To ensure that fruit, meat, vegetables and other temperature-sensitive foods not only remain edible after days of transport, but also look pretty, logistics specialists must maintain the so-called cold chain: guaranteed at the right temperature from production through storage and transport to retail and the end customer. We show how refrigeration is currently ensured in food transport. We also take a look at the difficulties companies face and the regulations that apply to the food cold chain.

Cooling in food transport

Refrigerating temperature-sensitive foodstuffs during transport is a logistical feat: every handling point is a potential risk, incorrect airflow in the refrigerated truck can lead to freezing damage, and if the cold chain is interrupted for too long, the goods become unusable in the worst case. To protect consumers from damage to health caused by improperly refrigerated products, there are a number of regulations and legal requirements that must be complied with during transport.

Maintaining the cold chain

The basic prerequisite for temperature-controlled logistics is compliance with the cold chain. The cold chain refers to the continuous cooling of foodstuffs during transport between the manufacturer or producer, wholesaler and supermarket/retailer. As a rule, temperature-sensitive foods pass through the following four stations on their way from production to the refrigerator or freezer:

• Production/collection: The first critical point is collection from the manufacturer. Depending on the length of the transport route, the products change from the manufacturer's (freezer) cold rooms to actively or passively refrigerated transport vehicles.
• Storage/wholesale: A temperature lock is normally available for intermediate picking in the central warehouse. After picking, the foodstuffs go to the (frozen) cold storage.
• Transport/retail: Via refrigerated transport, the foodstuffs start their journey to the retail trade. In supermarkets, where intermediate storage is not possible, the products are packed directly. Here, there is a risk of interruption of the cold chain, especially in summer.
• Delivery/end customer: The transport between retail and end consumer is also known as the "last mile" and represents a particular challenge for cold chain logistics because it is very difficult to plan.

The HACCP concept & the food cold chain

The HACCP concept(HazardAnalysis and Critical Control Points) is a quality management system valid throughout Europe for the production and handling of food. In Germany, it has been included since 1998 in the Food Hygiene Ordinance since 1998. Among other things, the concept provides for ahazard analysis and identification of the critical control points for food safety.

Refrigeration in food transport is such a critical control point: the HACCP concept stipulates that the temperatures indicated on the food packaging must be checked regularly, and that maximum or minimum values must be specified. In addition, according to HACCP, complete documentation of the measured temperatures is required in order to be able to prove continuous refrigeration (more information on the obligation to monitor temperatures).

The temperatures to be maintained during food transport are determined by the manufacturer or the legislator. In the case of processed ("finished") food, the manufacturer specifies the required temperature range. If it is raw goods, certain temperatures must be maintained by law. For example, poultry may not be transported above +4 and minced meat above +2 degrees Celius.

The HACCP concept in frozen food transport

Since different conditions apply to the production and transport of frozen foods than in the "simple" cold chain, the HACCP concept was expanded in 1978 to include corresponding regulations for frozen foods. In the frozen food sector, the concept for food transport provides for cooling to -18 degrees Celsius. Deviations of more than +/- 3 degrees Celsius are within the tolerance range; in the event of greater deviations, the cold chain is considered interrupted.

Since the 1990s, the legislator has also recommended the use of so-called time-temperature indicators for the transport of foodstuffs in the frozen food sector. These are intelligent indicators attached to the packaging of the transported goods, which indicate a critical change in temperatures by means of color changes.

Our blog article "HACCP concept & guidelines for refrigeration" explains all legal regulations relevant for cold chain logistics in detail.

Difficulties of cold chain logistics

The HACCP concept makes complete documentation of the cold chain mandatory. However, compliance with the cold chain on paper is no guarantee that the temperature-sensitive items have actually been cooled correctly. Currently, there is still a lack of binding regulations on where and how the temperature of the goods is to be measured.

Although the Foodstuffs Ordinance refers to "product temperature", in practice temperatures are not normally measured inside the products, but only on the respective transport packaging or at most on the product packaging . However, this value has little significance for the product temperature because it merely indicates the room temperature prevailing in the respective refrigeration zone (e.g. in the hold of the refrigerated truck).

