Regulatory information is available on PPECB’s website: www.ppecb.com
Basic Cooling Principles
- Recognise differences between pome fruit cultivars.
- Some apple cultivars (Low Temperature Sensitive – High Risk A) develop internal disorders if stored below 0.0°C for long periods (21 days).
- Some are both Low Temperature and CO₂ Sensitive (High Risk B). The latter should not be packed in unperforated plastic bags.
- CO₂ generation is low at 0.0°C or lower but increases significantly at higher temperatures (1.0 to 5.0°C).
- Early-season fruit with low sugar content is prone to freezing.
- Rapid cooling of some cultivars (e.g. Granny Smith) may lead to core flush.
- Plastic bags are used to retain green colour.
- Certain markets, such as Far East and Africa, demand plastic bags.
- Fruit in plastic bags cools slower than those without plastic bags.
- Fruit in unperforated plastic bags must be loaded out within specified tolerances to avoid possible warming inside containers.
- For fruit packed in plastic bags, the container vents can be closed to save energy.
- When loading pallets with different packaging into a container, those with less effective ventilation (e.g. plastic bags) should be loaded first, as cooling at the door-end of the container is less efficient than near the refrigeration unit.
- It is recommended to close the container vents when fruit is shipped below 0.0°C.
- Fruit treated with 1-MCP may be stored at +1.0°C or higher compared to non-treated fruit.
- Maintain relative humidity between 90 and 95%.
Standard Protocols
Cooling Guidelines for Apples
| Risk Level | Cultivar | Type/Comments | Plastic Bags | Load Out Temp | Set Point | Code | Vents |
|---|---|---|---|---|---|---|---|
| High Risk A | Panorama Golden D (HR) | Early season, week 12 | Yes | 0.0°C to +3.0°C | 0.0°C | D0 | Closed if in sealed bags |
| Golden Delicious (HR) | Early season, week 12 | Yes | 0.0°C to +3.0°C | 0.0°C | D0 | Closed if in sealed bags | |
| Granny Smith (HR) | Louterwater GS, Early Granny S, Brix <11°Brix | Optional | 0.0°C to +3.0°C | 0.0°C | D0 | Closed if in sealed bags | |
| High Risk B | Fuji (HR) | IB prone areas (Internal Browning) | Perforated | 0.0°C to +3.0°C | 0.0°C | D0/D0.5 | Open |
| Joya | As per protocol | ||||||
| Envy | As per protocol, do not cool <0°C | ||||||
| Cripps Red, Cripps Pink, Pink Lady | Late picked | ||||||
| Moderate Risk | Fuji (B) | As per season’s requirements | Optional | -0.5°C to +3.0°C | -0.5°C | D-0.5 | Closed if in sealed bags |
| Gala | Optional | -0.5°C to +3.0°C | -0.5°C | D-0.5 | Closed if in sealed bags | ||
| Starking, Topred Mutants, Braeburn | |||||||
| Panorama Golden D (MR) | Optimum maturity, only first week | No | -0.5°C to +3.0°C | -0.5°C | D-0.5 | Open | |
| Golden Delicious (MR) | Optimum maturity, only first week | No | -0.5°C to +3.0°C | -0.5°C | D-0.5 | Open | |
| Granny Smith (MR) | Optimum maturity, only first week | No | -0.5°C to +3.0°C | -0.5°C | D-0.5 | Open | |
| Low Risk | All treated with 1-MCP | Handle at >0°C to save energy | Optional | -0.5°C to +3.0°C | -0.5°C | D-0.5 | Closed if sealed bags |
Notes:
- Risk Level refers to disorders and damage caused by too low temperatures (freezing, cold damage, internal browning, scald).
- The information above is to be used as guidelines. Specific circumstances, markets, and maturity may require deviations in the interest of quality.
- Early variants of main cultivars such as Panorama Golden Delicious and Louterwater Granny Smith, as well as Golden Delicious/Granny Smith that are not fully matured (e.g. first week of picking), are considered high risk and protocols must be adhered to. Low sugar levels often lead to cold damage.
Cooling Guidelines for Pears
| Risk Level | Cultivar | Type/Comments | Plastic Bags | Load Out Temp | Set Point | Code | Vents |
|---|---|---|---|---|---|---|---|
| High Risk | Early Bon Chretien | Summer Pears, high respiration fruit, cold chain must be maintained at all cost | Most experience is with 37.5 µm bag | -0.5°C to +1.5°C | See rules below | DP1 | Closed if bags are unperforated |
| Bon Chretien, Bon Rouge & Victoria Blush, Rosemarie & Sempre, Flamingo & Sempre, Beurre Hardy, Doyenne du Comice, Cheeky & Cape Rose, Celina & Qutee | Closed if DAT is below 0°C | ||||||
| Packhams Triumph (HR) | DCA Stored (Dynamic Controlled Atmosphere), sometimes act as WBC | Yes | -1.0°C | ||||
| Moderate Risk | Early Season Packhams Triumph | Possible CO₂ damage at 2°C and higher. Low sugar levels are freezing prone | 0.0°C to +2.0°C | 0.0°C | D0 | Closed if in sealed bags | |
| Low Risk | Packham’s Triumph (LR), Abate Fetel, FEMA Forelle & Vermont Beauty, Beurre Bosc, Golden Russet Bosc | Winter Pears | -0.5°C to +2.0°C | -0.5°C | D-0.5 | Closed if in sealed bags | |
| Forelle & Vermont Beauty | Special protocols are to be followed | 0.0°C to +2.0°C | 0.0°C | D0 | Closed if in sealed bags (lower microns, e.g. 20, reduce CO₂ risk) |
Some rules for Early Bon Chretien:
- If full container with bags: can go down to -1.5°C
- If sugar >13° Brix: -1.0°C
- Without bags: -0.5°C
Note: The choice of plastic bag (microns) is important. Lower microns (e.g. 20) are more permeable and reduce the risk of CO₂ damage.