Shipping food chilled: the practical guide to cold-chain parcel shipping

Shipping meat, fish, cheese, ready meals or dairy chilled with a standard parcel carrier is perfectly doable, provided that packaging, cooling and planning are matched to each other. A parcel easily spends 24 to 48 hours in transit, in a sorting centre or delivery van where temperatures can rise well above 25 °C in summer. This guide explains step by step how to ship food chilled: which cool box to choose, how much coolant you need, how to pack and what to look out for with the carrier.

1. What temperature must your product hold?

Always start with the product, not the box. Roughly speaking, there are three temperature zones:

• Chilled (2 to 7 °C): fresh meat, fish, dairy, ready meals and fresh pasta. Most food shipments fall into this category.
• Frozen (−18 °C or colder): ice cream, frozen meat, frozen fish and frozen meals. This requires the heaviest insulation and the most cooling.
• Cool and dry (8 to 15 °C): chocolate, whole pieces of cheese, wine and certain bakery products. Here the focus is mainly on protection against heat.

Define the limit that must not be exceeded and the maximum transit time, including a one-day delay. With those two figures you can choose the packaging.

2. Choosing the right cool box

EPS box (polystyrene)

The EPS box is the standard for shipping food chilled. EPS insulates well, weighs almost nothing, does not absorb moisture and is suitable for direct contact with food. A thick-walled EPS box with sufficient cooling elements stays below 0 °C for around 30 hours and below 8 °C for up to 48 hours at an outside temperature of 25 °C. For meat and fish that produce meltwater, choose a box without drain holes, or a box with drain holes if the products are resting on ice.

Foldable thermal box

A foldable thermal box consists of a cardboard outer box with a separate 4 or 6-layer insulated liner bag. The box is delivered flat: up to 5 times as many fit on a pallet compared with EPS. That saves storage space and inbound freight. With the 6-layer bag you reach 48 to 72 hours. For webshops with many shipments and little storage, this is often the smartest choice.

Insulated bag

For small or flat shipments, such as a few pieces of meat or a meal for one day, an insulated bag in a standard shipping box is often enough. Inexpensive and light, but with a shorter cooling time than EPS or a foldable thermal box.

Not sure between two options? Read Foldable thermal box or EPS box: which suits you? or view all cool boxes at a glance.

3. How much coolant do you need?

The box insulates, but it does not cool. The cold comes from gel packs or rigid cooling elements. A reliable rule of thumb:

• Chilled, 24 hours: 400 grams of gel pack per 5 litres of box volume.
• Chilled, 48 hours: double that, so 800 grams per 5 litres.
• Frozen: also double, with the gel packs fully frozen at −18 °C.

Example: a 20-litre EPS box for chilled meat that is in transit for 24 hours needs 4 gel packs of 400 grams. If the same shipment has to last 48 hours, use 8 or choose a thicker wall. The full calculation method is in How many gel packs do you need per shipment?

Note for chilled products: a deep-frozen gel pack placed directly against fresh meat, vegetables or dairy can cause freezing damage. Put a layer of cardboard or paper in between, or use chilled instead of frozen packs.

4. How to pack the box

1. Pre-cool everything. Product at its final temperature, gel packs lying flat and separate from each other in the freezer for at least 24 hours. A cool box holds temperature; it does not make anything colder.
2. Pack the product leak-proof. Vacuum-packed or in a sealed bag, so that moisture and odour stay inside.
3. Place coolant at the bottom and on top. Cold sinks, so the packs on top do most of the work.
4. Fill empty space. Air means heat exchange. Preferably choose a smaller box that ends up full.
5. Close the lid or bag completely. Tape the lid shut all the way round and preferably place an EPS box inside a cardboard outer box.
6. Label clearly. State "Keep chilled" and add an arrow pointing up.

A detailed example for meat: Shipping fresh meat chilled.

5. Carrier and planning

Not every carrier accepts perishable food in its standard network. Check the terms of your parcel service and, where possible, choose a next-day delivery service. A few fixed rules:

• Ship from Monday to Wednesday, so that a shipment does not sit in a depot over the weekend.
• Plan for the longest route, not the average delivery time.
• Pack more heavily in summer: extra gel packs or a thicker wall.
• Let the recipient know that a chilled parcel is on its way.

6. Regulations in brief

Anyone who ships food professionally is responsible for the cold chain right up to the customer's door. The packaging must be suitable for food contact and the temperature must stay within the limit that applies to the product. Therefore test your packaging once with a temperature logger on the longest route, in the warmest period. Then you know for certain that your set-up works.

Frequently asked questions

How long does food stay cool in a cool box?

With a thick-walled EPS box and enough gel packs, up to 48 hours below 8 °C at an outside temperature of 25 °C. A foldable thermal box with a 6-layer insulated bag reaches 48 to 72 hours.

Can I post frozen products?

Yes, with a thick-walled EPS box or a foldable thermal box with a 6-layer bag and double the number of fully frozen gel packs. Preferably keep the transit time under 24 hours.

Which is cheaper: EPS or a foldable thermal box?

Per unit, EPS is often slightly cheaper. The foldable thermal box wins on storage and inbound freight, because it is delivered flat.

How quickly can I receive packaging?

All standard sizes are in stock. Ordered before 14:00, shipped the same day.

Cooled Solutions has manufactured cold-chain packaging in its own production since 1972. View the EPS boxes, foldable thermal boxes and gel packs, or request a sample to test your own route.