Historical information about the spice trade

The trade with spices was and is lucrative. Exotic spices were already seen as a status symbol in Europe at the end of the Middle Ages. By the end of the 15th century, Venetian merchants dominated the spice trade with India and thus acquired great fortunes. At the start of the modern age, precious metals and spices were the reward for those discovering foreign continents. This is how spices like paprika, allspice, vanilla, pepper, cloves, cinnamon and nutmeg arrived in Europe.

These days the cultivation of spices has become globalised. Many are grown in tropical regions around the world because they only thrive ideally in those areas. India appears to largely consume its spice production itself, as it is less significant as a supplier to the German market – but increasingly so in the United Kingdom. Consequently, today Europe imports pepper mostly from Brazil (2020: 45%) and Vietnam (37%). Smaller quantities come from Indonesia and Cambodia. Germany buys cinnamon from Madagascar (2020: 30.7 per cent), Indonesia (26.7 per cent), Vietnam (16.7 per cent), Sri Lanka (10.9 per cent) and China (8.8 per cent). In contrast, it is also possible to grow paprika in Europe. 38.8 per cent of supplies came from Spain in 2020. Spain is the largest paprika producer and processor in the world, with many dried paprika derivatives that are used as colourings and flavourings coming from Spain. For the next decade, growth among organic herbs and spices is expected, accompanying the trend towards organic food.

Sustainable spice trade

When it comes to importing spices, all aspects surrounding the issue of sustainability are becoming increasingly important. Not only environmental protection in terms of cultivation plays a part here, but also the requirements from German supply chain law.

„The Codex Alimentarius is a collection of internationally recognised food standards. It is based on the approvals and resolutions of the so-called Codex Alimentarius Commission, a joint body of the Food and Agriculture Organisation (FAO) and the World Health Organisation (WHO) set up by the United Nations.“
(Source: German Federal Ministry of Food and Agriculture – BMELL)

Founded in 1963, the Codex Alimentarius (CA) is supported worldwide by approx. 190 members. In 2003 the EU also joined the CA, meaning that its rules also apply to spices in Europe. Typical quality controls extend among other things to:

  • examining the spices for microbiological risks
  • checking the legal requirements relating to plant protection
  • labelling accuracy - protection against fraud
  • random sample checks using statistically determined specifications in the producer country and at the recipient before further processing
  • operational establishment and implementation of a HACCP concept
  • sanitary measures in case of gross deviations from the rules

Contamination can degrade spices very rapidly. This also includes small organisms. To prevent infestation, prior to shipping or storage, spices are subject to a disinfestation process or protective treatment with CO2 (carbon dioxide) or PH3 (hydrogen phosphide).

Microbiological contamination cannot be ruled out on the other hand. There is no such thing as germ-free spices. Yet there are thresholds for the microbial counts and standard measuring methods for determining them.

Mould fungi can secrete particularly poisonous mycotoxins and aflatoxins. Coli bacteria and salmonellae such as streptococcus, staphylococcus, clostridium, pseudomonas or enterococcus are also harmful.

First-class spices are grown in tropical and subtropical countries. The air humidity and heat found there can propagate a bacterial infestation explosively. The best spice qualities require that their attack by bacteria is low or / and reduced early enough. Specific heating using steam sterilisation in an autoclave and subsequent vacuum sterilisation are standard treatment methods.

Arriving directly from the sea container, the spices are subject to further tests and cleaning operations. Product-specific parameters for the quality control of individual spices are provided by the European Spice Association (ESA). Essentially these include

  • Varietal purity
  • Bacterial infestation
  • Analysis of chemical substances
  • Content of essential oil
  • Smell and taste intensity
  • Oil and water content
  • Granulometric characteristics
  • the optical appearance and colour
  •  Authenticity of the accompanying documentation

How spices are cleaned

Basically, one must distinguish between mechanical cleaning processes and disinfestation / sterilisation processes.

The mechanical methods include

  • washing and soaking,
  • sieving and screening (classifying) and
  • the use of metal cutters

Depending on the spice, washing and soaking is one of the first cleaning steps, for example to remove soil and sand from root and rootstock spices. For some spices, the crops also need to be soaked to obtain the desired raw product. This is the case, for example, with white pepper, which is produced from pepper berries shortly before they turn red and is soaked for around eight days in softly flowing water. For cleaning processes with water, it is important to thoroughly dry the product immediately afterwards.

The sieving and screening process is used to separate uneven particles and serves two task areas in spice production

Flat screens, vortex screens and tumbler screens classify the spice particles according to size. Aspirators, centrifugal and wind sifters separate spice particles according to different densities.

The above-mentioned separation processes are used on one hand for raw material input control and on the other hand as classifiers within the grinding plants.

Sterilisation is health protection

Spice sterilisation and disinfestation is health protection. The sterilisation methods include(d):

  • Gassing with ethylene oxide, ozone or carbon dioxide
  • Heating for example with steam, microwaves
  • Exposure to ionising radiation

Criteria for the selection of suitable finishing methods are always the sensitivity of the spice and its components, the required reduction of the microbial count and the subsequent use. Some of these methods are subject to labelling, for example radiation treatment. Others did not get beyond the test stage and some others are banned in the EU. Table 6 provides an overview.

The large number of methods shows that the sterilisation of spices is complicated. The aim of killing off micro-organisms conflicts with the requirement to protect substances in the spices such as essential oils, vitamins and flavours.

Table 6: Various sterilisation options with advantages and disadvantages and their practical significance 

Auxiliary material
Carbon dioxide (CO2)
+ permitted under food law aspects

+ suitable for disinfestation (insects that damage stocks)
- for sterilisation, the application under pressure (40 bar) is not adequate. Effective sterilisation is only expected under high pressure.

+ safe in terms of food law

+ highest heating and hence affects the product surface
- Trade-off between product preservation and sterilisation result to be achieved
Suitable for whole and ground spices as well as herbs
+ safe in terms of food law
- Success dependent on water content

- The effect is weakest on the product surface (can be improved by wetting)

- High thermal stress to the product and hence sensory impairment of the quality.
Not suitable for products with a water content below 5 %.

Has not proved very effective in practice.
Infrared light
+ safe in terms of food law

Gamma rays / X-rays / electron rays

- subject to labelling
Not for organic spices.

Spices sterilised by radiation are also approved for consumption in the EU, but subject to labelling. Ionising rays such as gamma rays, X-rays or electron rays may be used. Sterilisation with ionising radiation is ruled out for organic spices. The equipment used for sterilisation by radiation must meet special requirements and be approved and monitored by the respective state authorities for the Federal states, for instance the German consumer advice centre.

Sterilisation by means of infrared light

According to the literature, infrared light is supposed to effectively sterilise leaf-based spices such as parsley, but also cumin, vanilla, pepper and chili. The even heating with finely adjustable process temperature kills off salmonellae, mould fungi, E. coli and enterobacteriaceae among others. The bacterial count can be significantly reduced in this way.

Steam sterilisation as a decontamination method

For the steam sterilisation process under vacuum, the air is first completely extracted from the container where the spice is located. The product is then heated up and then exposed to saturated steam over a defined period. The steam condensate is then removed and dried by vacuum application. Finally, the container is returned to atmospheric pressure with sterile air.

Because, depending on the raw material, many process parameters need to be observed for this method of sterilisation to clean the spice as gently as possible, therefore some companies have specialised in providing sterilisation as a service. In each case their expertise is their own method for achieving optimal results. In addition, plant manufacturers supply suitable machines for sterilising with steam, meaning that spice manufacturers can also perform this cleaning step in their own production.

Dried spices last longer

If the spices have a low microbiological contamination level, then it is important to store them in hygienic and dry conditions.

Food technologies differentiate between the water content and activity of water (aw content).
The latter influences the growth of micro-organisms

The water content after harvesting is around 80 per cent. Spices only have good storage properties if the aw content is around 10 per cent. Drying spices is energy-intensive and expensive; especially when the drying process has to be done gently at low temperatures – the weight decreases with increased drying level – and hence the price for the crop size. In this respect, fair regulations between the producer and buyer are required.

Fine particles, precise dosing and mixing, intense taste

Not all spices are ground. Sifted spices – for example bay leaves – remain completely intact. Sometimes parts of plants are initially cut, then destemmed, which means the stalks are removed. In contrast, seeds or fruit spices in particular are often ground.

Grinding spices means increasing the surface area

Large surface areas open up more aroma and taste, which requires a fine grinding level. Critical for the quality of the spices is that the crushing process is gentle. The expulsion of atmospheric oxygen and the supply of supercooled inert gases enhances quality but is expensive. Cryogenic grinding methods are applied beneficially in case of nutmeg, pepper, ginger, cardamom or cloves. The use of nitrogen/ liquid nitrogen also reduces risks of a dust explosion.

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