Tea as food - safety through analysis, and checks on origin and authenticity
Did you know that both tea and the tea bag were accidental discoveries?
According to Chinese tradition, on a spring evening in 2737 B.C., Emperor Shen Nung was fortunate enough to enjoy the very first tea when the wind blew some leaves into his cup of freshly brewed water. The invention of the tea bag over 4,500 years later was similarly coincidental, when the American tea trader Thomas Sullivan actually only wanted to save postage. He no longer packed his tea in tin cans but in small silk bags which his customers then simply dipped directly into hot water.
In order to ensure quality and safety for tea connoisseurs today, one does not rely on chance. Companies in the food industry independently install control mechanisms with effective and well-documented systems which also take into account the movement of goods across national borders. With different instruments, from risk analysis to origin and authenticity checks, as well as laboratory analyses, we jointly face the important task of food safety.
It begins with the definition: tea as food
Tea is the second most consumed beverage in the world after water. Every German drinks about 28 litres of tea a year. But what exactly is meant by the term “tea”?
The guidelines of the German food code define tea and tea-like products as follows:
- Tea: prepared leaf buds, young leaves and young shoots of the tea bush (Camellia sinensis). After fermentation, these include green and black tea.
- Tea-like products: this includes herbal and fruit teas, dried parts of plants such as leaves (mint), fruits (apple), flowers (hibiscus), bark (Rooibos) or roots (liquorice).
The origin plays an important role: tea in cultivation
It is a long way from the green leaf on the tea bush to the cup: picking, drying, fermentation, sieving, rolling and packing. In food risk assessment, the origin of the raw materials plays a particularly important role as individual problems can arise depending on the growing region. In addition to product quality, compliance with social standards in the countries of origin is also very important for EU importers.
The most important tea growing countries are India, Kenya, Sri Lanka, Indonesia and China. Many tea varieties originate from specific growing areas within these countries and hence receive their name. Some of the best known examples:
Darjeeling is a growing area at an altitude of 2,000m in the Himalayas in northern India. Darjeeling tea is one of the highest quality and most expensive tea varieties. For years there have been repeated strikes by the Gorkhas who settled there for work and who wish to have better living and working conditions.
Ceylon is now Sri Lanka, an island state on the eastern southern tip of India. Formerly the largest tea producer in the world, Sri Lanka reduced its production due to political and economic setbacks and thus lost its leading world market position.
Assam is a plateau on the Brahmaputra in northeast India and the largest contiguous cultivation area in the world and already looks back on a tradition of over 160 years. The workers and their families have in many cases lived directly on the plantations for several generations.
Customers and companies want to be sure that both the product and the conditions for the tea farmers are as good as possible. To ensure these standards, individual supplier audits, on-site sampling, loading controls and laboratory analyses are carried out, among other things.
A look inside for more certainty: tea analysis
As with all foods, quality, authenticity and safety play an important role in tea. In order to meet the legal requirements as well as the demands of the consumers, sensory, optical and chemical controls are carried out with the help of food testing both directly in the countries of cultivation and in Germany.
In chemical control, quality-giving parameters are examined, such as the proportion of essential oils, the dry matter or the caffeine content.
In microbiological tea analysis, the aim is to determine the hygienic status and the certainty that no pathogenic microorganisms are present in the tea.
In addition, the product is checked for environmental contaminants (e.g. heavy metals or pesticide residues). The sample is also analysed to see whether it has been treated with irradiation.
Product typical challenges
To ensure food safety, there are numerous regulations and rules in the EU. Important regulations from this area for companies in the tea industry include the residue and mycotoxin maximum quantity regulations, as well as various regulations on contaminants, pesticides and food hygiene. The focus of the tea analysis here is primarily on residues of pesticides, PAHs and pyrrolizidine alkaloids.
Tea analysis: plant protection products and PAHs
Controls for tea usually focus on residues of various pesticides and PAHs (polycyclic aromatic hydrocarbons). PAHs are formed during combustion processes and can enter the tea during drying but also, for example, from forest fires.
Tea analysis: pyrrolizidine alkaloids (PA)
In the analysis of tea, the pyrrolizidine alkaloids (PA) have become the main contaminants in recent years. They are natural toxins that occur in about 6,000 plant species, especially in angiosperms. They enter the tea through PA-forming herbs in the fields or through accidental co-harvesting. PAs can damage the liver; they are considered to be mutagenic and carcinogenic. Currently there are no PA limits, but a maximum intake.
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