Even time-temperature indicators, which are generally considered to be very safe, only measure the temperature on the packaging to which they are attached or stuck. If this temperature rises above the respective maximum value, the label discolors. Temperature measuring strips have the advantage that they cannot be manipulated (the discoloration remains visible even if the temperature later returns to the acceptable range). At present, however, they are not yet ideal for monitoring refrigeration in food transport:

• Too time-consuming: The temperature measuring strips can only be activated individually, which is time-consuming.
• Too large: For smaller transport boxes, the stickers on which the temperature measurement strips are located are often too large.
• Too inaccurate: Since the indicators react to external influences such as light and hand heat, incorrect results cannot be ruled out.
• Too expensive: Temperature measurement strips are relatively expensive and are therefore currently only used in the transport of expensive medicines and foodstuffs.

Food transport over very long distances

Refrigeration in food transport over very long distances is a particular challenge: When the beef from Argentina or the quinces from Turkey arrive at their destination, they have often already spent many days in trucks or container ships. In order to be able to guarantee continuous cooling (and thus the quality of the food), companies basically have a choice between two different systems: active cooling and passive cooling.

For long transport distances , however, passive cooling by means of cooling elements and dry ice is not practical. For this reason, the foodstuffs are actively cooled during transport over very long distances: particularly powerful power supply units, so-called GenSets, also known as generator sets or container generators, are used here.

Longer waiting times at border crossings or kilometer-long traffic jams are usually no problem for refrigeration in transport vehicles equipped with container generators.

Disadvantages of active cooling in food transport

Active cooling systems have a firm place in cold chain logistics - and not just because they ensure refrigerated transport over very long distances: they are reliable, effective, and many solutions have integrated automatic recording of temperature and humidity data. Nevertheless, retail and logistics companies have to contend with some difficulties when it comes to active refrigeration in food transport:

• High cost: Power supply units are expensive to purchase and costly to operate.
• High damage amounts: Even the smallest shunting damage can result in costly repairs for actively cooled transport vehicles.
• Not sustainable: Since the power pack significantly reduces the range of the traction battery, actively cooled transport in electric vehicles is currently not yet an option, especially on long distances.
• Environmentally harmful: Trucks in which the refrigeration unit runs on the diesel engine produce considerable_{CO2 emissions}(more information about _{CO2 emissions} in food transport).

Passive cooling in food transport

At passively cooled transport of foodstuffs, no power unit is required: The actively refrigerated hold or container is replaced by the insulating packaging, which keeps the goods within a certain temperature range during transport.

In addition to insulating packaging, retail and logistics companies use cold packs and/or dry ice are used. Passive cooling has the following advantages over active cooling in food transport:

• Lower costs: Transport in non-refrigerated vehicles is significantly more cost-effective than classic refrigerated transport. A further reduction in costs is possible if companies opt for reusable solutions for insulated packaging.
• Lower risk of damage to the goods: freezer burn, which can occur in refrigerated trucks, for example, due to inadequate airflow, is not normally a problem during transport with insulated packaging.
• Better environmental balance: Passively cooled food can be transported in electric vehicles without any problems, as the cooling does not depend on the traction battery.

Disadvantages of passive cooling in food transport

Companies that rely on passive cooling for transporting food can plan more flexibly and save on investments in elaborately upgraded refrigerated vehicles. However, conventional passive cooling solutions only keep products in the required temperature range for a very limited time: most systems can only provide constant cooling for a few hours. Depending on whether the cooling capacity is supported by dry ice and disposable insulating packaging is used, there is also a high environmental impact due to packaging waste and released_CO2 (more information).

Cold chain logistics with temprify

As an expert in passive cooling for food transport, temprify developed temprify develops the right infrastructure for each link in the cold chain. We solve the problems of conventional refrigeration systems with technical innovation and transform refrigeration logistics challenges into sustainable, scalable products. Our (freezer) coolers for food transport guarantee continuous cooling for up to 96 hours and our tempriRacks replace the refrigeration unit in refrigerated vehicles.

Our cooling solutions work without a fixed power unit, without dry ice and without packaging waste. We achieve maximum cost efficiency by using our proprietary pre-cooling infrastructure is compatible with all temprify cooling solutions. In this way, our customers can reduce their costs and at the same time contribute to the energy transition.

Click here to go to the one-stop store for sustainable, cost-effective cooling solutions!