Packhouse practices for blueberries
The processing of blueberries at the packhouse facility must be well regulated and controlled. In any case, blueberries must be subjected to (forced air) cooling as soon as possible. Rapid removal of field heat is essential for blueberries, so a location with a cooling facility should be near the production fields. The activities in the packhouse contribute in large extend to the final product quality. It is therefore of utmost importance to have a careful handling in the packhouse and at the same time an effective berry sorting to deliver a high quality product
Fast cooling down of blueberries
Upon arrival at the packhouse blueberries should be cooled down as quickly as possible to remove the field warm. To increase the effect of reducing product temperature on quality, cooling should be carried out preferably within 1 hour after harvest and not longer than 4 hours upon picking. Moreover, blueberries should be cooled down with forced-air cooling to reach the desired temperature faster and allow for a more uniform cooling through the pallet load. Subsequent grading, packaging, labelling and palletization should be performed under 10°C to keep the product temperature as low as possible.
Activities at the packhouse
Sorting blueberries in the packhouse. Photo by Raota/Shutterstock.com
Grading and sortingAlthough grading and sorting may damage the berries, it contributes to a more uniform product quality and to keep the number of defective berries at a minimum level. In the case of manual harvesting defective berries can already be removed during picking. Currently, grading and sorting machines equipped with vision systems are available to automatically detect and remove quality issues as a severe shriveling, bruising, cuts, compression damages and attached stems/flower. Special attention is required to minimize berry damage during this grading and sorting process.
Packed blueberries. Photo by hsfoto/Shutterstock.com
PackagingThe packaging is not only important to avoid mechanical damage but also to reduce dehydration and subsequent loss of firmness and crispness. A wide range of consumer packages (primary packaging) is applied, based on different packaging materials and designs. Also different sizes ranging from small volumes of 125g to 500g berries are used depending on the market and product price. The use of a Modified Atmosphere package (MAP) depends on the final market destination. Elevated CO2 concentrations, within certain limits, may contribute to suppress fungal decay and delay softening. The consumer packages are placed in carton boxes or crates in pallets ready for further handling.
Labelled boxes. Photo by WUR
Labelling and palletizationFilled packages must be stacked on a pallet and labelled with information including packhouse code, size/class and batch number. Further the name of the fruit and net weight must be mentioned on each label. The exact requirements can differ depending on local regulations and client demands. The completed pallets must be well strapped so that the packaging cannot shift or fall. Often cardboard edge protectors are used to stabilize pallets. As soon as pallets are completed, they need to be moved to the cold storage and kept refrigerated at 0-4°C.
Cleaning the packhouse is important. Photo by Sorn340 Studio Images/Shutterstock.com
Cleaning and maintenanceProper cleaning and sanitizing of building and equipment is part of good packhouse practices. Besides maintenance as prescribed by the supplier, a good cleaning and sanitizing of equipment such as the grading line is necessary prior to use. Sorting belts must be clean and have smooth surfaces. All surfaces that could lead to bruising or puncturing of fruit should be well covered for example with impact absorbing foam