Where and why does waste from Fresh-cut leafy salad crops originate?

Salads are partially processed products, for which high quality is a pre requisite. Their production process consists of several step that can be summarized as follow:

  1. Field Procedures: Harvesting of salads on field and in tunnels is a delicate operation, that has to keep the biomass (e.g. leaves) as intact as possible.
  2. Receipt of Raw Materials at the processing plant: Raw materials are inspected for quality and conformity determination. All defective materials are discarded. The first part of leftovers used in our project derive from this phase (defined as L1a).
  3. Preparation Phase- selected Fresh-cut leafy salad crops undergo a first preparation by removing leaves and core. The first part of leftovers used in our project derive from this phase (defined as L1b).
  4. Washing cycles: During production of fresh-cut leafy salad crops there are at lest three washing passages in multiple washing tanks in order to eliminate soil and contamination, without compromising the product quality. The second leftovers occur during washing phases (defined as L2, L3 and L4).
  5. 5 Drying: allows elimination of excess water by passing the Fresh-cut leafy salad crops through centrifuge or drying tunnel.
  6. Optical Sorting /Selector: to meet food safety requirements, Fresh-cut leafy salad crops are processed through a sorting machine, that combining various sorting technologies, permits the elimination of foreign contaminants (metal, plastic, insects etc.). In this phase, salads with different defects are removed generating further leftover (L5)
  7. Filling, packaging, storage, and transportation complete the process

The following scheme summaries these steps

We can thus summarize the quantity of leftovers originated from the production process with an equation:

Lt (total leftover) = L1ab + L2 + L3+ L4+ L5

This total can be added to or subtracted from the initial amount of salad accepted after the quality check and from the sold one. It is possible to say that leftovers are about 40% of the initial product, as shown in the graph. These scraps consist of external leaves and the core removed during the cutting and preparation phase.

Non-Conventional Animal Feed Resources: studying the case of fresh-cut leafy salad crops

This project seeks to study new ingredients for livestock diets in order to respond to the demand of global market, applying the principles of sustainability and circular economy.

What does Fresh-cut leafy salad crops mean? Fresh-cut leafy salad crops market is a fast-growing sector due to the more frenetic lifestyle of developed countries. These types of products offer a service to the consumer that makes them different from fresh vegetables and provide a marketing strategy to relaunch the fruit and vegetable sector, which is also linked to innovative production process technologies. The services offered are cutting, packaging and washing, ending with ready to eat and excellent quality products.

The graph shows the changes in per capita consumption of fourth range salads in selected European countries (Italia fruit news (http://www.italiafruit.net/).

This Percentage distribution of Fresh-cut leafy salad crops: salad (i.e. mixed salads) is the driving force of this sector, also called bagged salads because of their innovative packaging. (Italia fruit news (http://www.italiafruit.net/).

The graph shows the changes in per capita consumption of fourth range salads in selected European countries (Italia fruit news (http://www.italiafruit.net/).

The most commercialized botanical species are:

  • Lettuce (Lactuca sativa)
  • Arugula (Eruca sativa)
  • Endives (Cicorium sativa)
  • Valerian (Valerianella locusta)

 The term salads include two main categories: whole head salad and baby leaf. They respectively are 60% and 40% of the total production.

Baby leaves are a sub-category included in the microgreens one, which are plants at an early stage of growth and harvested earlier than the conventional ones. Additionally, according to some studies, they have a high concentration of vitamins and minerals, and an interesting content of antioxidants as well.

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Can leftover from the production of fresh-cut leafy salad crops become animal feed?

Salad production wastes are leaves potentially rich in nutrients and available in large quantities as well. This means turning wastes into resources. It is advantageous to locally find feed to add in animal diets, which might be used rather than conventional human-meant ingredients. This also leads to a reduction of the environmental impact.

This work however is in progress….

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Salad4Cows