Can tea bags expire? (+3 Ways to tell)

In this article, we will answer the question “Can tea bags expire?”, and how to tell If the tea is bad?

Can tea bags expire?

Tea bags do not necessarily have an expiration date, but rather a best-before date. In other words, the date you see on labels shows when the tea hits its peak quality, after which it will start to decline. As a general rule, tea lasts up to 2 years [1].

If properly stored, it is very unlikely that microorganisms will grow in tea, even after two years of storage, or that you will get sick from consuming that tea, because the development of fungi and bacteria is inhibited by the tea’s low content of water [2].

What happens with expired tea bags? 

A number of studies have found that tea leaves undergo chemical changes over time, losing aroma, freshness, and beneficial compounds [2,3]. 

In a study on herbal leaves [2], the authors observed a significant drop in antioxidant properties after 120 days of storage in a dry, dark place, at ambient temperature. 

From these findings, the authors concluded that long-term exposure to oxygen may have promoted some oxidation of tea compounds. 

In another research [3], green tea leaves stored at 4 °C or ambient temperature faced critical freshness loss after 100 days of storage. 

Thus, even if your tea looks pretty good after the best-before date, its flavor, freshness, and benefits may have been significantly modified, becoming unsatisfactory. 

Can an out-of-date tea make you sick? What are the risks?

It´s very unlikely that you get sick from consuming expired tea. The moisture content of tea is 5% or less, and the water activity (amount of water available in foods for microbes to grow) is also at microbiologically safe levels (<0.6) [4].

Moreover, tea is rich in substances that can inhibit some microorganisms. All of this makes tea a very hostile environment for dangerous microorganisms’ growth, even after the best-before date. 

It just won’t be as flavorful as it was before the expiry.

But note that this is true only for correctly stored teas. According to recent studies [4, 5], tea carries a rich flora of bacteria and fungi derived from the cultivation, processing, and manipulation steps. 

These microorganisms remain inhibited due to the low water content, but if tea is exposed to high humidity ambients (>60 %) and absorbs moisture, microorganisms can find favorable conditions to grow.

My recommendation is that you throw out tea at any sign of humidity.

But if you decide to drink any old tea, prepare it by brewing it with hot/boiling water to ensure the elimination of vegetative pathogens (e.g. Salmonella spp.) potentially present in the product.

Viegas and others [5] proved that boiling reduces substantially tea contamination.     

How to tell if the tea bag has gone bad?

Although tea does not expire, depending on the storage conditions, its quality can drop. To know if your tea is gone, examine these items:

• If the tea appears wet, or clumpy, discard it, because humidity may have favored the development of microorganisms.

• If the tea exhibits cotton-like spots, it might indicate the growth of molds. This tea must be disposed of immediately.

• Tea has to smell like the day you bought it, otherwise, it can be oxidized. Although it can not harm you, its taste can be very unpleasant. 

• Look for the signs of any insect. If you see something moving in the tea bag or if the tea bag has tiny holes in it, throw it out.

• Tea bags should not appear wet or damaged. If so, be careful with the other spoilage signs.

How to store tea bags safely?

• Always store your tea in a cool place or at room temperature. Keep it away from the stovetop and sunlight. 

• Keep your tea in a sealed package or an airtight container. Do not let it come in contact with the air frequently. Air will remove the volatile compounds of tea and deprive it of its aroma and flavor.

• Keep your tea container in a dark place preferably in a cabin.

• Do not let water get into your tea pack.

Conclusion

In this article, we answered the question “Can tea bags expire?”, we also discussed what happens with tea after its optimal shelf life and how to tell If the tea has gone bad.

Citations

1. Motarjemi Y, editor. Encyclopedia of Food Safety. Waltham: Academic Press; 2014, pp. 371-383.

2. Guimarães R, Barreira JCM, Barros L, Carvalho AM, Ferreira ICFR. Effects of oral dosage form and storage period on the antioxidant properties of four species used in traditional herbal medicine. Phytotherapy Research. 2011;25(4):484-92.

3. Dai Q, Liu S, Jiang Y, Gao J, Jin H, Zhang Y, Zhang Z, Xia T. Recommended storage temperature for green tea based on sensory quality. J Food Sci and Tech. 2019; 56(9): 4333-48.

4.X. Zhang, L. Zhang, T. Zhou, Y. Zhou, Fungal flora and mycotoxin contamination in tea: Current status, detection methods and dietary risk assessment – A comprehensive review, Trends in Food Science & Technology, 127 (2022) 207-220.

5. C. Viegas, F. Sá, M. Mateus, P. Santos, B. Almeida, L. Aranha Caetano, A. Quintal Gomes, S. Viegas, Commercial green tea from Portugal: Comprehensive microbiologic analyses, International Journal of Food Microbiology, 333 (2020) 108795.