‘Cripps’ Pink’ Best Practice

1.   Correct harvest maturity (for long term storage)

• Starch breakdown: optimum 20-30% and < 40%. Can be released at 15%, depending on other parameters.
• Firmness:> 7.8 kg (11.1 mm tip) as they have to arrive in UK at 8 kg.
• Total soluble solids (TSS): advisable to be above 5% (13% at receival)
• Titratable acidity: 75 – 0.55%

NOTE: Maturity is the biggest factor in diffuse browning development. Post­ optimum harvested fruit should never be stored long-term.

2.   Reduce variability

• Orchards ranked 3 weeks before harvest on maturity and then pre-delivery samples to determine ripening rate and storability.
• Market fruit from orchards with faster ripening rates first and do not store in
• Inside and outside canopy fruit maturity differences need to be
• The outside, well-coloured fruit will be harvested first due to block colour standard of 40% (some markets 60%).
• The inside pale fruit will be left for last in order to potentially colour up. Consider leaf-stripping after first pick when sunburn risk has diminished. Rather consider reflective mulching should sunburn be a risk.
• These inside canopy fruit may be riper (even at the first pick) and should not be stored in CA/ longer than 12 weeks (including shipping time).
• Depending on the size of the first pick, the second pick may be put into CA / long term storage depending on the starch breakdown.
• Avoid extended periods between picks/ long picking
• Do not harvest after 50% starch breakdown for CA storage purposes longer than 12 weeks. May be fine for RA and RA + 1-MCP and short-term CA storage,

3.   Long term storage – orchard history ranking

• Age of trees – do not store fruit from young trees longer than 12 weeks (including the shipping time).
• Light crop load fruit may be more susceptible to disorders/ earlier
• Irrigation status (under or over irrigation may result in faster ripening rates and poor storability).
• Soil types (sandy soil orchard fruit tend to ripen faster).
• Mineral nutrition (important in storage quality/ ripening rate).
• History of progressive defects and ripening rates pre-harvest of each
• Grafted trees may also have a higher internal browning risk due to increased

• Fruit that experienced any type of stress during the season should be packed within one week and sold (maximum of 6 weeks including all handling and shipping).

4.   After harvest and storage handling

• Harvested bins should not remain in the sun and should be accumulated in a shaded area before transport to the packhouse as soon as possible (within the same day of picking).
• At the packhouse fruit should be loaded into the cold room as quickly as possible (within 6 hours from delivery).
• Fruit should not be accumulated outside the packhouse in the shade / overnight to facilitate initial cooling.
• The cold room temperature should not be fluctuating above (3 °C – 4 °C) while adding warm This may lead to excessive temperature fluctuations

/ cooling maintenance or poor removal of field heat.

Separated areas with curtains in the cold room to split warm and cooled fruit may help to avoid this.

Make sure the cooling capacity of cold store can remove the heat from the volume of warm fruit. This should be closely monitored.

Load two or three rooms simultaneously to get even cooling rates.

• Attain pulp temperature of 4 °C after 48
• CO2 should be monitored when warm fruit are closed in a cold
• CO2 levels should never reach levels higher than 1%.
• Use additional lime / new generation scrubbers to reduce CO2 to 5%.
• Fruit should further be cooled stepwise (see below).
• Fruit will benefit from ethylene inhibitors (1-MCP) (to reduce the ripening rate, greasiness, superficial scald and internal browning) and should be treated within 3 days of harvest (maximum 7 days) especially if stored for extended periods in RA (3 months) or CA (> 3 months), but should be used with a stepwise cooling treatment especially for longer storage periods.
• Stepdown cooling treatment protocols (see below) perform better in terms of diffuse and radial browning prevention after long term CA storage (>7 months), in comparison to single storage temperature regimes at 1 °C.

5. CA 02 and C02 gas regimes – Industry Guidelines (ARCJHORTGRO) Nitrogen Flushing: attain gas regime of 3% 02 + <1 % CO2 within 48 hours of sealing the room.

