Understanding the Grape for Proper Packaging
Grapes have some traits that require understanding in order to be packaged properly.
KEYWORDS cold chain packaging / food packaging technology / fruits and vegetable packaging
Richard Lindenmuth: Unlike some other fruits, like pears and bananas, that ripen after harvest, grapes do not. They immediately begin to deteriorate — which is exacerbated by varied temperatures from the moment they are picked in the vineyard to the time they reach the grocer’s aisle, and ultimately, the consumer. We know that high temperatures and low humidity cause water loss from the grapes and stems, which ultimately increases the rate of deterioration. Getting the grapes in a cooler temperature and providing them packaging that allows the cooler temperature to be maintained preserves grape quality. This becomes very important to extending shelflife. Maintaining the cold chain with proper cooling and storage, using expanded polystyrene (EPS) grape shipping containers, shelflife can extend up to 120 days vs. less than 10 days with corrugated boxes.
GRAPE PACKAGING, VITIS VINIFERA / VITACEAE
In the United States, grapes are usually sold in wood boxes of 11kg. Apart from these traditional boxes, plastic boxes of 0.5 to 1.5kg, painted in bright colours so as to be attractive to the consumer. The new packages try to be more comfortable and appealing for the consumer; the designs incorporate bags with only one raceme, trays with two racimes, etc.
GRAPE PACKAGING
What an exciting trip to visit a table grape harvest and packing operation at Illume Ag in the Coachella Valley! The grapes shown here are the Midnight Beauties, which are black seedless grapes.
Just to add a little bit of context, the Coachella Valley is the desert located in Southern California. I visited this operation in the middle of June, when the temperatures were well into the hundreds. The benefit of working within the grapevines is the extra shade, but there is no escaping the humidity!
Table grapes (not wine grapes) are grown in two main regions throughout California: the Coachella Valley (southern California) and the San Joaquin Valley (central California). The example provided here is from a growing operation in the Coachella Valley.
When is Grape Season in California?
Between the two main growing regions in the state, table grapes grown in California are available from May to January, with the season starting in the Coachella Valley and ending in the San Joaquin Valley. So, make sure you check your grape packaging to see that you are buying California grown grapes when/where possible!
Table Grape Harvest & Packing
For a detailed overview of the entire harvesting and packing process, check out the video below! In it, you can also see what the bunches look like before harvest compared to the bunches you buy at the grocery store!
The harvesters take carts into the rows of grapevines to harvest. These carts contain multiple bins that will be filled as the workers harvest. (At this particular operation, they use bags to cover the bins and then switch them out once they get dirty.)
They clip the bunches from the grapevines using clippers, and then thin out the bunches based on quality aspects (e.g., not the right color, pruned, has some sort of physical defect such as cracking). One really notable difference regarding the table grape harvesting process is the slowness and attention to detail. The workers are carefully selecting the grapes that are ready for harvest, and then removing the fruit that does not meet quality specifications.
Once all of the buckets have been filled, they take them to a designated packer.
Harvesting Table Grapes
Table Grape Packing
Once the carts have been filled, the containers go to a designated packer in the field. Each packer has a set packing table, where they pack the table grapes into bags and then into boxes/containers. In this case, you can see that they are packing the bags into both cardboard boxes and Styrofoam containers. This is based on the customer, and in this case, the Styrofoam containers were for international customers.
Table Grape Packaging
One thing that is consistent regardless of the actual box type, is the set up of the box. There is a bag, a liner and then after all of the bags of grapes have been included, a Sulfur Dioxide pad is included, the bag is closed and so is the outer container. The Sulfur Dioxide pad acts as a fungicide, which is very commonly used with conventionally grown table grapes, and the use is included on the label for each bag of grapes, as well as the label for the outer packaging. (Click here if you would like to learn more about why and how Sulfur Dioxide is used.)
Table Grape Packing Process
During the packing process, the packers are doing a second quality check. They have a set of clippers and will remove any fruit that does not meet quality specifications that the harvester might have missed.
The packers then determine which/how many clusters go into each bag.
Eight bags fill up a box, are weighed to make sure they fulfill the weight requirement for the customer and then are palletized.
Once the pallets are complete, they are covered and then will be taken to the cooler to await transportation to the customer.
Packing Table Grapes
Packing Table Grapes
Questions about Table Grapes
How are table grapes harvested?
They are harvested using clippers, and the workers remove any excess/undesirable fruit.
Are any tools used to harvest table grapes?
Yes, small clippers are used.
Do all of the grapes get harvested at the same time or are there multiple passes through the vineyards?
All table grapes are harvested at the same time. Any fruit that may not be ready for harvest or are already passed their harvest time are left on the vines.
How do they know when table grapes are ready to be harvested?
This is specific based on the grape cultivar being grown, but in general, it is based on the Soluble Solids Concentration (SSC) and color of the fruit. The actual time of harvest is determined based on taking a sample of the fruit in each block and using the results to determine if the fruit is ready for harvest. These are referred to as maturity indices, and you can learn more of the specifics related to table grapes on the UC Davis Postharvest website.
Are table grapes packed in the field?
Yes, they are commonly packed in the field (as you saw in the example above). There are also other examples of them being packed in packing houses, but it is a similar process and no wash water is used.
Are any tools used during the table grape packing process?
Yes. Packing tables and clippers are used. The packing tables are used to pack the grapes, and the clippers are used to remove any fruit that might have been missed during the harvesting process.
Why are Sulfur Dioxide pads used with table grapes?
