Along the food supply chains (FSC), energy plays a strategic role, being fundamental to guarantee quality and influential in the determination of economic values. Moreover, the same type of product may flow through chains differing in energy requirement, processing equipment and time spent in the chain itself.
These differences between the FSCs (short vs. longer product lives and storage times, fast vs. slower transportation, low vs. higher energy contribution) motivated the study, which aims at capturing in an analytical model the relationships between the relevant parameters influencing the problem, thus addressing a possible approach to the chain optimisation.
By the modelling approach proposed, jointly looking at economic aspects and energy efforts required to condition and preserve the product quality over time, it is possible to address new considerations for understanding FSCs peculiarities, so as to support decisions and improving the sustainability of the solution adopted.
There are several and different ways for treating and preserving food: however, the greatest part of them requires some contribution of energy. For example, heating was used since the oldest times, because of warm sources availability, while producing cold temperatures, excluding determined geographical areas, has acquired more relevance in the recent times, thanks to energy availability (refrigerators) and, in the years preceding, ice transportability. Nowadays, several supply chains for foods are based on chilled and frozen goods: different transport chains and their technical features are described in James et al. (2006). It is evident that a key element within these chains is energy, also in its different forms, as it is a necessary source to guarantee quality-based processes. Furthermore, the use of energy implies the consumption of resources (frequently, non-renewable ones) and this fact directly influences the sustainability of the FSC considered, together with its economic performance.
Distribution and storage of frozen food fall into the category of “cold chains”, in which the products are kept at low temperature so as to preserve their quality. In “cold chains” energy should be appropriately used to prevent food products deterioration over time, avoiding their value decrease (e.g., due to spoilage of perishable products) and guaranteeing quality preservation.
Food quality and the nutritional value of food itself could be related to some important nutrients characteristics (e.g., vitamin C level for several vegetables, sugar level for several fruits, proteins for meat, etc.), which begin to deteriorate immediately upon harvest or butchery: the aim of cold chains is both to preserve quality and to limit the loss in value over the following stages of the chain from the field to the consumer.
The present paper aims at investigating the role of energy in a FSC where a producer collects the products, freezing them to the temperature set for their preservation, and transports the products to an intermediate distributor for cold stocking before final delivery to retailers. The temperature level must be guaranteed throughout the chain, from the producer to the retailer and frozen products face a cold storage the duration of which determines the level of energy demand. Moreover, the lower the temperature, the higher the energy required and the longer the product life: i.e., the optimisation of the FSC outlined requires the modelling of the chain itself, taking into consideration the temperature set and its impact on quality (i.e., food preservation, together with its nutritional values), energy and associated costs.
The aim is to present a model for FSC configuration encompassing the influence of both temperature and storage time, thus appreciating their impact on product quality, costs and sustainability of the chain, as related to quality degradation and energy consumption.
To this end, the paper will be organised as follows. Section 2 offers a broader view of FSC, so as to set the problem dealt within an appropriate background. Section 3 gives the notation and the framework for the proposed modelling approach. Section 4 is devoted to the comments to the model and to some insights offered by the model itself. Finally some concluding remarks jointly and foreseeable developments are given in Section 5.
The paper proposed introduces the problem of the best alternative of FSC configurations considering, in particular, the influence of the temperature and storage time and their related impact on the product quality, costs and sustainability of the chain as related to quality degradation and energy consumption. The study showed how the energy effort produced in cooling and maintaining products plays a relevant role in the FSC effectiveness and sustainability. The introduction of energy as a key factor of the chain optimisation implies an increased attention for the sustainability of the chain considered, given the strict relationship linking energy and environmental concerns, thus leading to an eco-efficiency perspective of the supply chain.
From this point of view and under the assumptions made, the model proposed allows the understanding of the relationships between quality, temperature and energy, addressing a possible approach to the chain optimisation. Given the growing relevance of the problem dealt with, it is possible to foresee several improvements to the study itself, e.g., considering the effect of transportation, the price decisions at the different stages, the price-elasticity and the freshness-elasticity demand functions at the various levels of the chain. Moreover, “mixed” processing alternatives, which may be found in practise, should be considered, too, such as freezing–defrosting–cooking–freezing or fresh delivery-freezing.
