuracy should be ±0.2°C.
4.1.3. Electronic thermometers should be protected from condensation when taken out of cool rooms. If the thermometer case is not sealed, the thermometer may be placed in a plastic bag.
4.1.4. Electronic thermometers should maintain their calibrated accuracy to ±0.3°C when taken in and out of cool stores.
4.2. Thermometer calibration
4.2.1. All thermometers should be checked when purchased. All readings should be noted in a logbook. If the reading suddenly changes, return the thermometer to the supplier for checking.
Rechecking/recalibration of electronic thermometers should be carried out monthly using an ice water slurry, which has a temperature of 0.0°C. A sample method for undertaking this calibration is:
Pack chipped or flaked ice into a wide-mouthed vacuum flask and then fill the voids with iced water. Let it stand for 10 minutes and then insert the thermometer probe into the centre of the flask and record readings every minute until steady. Take at least 4 readings (Ideally distilled water should be used, however tap water is suitable provided it is of drinking quality).
4.3. Produce temperature
4.3.1. The indicating thermometer on a cool store measures air temperature at the location of the sensor. It cannot indicate produce temperature, especially whilst produce is cooling.
4.3.2. To obtain reliable produce temperatures, the sensing probe must be inserted into the flesh of the produce; pre-cool the probe before use by inserting into another sample of the same piece of fruit.
4.3.3. Produce temperature will vary in packages within the one pallet, and from pallet to pallet, depending on the air circulation in the cool store and the stacking density of the pallets. Produce must be chosen from a number of pallets and at varying packing height locations to obtain temperature variability information.
4.3.3. Temperature records of produce should be kept, covering the whole period from the time of harvest to the time of export.
4.3.4. Records should be kept of the cooling rate achieved in each cool room.