To help prevent pathogen growth and to keep the green stems greener for longer. The green stems are an important marketing aspect, as consumers associate them with freshness.
Are Sulfur Dioxide pads used with organic table grapes?
No, they are not allowed to be used with organic grapes. (Click here to read more about the use of Sulfur Dioxide and the associated rules.)
Does the grape bag/packaging reflect the use of the Sulfur Dioxide pads?
Yes, all grape bags (and any other form of direct packaging) is required to include that Sulfur Dioxide has been used. In the example above, the use of Sulfur Dioxide is included on each individual grape bag, as well as on the boxes.
New long life packaging of grapes without the use of sulphites
Nov 15, 2016
At this final stage of the season, the Fra.Va. Company has decided to adopt the microwave technology of FIT - Food & Innovative Technologies from Polignano a Mare (a province of Bari), for the packaging and preservation of grapes.
Fra.Va. Company, leader in Puglia for the production and commercialization of cherries and table grapes, became in 2014 the first to adopt a FIT system from 2 pallets, deciding to focus on preservation without sulphites (SO2) - cf. FreshPlaza of 20.01.2015.
The use of sulphites can actually alter the taste of the grapes, and often does not guarantee good preservation. Furthermore, the residue from high doses can cause a reaction to sensitive consumers who are intolerant to this allergen.
With the new ULMA packaging machinery installed in 2015, in addition to the flow pack baskets (500 and 1000 g.), the company is now able to pack both 30x40 and 30x50 formats with ease.
GRAPE PACKAGING SYSTEMS
"This packaging and the entire FIT process, already approved by our customers, - explains Vito Valenzano, General Manager of Fra.Va. - enables us to naturally maintain the grapes over time and without any alteration to taste and appearance, and is proving to be very functional for the product's management during transport, handling in distribution, as well as on the shelves."
"This system, in fact, guarantees the preservation of the product throughout the supply chain, even after long breaks in the cold chain (over 24 hours), thus helping to dramatically reduce waste in retail, in consumers’ homes, as well as in our stores."
"The transparency of the material used - says Vito Valenzano - also facilitates the visual inspection of the product on arrival after a long journey, or after the period of retention/storage in cold storage. It is much easier to check the product's status before sending it to the distribution or for sale."
The future of Fra.Va. Company is certainly oriented towards presenting itself to customers and markets (EU and non-EU), as well as appreciating the intrinsic quality of the fruit Made in Italy, particularly its closeness to nature and the taste of its grapes.
Thanks to the innovations introduced by Fra.Va., the consumer can discover the typical taste of freshly picked fruit, and at the same time enjoy a genuine product that will safeguard their health and well-being.
The paper reports the formulation of an active GRAPE PACKAGING based on PET coated with a Layered Double Hydroxide (LDH) hosting 2-acetoxybenzoic anion (salicylate) as antimicrobial molecule. The release of the molecule anchored to the LDH, compared to the molecule free dispersed into the coating, appeared much slower. Permeability of carbon dioxide and oxygen through the packaging at different temperatures was evaluated, as well as the capability of the active material to inhibit Pseudomonas, Listeria and Lactobacillus. Table grape was stored in thermal stress conditions (i.e. 10 °C) into the active packaging and the total mesophilic aerobic count and yeasts and moulds population was evaluated up to 14 days of storage. The experimental results were used for a theoretical prediction of shelf life of the packed grapes and compared with the same fruit packed into untreated material. Global and specific migration of salicylic acid from the active packaging demonstrated, in compliance with the migration limits of the EU regulation, the suitability of the considered material for food contact.
In recent years, the food packaging materials based on polymers are in continuous evolution, in response to the increasingly complex needs of the markets, of the distribution times and conditions and of consumers’ safety. Therefore, packaging systems are becoming increasingly sophisticated thanks to the rapid evolution of science and technology in producing new materials. The fast development of nanotechnologies is accelerating the innovation in food packaging field and several applications of nanomaterials in packaging and food safety have been studied and developed. They include, for instance, composites based on polymer and active nano-fillers as high barrier packaging materials, reservoirs of antimicrobial agents, nanosensors for the detection of food contaminants or monitoring the packaging conditions integrity (Bugatti, Vertuccio, Zuppardi, Vittoria, & Gorrasi, 2019; Duncan, 2011; Gan & Chow, 2018; Pucciariello et al., 2004; Sorrentino, Gorrasi, & Vittoria, 2007; Souza & Fernando, 2016). Active packaging systems are developed with the goal of extending shelf life for foods and increasing the period of time in which the food is of high quality.
The controlled release of antimicrobials from packaging materials represents an important innovation in active packaging. Antimicrobials incorporated in packaging materials could extend shelf life by preventing bacterial growth and spoilage. This system could potentially increase the stability and specificity of preservation and reduce the amount of chemicals needed in foods. It has been demonstrated that the use of nanostructures can achieve levels of functionalities in some cases very difficult to reach using bulk materials.
The use of hybrid inorganic-organic materials is increasing considerably, in fact manipulating on nanometer scale the matter it is possible to design advanced materials with specific structure and functionalities. Among the inorganic fillers that can modify the polymers’ properties and functionalities, Layered Double Hydroxides (LDH) are very attractive and versatile (Costantino, Marmottini, Nocchetti, & Vivani, 1998; Costantino, Nocchetti, Gorrasi, & Tammaro, 2011). They are composed of positively charged brucite-like layers of divalent and trivalent metal hydroxides in which the excess of positive charge is compensated by anions and water molecules between the interstitial position. They can be represented by the general formula: