The present invention relates to a process for harvesting, packing, cooling and subsequently transporting fresh produce, and more particularly, to a process which does not require shipping containers to be coated or impregnated with a wax compound and where the basis weight can be reduced in the paper materials used for fabricating the shipping containers. The present invention provides a cold, wet environment within a fresh produce container, rather than having the container held in a wet, cold environment.
Many methods are in use today for harvesting, packing, cooling and transporting produce. Typically produce is picked from fields when the ambient temperature is above 60.degree. and oftentimes much hotter, such as in the 80s and 90s. Once the product is picked, it must be quickly packaged and often transported over long distances with a significant time period until ultimate marketing. It is a requirement that the produce be cooled and remain in a cooled state throughout the transportation process. Cooling is done to retard degradation of the product, the ultimate consumer, of course wishing to purchase fresh, wholesome produce. Typical cooling processes include hydrocooling, vacuum cooling, icing and forced air refrigeration. A typical state-of-the-art process for harvesting and packing broccoli, and the like would include having a ready supply of wax-impregnated shipping containers (produced from corrugated paperboard) in the field and as the broccoli is harvested, it is immediately placed in a shipping container. Thereafter the containers are iced, meaning the open volume within the packed container is filled with ice. These iced containers are then palletized and refrigerated to maintain the temperature of the fresh produce within a range of from approximately 32.degree.-34.degree. F. What occurs here is that as the relatively warm produce gives up its heat a fair amount of free water is formed by the melting ice. It is for this reason that in the past shipping containers made from corrugated paperboard necessarily had to be made moisture resistant, typically by saturating them with wax. In addition, since the paper materials would be subject to high moisture conditions, the basis weights had to be relatively higher as a design criterion. If the paper portion of the packaging system can be maintained in a moisture-free environment, then lower basis weights can be used without risking strength loss.
Another example is the picking, packaging and shipping of celery which usually is cooled using cold water. Large amounts of cold water are cascaded over the celery stalks after they are placed in wax-impregnated shipping containers.
Not only were these processes undesirable from the standpoint of utilizing large amounts of ice (which simply adds to shipping weight) or cold water, but they also resulted in a wax-impregnated shipping container at the receiving end which had to be disposed of properly after the shipment and use. Today as more and more shipping containers and other paper products are being recycled, it becomes essential to have paper containers that are in fact recyclable without difficulty. The fact that shipping containers contained wax made those containers difficult, if not impossible, to send through a repulping-recycling process. It has thus become highly desirable to utilize nonwax-impregnated shipping container material in the packaging and transport of fresh produce. The fundamental requirement, however, must still be met in that fresh produce as it is picked and packed and subsequently cooled must thereafter be maintained in a fresh and marketable condition. If a shipping container is utilized which does not have objectionable moisture resistant compounds, such as the wax, it cannot then be subjected to large amounts of moisture because the moisture will degradate the strength characteristics of the shipping container. It is of course critical to retain the strength characteristics as a plurality of packed shipping containers are normally stacked in palletized form prior to shipment. During shipment, unloading and distribution, the containers must maintain their structural rigidity. As previously noted, it therefore became a design requirement to use relatively higher basis weight paper materials in fabricating the shipping containers. When using nonwaxed containers, it becomes very desirable to eliminate the use of ice or large amounts of cooling water to cool the fresh produce after packing.
The present invention provides a packaging system whereby objectionable compounds such as wax can be eliminated from the shipping container and where ice or large volumes of water or high moisture are not required for use in cooling. In addition, the present process will utilize a very low moisture (relative humidity) cooling step where the relatively high field temperatures are reduced down to an acceptable temperature range prior to shipping.
Accordingly, from the foregoing, one object of the present invention is to eliminate the use of objectionable compounds within the shipping container so that the container is repulpable-recyclable.
Yet another object of the present invention is to reduce the overall time period for cooling selected fresh picked produce from its field temperature down to its desired transport temperature and to eliminate the use of heavy ice during transport.
Still a further object is to provide a low moisture environment for the shipping container after packing and during shipment without reducing its performing strengths whereby relatively lower paperboard basis weights can be utilized in the shipping container.
Yet another object of this invention is to provide a harvesting, packing, cooling and transport process for fresh produce which is cost effective and results in the arrival of harvest fresh product ready for consumption.
These and many additional objects will be better understood by reading the specification to follow in conjunction with the attached drawings.