What can Greentest do?

Greentest nitrate tester can measure nitrate levels in fruit and vegetables, whether they contain any harmful substances, by determining the relative concentration of nitrate ions. Greentest3 with TDS meter function can measure the concentration of various salts in water. Greentest ECO measures the power of ionizing radiation (gamma-ray and beta-particle flux) to determine background radiation which can be found all around us in a variety of commonly used objects construction materials, household devices, office accessories, etc).

What kind of contaminants are measured by Greentest? Can Greentest detect heavy metals, pesticides and other harmful substances?

Greentest measures the salts concentration in the tested products and water, both salts that are essential and the ones that can cause serious harm to your health. This is especially true for nitrate salts that can accumulate in food products in high concentrations, due to improper cultivation. Greentest is calibrated to show the number of nitrate ions only.

The device is not intended to detect pesticides and heavy metal ions, as they don’t influence the electric conductivity.  However, he high level of nitrate content found within food products may have a link to higher levels of pesticides, heavy metals, and link to lower levels of antioxidants, microelements and vitamins.

Does Greentest TDS meter measure the pH level of water?

Greentest does not measure the pH level in water, Greentest TDS meter measures the concentration of various salts, solids and acids disolved in water. High molecular organic compounds such as pesticides, herbicides and hydrocarbons cannot be detected by the device. Greentest scale is calibrated in ppm parts per million (ppm) and it determines the amount of foreign ions for 1 000 000 molecules of water. That is why 1 ppm=1 mg/l=0,02 mg-equivalent/liter = 0,01 mM equivalent/liter. (Based on norms provided by the German Institute of Standartization DIN19643).

Can Greentest measure water hardness in flowing water?

No, the measurements can only be conducted in constant and stable water. During measurement, it is important to hold the proble steady and completely submerged in the water.

Can Greentest indicate the freshness of fruit and vegetables?

Greentest can detect the content of nitrates in fruit and vegetables. It is common for some fruits to be stored in the refrigerator for months after harvesting, or with preservatives and chemicals added to make them look fresh. High levels of nitrates may indicate the fruit is not fresh enough, because nitrate ions within the plant cells will gradually be released during storage as the fruits start to decompose. When food is not fresh, nitrate levels tend to rise. Freshness is related to the potential bacteria/fungus level, a matter of hygiene and food safety.  Therefore, Greentest does not directly indicate “freshness”, but by knowing the nitrate level in fruits and vegetables you may make a more informed conclusion on whether they are fresh enough or not.

What kind of meat does Greentest test?

Greentest nitrate tester can measure the freshness of all types of meat, including fish and poultry.

What kind of background radiation does Greentest detect?

Background radiation is determined by the amount of power ionizing radiation (gamma-ray and beta-particle flux), which are the most harmful to human’s health). GreentestEco devices are the only devices available that detect background radiation within the measurements recommended by international standards.

Why is the radiation indicator sound always on?

GreenetstEco starts measuring the background radiation immediately after the device is switched on. It will stop detecting radiation only when the device is switched off. In case of high level of background radiation, the indicator will produce a frequent sound. The result of the ionizing radiation test will be displayed and a recommendation will be issued. Who knows, maybe one day, GreentestEco will save your life.

What is a cumulative dose?

A cumulative dose is the maximum dose accumulated during the whole time needed for the radiation detection process. To start measuring the cumulative dose, press the START-STOP button on the screen. The device continues measuring in the background until the measurement is finished by pressing the STOP button. To clear previous readings, use the Reset button.

What does the Green, Yellow and Red colors results indicate?

The norm (indicated by the green color) for every type of food product has been provided based on European, American and Asian standards and recommendations (references are provided in the user manual – section 1.4). The yellow and red indicators are based on the recommendations of scientists and research from health organizations (this is more of a suggestion than a strict rule to follow).

What to do with a product that has a red color result? Cook, eat, or throw away?

We do not advise you to throw away food products if Greentest shows a red result, we only claim that if you consume all vegetables with a high nitrate concentration for long periods then it will raise the risk of particular diseases, thus consumers are recommended to calculate their daily intake compared to their <insert the full term for ADI> (ADI).

