How to maintain the cold chain in food and pharmacy? Isothermal packaging: requirements and tests

2023-02-24

The purchase of products through the internet is increasing due to the change in consumption habits and the evolution of new technologies. Reports on shopping habits through the e-commerce channel indicate that the food and pharmacy sector are increasingly in demand.

42% of online spending on mass consumption is destined to food products, according to data from Aecoc Shopperview. Moreover, the market share of FMCG e-commerce in 2023 will exceed the current 3%. Even the pharmaceutical sector has been moving into digital commerce with exponential growth in recent years and is expected to continue growing, reaching a turnover of almost two million euros in 2023, according to a study conducted by Statista.

In this context, isothermal packaging plays a key role in the transport of products that need to maintain a specific and constant temperature throughout their distribution cycle, especially for the pharmacy and food sectors, ensuring that the product reaches the end user in perfect condition.

For this reason, the most representative isothermal packages of the target sectors are identified below, making a technical comparison, and the procedure for testing their functionality in maintaining the preservation temperature of the product throughout its distribution cycle is described (climatic test protocol).

Additionally, Itene’s experience in the European project PRIMA SUREFISH is provided as a Case Study, where some of the existing commercial devices on the market are identified to be able to identify if during transport there have been breaks in the cold chain, necessary to guarantee the quality and conservation of fishing products (food sector / pharmacy sector). The results of a cold break simulation will be shown and how the validated devices worked in different locations on the container and pallet.

The isothermal packaging must meet the following requirements:

Storage time and temperature requirements

Technical requirements

Prior to the description of the technical characteristics of each of the isothermal packaging selected by Itene as representative for the maintenance of the cold chain during distribution, the technical requirements to be met by each of the solutions provided are described:

• The isothermal packaging can be single-use or returnable.
• If it is a returnable, it should facilitate its cleaning and disinfection, avoiding hard-to-reach corners.
• The material used must withstand the physical-mechanical level of the distribution cycle used. This requirement refers to the protection from possible shocks or blows during handling and distribution.
• The products that are most sensitive to shocks and shocks during the distribution cycle should be able to be positioned and immobilized, so that they suffer minimal shocks and retain their full quality. Fruits and vegetables are one of the products that can suffer damage during transport.
• It should facilitate the handling by the dealer. Delivery drivers prefer the use of flexible isothermal containers over rigid ones, because the weight and volume of the container are more ergonomic when handling them.
• Although it is expected that most of the food that is transported in the container will come inside a primary packaging, it will be taken into account that the material complies with the current legislation for materials for each of the two target sectors: food and pharmacy.

At some point in the distribution chain, the orders will be transported and handled by the distributor, so the weight of the order should be limited for ergonomics reasons.
The methodology or the cold operation applied with the new container must be implemented with the same ease in all centers. This requirement is important to standardize the company’s isothermal services/packaging and provide the same level of quality.

A water vapor barrier is necessary to prevent water exchanges that may deteriorate the product. In addition, many of the materials used to insulate this type of container lose effectiveness by absorbing moisture.

Possibility of integrating in the isothermal packaging, cold accumulators in pockets or compartments within the same packaging, to help maintain the temperature individually in each of them and not in transport.

Based on Itene’s experience, possible isothermal packaging alternatives existing on the market are analyzed below, based on the technical characteristics of each of its components/materials, which condition its functionality.

Prior to the description of the isothermal packaging, identified as representative in the target sectors, it is necessary to define the two components that will integrate the isothermal packaging system:

• Isothermal packaging: it will avoid the exchange of temperature with the outside allowing to maintain a range of temperatures for an estimated period of time.
• Accumulators: accessories that are kept at low temperatures and constantly bring cold to the isothermal packaging. There are two types, depending on whether you are looking for positive
• refrigeration temperatures (temperatures up to +8 °C are obtained) or negative freezing temperatures (temperatures of -21 °C).

Based on the temperature-time requirements and technical requirements raised, the search has been made for the most representative types of isothermal packaging existing on the market, from which to make a technical comparison, schematized in the following comparative matrix, where it is indicated, for each selected isothermal packaging, the range of working temperatures, materials that compose it and other technical advantages.

In order to validate the functionality of the isothermal packages included in the technical comparison matrix, the following test is proposed for the monitoring of the temperature inside the isothermal package over time under temperature and humidity conditions given by the climatic chamber used in the test. In order to be able to monitor the interior temperature of the packaging for refrigerated and frozen products, taking into account the ISTA 7D profile simulated by the camera, it is recommended to carry out the following preconditions prior to the test:

• Food or simulants: those refrigerated at 4 °C and those frozen at -18 °C;
• Packaging at 23 °C and 50% relative humidity;
• Accumulators, both refrigerated and frozen, at -20 °C.

The selected protocol was the ISTA 7D, because it is one of the most common used when testing commercial isothermal packaging. The following describes the summer profile of this ISTA 7D standard, which could be used to simulate extreme summer conditions.

A data logger must be incorporated in each of the packages. For this, it was taken into account to arrange the sensor so that it was not in contact with the product / simulant or with the accumulators in order to obtain a more accurate and real data of how it will affect the product.

In the SUREFISH project, financed by the PRIMA program of the European Union, commercial tools were selected to control the cold chain, specifically visual time-temperature indicator labels, called TTIs, and devices to measure temperature and humidity, called dataloggers (shown in Table 3). They were tested under simulated transport conditions in the ITENE laboratory in order to evaluate the most appropriate position in a box or loading unit of each type of packaging for fishing products in order to obtain the most appropriate protocols and recommendations to be taken into account in fishing companies that use this type of devices.

The selected solutions were tested in Itene’s simulation laboratories to evaluate the behavior of the existing commercial tools and thus verify the maintenance of the cold chain. Different types of commercial fishing boxes made of different materials were tested, in particular, plastic laminated cardboard, polypropylene plastics, foamed plastic and expanded polystyrene.

The tests confirmed that the boxes used make it possible to isolate the product from abusive temperature conditions. In addition, the products packed in the boxes of the upper layers of the pallet are more sensitive to temperature changes, compared to the products of the lower boxes, as shown by the used cold chain control tools.