How to reduce food waste

The Corona pandemic and the war in Ukraine have exposed the fragility of global supply chains: price jumps and supply bottlenecks for fertilisers, as well as a shortage of individual food products (such as cooking oil). Just a few years ago, hardly anyone would have imagined such a situation. At the latest since the Corona outbreak in early 2020, regional food production as well as a secure supply of healthy and safe foodstuffs have regained importance. On the one hand, the demand for food is facing limited world resources and a rising global population. On the other hand we have the need for action on climate protection and sustainability. This makes it all the more obvious that we have to use the resources at our disposal responsibly and avoid unnecessary losses.

More than 40% of food waste is caused by the end consumer and can be avoided or at least reduced through proper food storage and better knowledge of its shelf life. For example, it is important to distinguish between the date of minimum durability (“best-before date”) and the use-by date. Perishable foods are marked with the latter and must not be consumed after this date (potential health hazard!). Less sensitive foods, on the other hand, have a date of minimum durability or “best-before” date. This merely specifies the date by which the manufacturer guarantees the defined properties (sensory, visual, etc.) of his product as a minimum. Often these products can still be consumed for some time after the best-before date has expired – provided there is no discernible change in appearance or taste.

The causes of food spoilage can be roughly divided into four categories: physical or chemical spoilage, pest infestation or microbiological spoilage. The first two are processes such as dehydration or oxidation, which primarily have a negative impact on sensory properties, whereas damage to food caused by maggots, mice or similar is usually visually recognisable. Microbial spoilage of foodstuffs caused by bacteria, yeast or mould is much more common and often more insidious because sometimes it is hard or impossible to identify. Microbial processes are responsible for the majority of food spoilage in easily perishable foods (animal-based foods, fresh vegetables, etc.) and should therefore be avoided at all costs based on the following considerations. Most moulds can produce very potent toxins, which spread rapidly throughout the product and can lead to severe acute or chronic health damage. As the toxins are usually heat-stable, neither cooking nor heating will help. Mouldy food should therefore usually be disposed of completely.

In general, foods that don’t need to be refrigerated, such as flour, rice, pasta, onions, etc., should be stored in a dry (protection against mould) and cool (usually around 18 °C is ideal) place as well as protected from light (this prevents the germination and destruction of valuable, light-sensitive nutrients).

With a few simple tricks, the shelf life of refrigerated food can be considerably extended and premature spoilage prevented. In most fridges there are different temperature zones. It is generally coldest in the lower area directly above the vegetable compartment and warmest in the upper area or the fridge door. Perishable foods such as fish or meat should be stored as cool as possible; less sensitive products such as butter or eggs can be stored in the upper, less cold section of the fridge. Before opening, milk should not be stored in the door but in the lower part of the fridge. Fruit and vegetables belong in the crisper drawer – in addition to the cold temperature, they are also more humid, which prevents these foods from drying out. However, this drawer is not suitable for other foodstuffs; there is a risk of mould due to the high humidity. Also, not all fruits or vegetables are suitable for storing in the fridge.

As with other food supplies, the “first in, first out” principle should also be applied in the fridge. Older products should always be consumed first; ideally, the foods with the longer shelf life should be placed towards the back of the fridge and older products towards the front.

We’ve all been there: far too much grilled food is prepared at a party or salads stand unrefrigerated at the buffet all evening and are ultimately inedible... However, it is very easy to significantly reduce food waste (and thus costs):

• It should be arranged in advance whether guests will bring dishes, salads or desserts and, if so, for how many people.

• Barbecue food should be prepared “to order” and only then be taken out of the fridge.

• Salads should be prepared in appropriate quantities and/or served buffet style.

• For larger events, a cold food buffet can be advantageous.

It should also be noted that, especially in midsummer, room temperature is often not ideal for storing foods that don’t need to be refrigerated. In this case, it is advisable to store these in a cooler (but dry!) place such as a cellar. In addition, special care should always be taken to maintain the cold chain, for example when taking home frozen or chilled foods from the supermarket..