19 Jul The feasability of optimal conditioning techniques in the fresh fruit chain
Society puts an increasing pressure on food industry to deliver a variety of high quality and safe food products from all over the world. Simultaneously, there is a growing awareness about sustainability. Products should be produced in a fair way and losses should be minimized. The fresh fruit chain is an ultimate example where this combination can be a real problem; up to 50% is lost. These losses are dedicated to long lead times, inefficient flows and limited shelf life. Innovative tools should be used to reduce these losses by optimizing the flow of fruits through the chain.
Quality degradation in the food chain
Foods are vulnerable to quality degradation and safety risks, making the logistics of food different from non-food products. All food products have a shelf life. Within this period, it is guaranteed that the products are safe and meet consumers’ requirements. Fresh foods typically have a shelf life of a few days. Examples of products within this category are dairy, meat and fish. Fruits and vegetables are also vulnerable to quality degradation and safety risks, but do not have a fixed shelf life. Their shelf life is just a prediction with a high uncertainty.
Fresh products are an ideal matrix for the growth of a variety of microorganisms. Processing, including cutting and slicing, make products even more attractive to microorganisms. The growth rate of these microorganisms mainly depends on the product storage temperature: higher storage temperatures result in faster growth and therefore faster quality degradation. In general, it can be stated that lower temperatures results in less spoilage and therefore lower losses. However, the difficulty in the fresh fruit chain is that all fruits have a different optimal storage temperature. Some fruits benefit from a low storage temperature, while others suffer from chilling injury: a phenomenon where tropical fruits are stored too cold. Chilling injury might result in a bad appearance and therefore a commercially unattractive product associated with a low freshness.
Not only temperature is important, also the relative humidity and gas composition. Too high moisture contents induce the growth of microorganisms, while a too low moisture content gives the fruit a non-fresh appearance, which is not desired from a commercial point of view. Additionally, an adjusted gas composition can play a role in maintaining product quality. Setting the gas composition to the product optimum can help to extend the product shelf life even more.
Furthermore, time is an important factor in the growth of microorganisms. Extended storage or transportation times significantly increase the spoilage risks as result of microbial growth. Storing products under their optimal conditions would result in the highest quality products and minimizes the occurrence for spoilage. This would mean that all products need an own storage facility were these optimal conditions are implemented. Although this seems a good option to minimize losses, this is not feasible in practice. Practical problems include the limited availability of storage facilities due to the high costs for warehouse space and conditioning equipment. It is therefore more realistic to find combinations of different types of fruits that can be stored under the same conditions.
Sustainability is not the only important aspect in the fruit chain. Consumers from the western world also want to have tasteful products of maximum quality; they are even willing to spend extra money on high quality products. Take for instance the ready-to-eat concept. This means that all fruits are at their maximum ripeness and therefore having their maximum tastiness when being sold.
From a commercial perspective, it is a risk to have ripe fruits in their stores as they might ripen too far. These overripe fruits are vulnerable to infections and might end up as waste. It is therefore the question whether retailers want to maximize their sales by offering perfect ripe fruits or minimize their risk and therefore the amount of waste.
Models can help to get insight in the fresh fruit chain whereby supply chain optimization can help to maximize the retailers turnover, by getting fruits at their perfect ripeness at the right time and place, while simultaneously minimize the chain losses. Take as an example the transportation mode for tropical fruits. Transportation by ship typically takes several weeks, increasing the risk for spoilage. But this way of transport is much cheaper than plane transport. The trade-off between both forms of transport can be done with help of a decision model. It should be noticed that some extra attention should be paid to bundling of different fruits streams when designing a supply chain optimization model. As an example, it is not favourable to transport bananas and strawberries under the same conditions. Strawberries get their maximum shelf life at temperatures just above the freezing point, while bananas suffer from chilling injury at these low temperatures.
Although a lot of attention has already been paid to optimization and efficiency in the fresh fruit chain, there is still a lot to gain. Waste in the fruit chain can not only be reduced by optimizing the flows of goods through the chain, but there should also be focused on valorising waste streams. Take the production of cheese as an example, where high amounts of whey proteins are formed during the production process. In the past, these proteins were just a “by-product”. Now, these proteins have been valorised to important nutrients in a variety of products, making them the most profitable product within the cheese making process.
In the same way, the fruit chain can be brought to a higher level. Models cannot only be used to optimize the flow of fruit through the chain. In addition, innovative tools should be used to determine the “optimal destination” for every piece of fruit. Overripe fruits, low quality fruits with a short remaining shelf life or fruits having a bad appearance can be used for further processing to fruit juice or as food ingredient, while the highest quality products should be used for individual sales. Then, it is not only possible to decrease waste in the fruit chain, but the profit can also be maximized.
Susan is Supply Chain Analyst intern at Argusi. During her study Food Technology at Wageningen University, she has specialized in Supply Chain Management and Operations Research. For her final thesis, she developed a model to optimize the mango chain, while considering the limited shelf life and conditioning techniques. During her internship at Argusi, Susan is using her knowledge to develop a network optimization model for fresh foods. The knowledge on network optimization of Argusi, and Fresh Park Venlo as one of the most important business parks in fresh fruits and vegetables, forms the perfect combination to get more insight in logistic concepts in the fresh fruit chain.