Table 1: Regimes (Appendix 2 Industry Guidelines Apples (ARC/ Hortgro):

6.   DCA guidelines

DCA- RQ / ACR system (Van Amerongen) (PACKHousE EXPERIENCE I vA)

• Room filling (5-7 days); keep CO2 <1%
• Room full (3 days) fruit on temperature; keep CO2 <1%
• Pull down 02 to max 6% (2 days); keep CO2 <1%
• 02 reduction to 2% (7 days); keep CO2 <1%
• 02 1.2% (14 days); CO2 <1% (total 28 days).
• ACR mode > 28 days onwards: 02 > 6%; CO2 <1%
• Keep 02 between 5 – 0.7% depending on the season.
• Always keep CO₂ as close to 5% as possible.
• It is a good idea to monitor the fruit from DCA for ethanol
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DCA-CF system (lsolcel / Gas-at-Site)

Reference: Gas-at-Site, Zanella, 2020/21

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7.     Internal browning considerations

• Fruit maturity (starch breakdown) is linked to diffuse and radial browning development after storage and ripening.

Starch breakdown 15-40%: lower risk of diffuse browning (3 months storage).

Starch breakdown 15-40%: risk of diffuse browning depends on other factors (>3 months storage).

Starch breakdown 40%-50%: higher risk of diffuse browning (>3 months storage).

Starch breakdown 40%-50%: medium risk of diffuse browning (3 months). Starch breakdown >50%: high risk of diffuse browning (3 months).

Starch breakdown 15%-20%: seems to have a higher risk of radial browning after long term storage, especially in combination with a single storage temperature below 1 °C.

• Low storage temperature is linked to diffuse and radial browning development. Storage temperatures of -0.5 °C up to 1 °C have previously been linked to diffuse browning after only 3 months of storage.
• All stepdown cooling treatment protocols reduced diffuse and radial browning after long term CA storage (>7 months), in comparison to single storage temperature regime below 1 °C.
• Soft scald – risk lowered with stepwise cooling

Stepwise cooling treatments tested:

Treatment 1: 1-MCP (SmartFresh5M used in this trial) within 7 days + 30 days at 4 °C, 30 days at 3 °C, 30 days at 2 °C, remaining days at 1 °C (CA: 02

1.5%; CO2 0.5%).

Treatment 2: 1-MCP (SmartFresh5M used in this trial) within 7 days + 30 days at 3 °C, 30 days at 2 °C, remaining days at 1 °C (CA: 02 1.5%; CO2 0.5%).

Treatment 3: 1-MCP (SmartFresh5M used in this trial) within 7 days + storage at commercial CA store (2 °C for 14 days + 1 °C for 14 days + remainder at

0.5 °C until room opened; transferred to US-CA-storage from September and stored at 1.0 °C onwards (CA: 02 1.5%; CO2 0.5%).

• Pre-harvest factors that affect maturity (i.e. younger trees with lighter crops loads and fruit grown on sandy soils) have been linked to diffuse browning.
• Radial browning seems to be linked to pre-harvest temperatures. Be mindful that the risk of radial browning occurrence may be higher in seasons with lower than usual maximum and minimum temperatures as well as GDD10c after 0-50 DAFB (cell division) and 50-100 DAFB (cell enlargement). When long term storage period is determined and fruit allocated for this purpose, the risk of radial browning in each season should be taken into account. These results need to be confirmed. Research is ongoing.
• Irrigation and rootstock trials seem to show differences in maturity /
• ‘Cripps’ Pink’ is CO2 sensitive and readily shows CO2 browning in cases where CO2 increased above 1%.
• Non-perforated bags could lead to the build-up of CO2, especially with fluctuating temperatures during shipping and distribution.
• Never pack high/medium risk fruit in plastic liners in boxes
• Consider shipping container vents 15% open due to CO2 sensitivity and risk of temperature fluctuations during the voyage.