A red color result should help you to determine where to buy your food products and whether it is the right time/season to buy these products.

Mainly fruits do not pose a significant threat due to relatively low nitrate content. As for vegetables there is usually no need to throw away high nitrate concentrated vegetables as some cooking and preparation procedures can lower nitrates by 15‐60%. To reduce the risk of high nitrate concentrated vegetables we recommend that you:


  • Store leafy vegetables in a refrigerator if they are not cooked immediately;
  • Cook vegetables soon after chopping or mashing;
  • Wash and peel vegetables before cooking;
  • Blanch high‐nitrate vegetables in boiling water for one to three minutes and discard the cooking water before consumption.
  • Infant foods such as vegetable puree and vegetable congee should be prepared for immediate use.
  • Store the fresh leafy vegetables in a refrigerator if they are not cooked immediately.
How accurate are Greentest's results?

Greentest is highly accurate with less than 10% margin of error. As proved by proficiency tests held in metrology institution laboratories within China, Hong Kong and Taiwan.

Why does a second measurement of the same product provide different results? Sometimes I have 200mg/kg or more difference.

This variation is explained by the fact that the fruit or vegetable being tested has an irregular distribution of accumulated impurities in different parts of the product. For example, closer to the stems of the content of impurities may be much higher.

In addition, for better accuracy testing should not be conducted twice in the same place, because after the first test, the electric conductivity may change the distribution and composition of nitrates in the location tested. The same happens if you conduct a test of water hardness in the same glass of water twice. In this case, we recommend you use different glasses with the same water.

Please remember, to get more accurate results, you need to carefully follow the guidelines within the user manual and instruction on “How to test”.

Does the temperature of food influence the measurements?

The products should be measured when they are at room temperature (at least one hour after storage in a refrigerator), as the temperature of the product will highly influence electric conductivity. The device measures electric conductivity but is calibrated to show the amount of nitrates as there is a direct dependence attached to each type of product. All calibrations are based on products at room temperature only.

Can I use Greentest to detect nitrate content in cooked vegetables?

No. As Greentest was calibrated to detect nitrate ions only in fresh fruit and vegetables

What influences the results of Greentest measurements?

The results of measurements, depends on salt concentration in the intercellular space, conductivity and the condition of the cell membranes of the tested tissue of a product.

Calibrations and updates?

The device is calibrated every time it is switched on. While switching on the device, ensure that the probe is not inserted into the test product. This enhances the measurement precision. Greentest cannot be updated via the internet or any other source. The updated version that will include an expanded list of tested products and other features can be acquired only by purchasing a newer model of the device with an updated version of the software.

Can I change the battery?

The battery cannot be changed, as the device cannot be opened. It can be charged with a micro USB cable. The battery is designed to last 1000 recharges and discharges. One charge will last for 6 hours of continuous use and 3 months for normal household usage. The device has a lifespan of approximately 5 years when used appropriately.

How to clean the device and reduce the risk of bacteria emerging?

Clean the probe with a dry cloth before measuring a product and with a wet cloth after each use (before switching off the device).


Can I add more types of fruits and vegetables?

You cannot do it personally, the device database of fruit and vegetables can only be upgraded by the manufacturer. Greentest cannot be updated via the internet or any other source. The updated version that will include an expanded list of tested products and other features can be acquired only by purchasing a newer model of the device with an updated version of the software.  If you have any products you wish to be inserted in the next version of the device, you are free to let us know and we will take it into account.

Why doesn't the device switch off automatically?

The device does not switch off automatically because it may be measuring a cumulative dose. When you press the STOP button on cumulative dose the device will switch off automatically after a couple of minutes. The timing for the auto switch-off feature can be set up in the device settings.

What is the difference between 1 probe and 2 probes devices?

2 probe devices are designed to offer better accuracy for testing water. When testing water, it is very important to ensure that both probes are parallel to each other when immersing them into a body of standing water for the duration of the measuring process.


What should I do to reduce the level of contaminants?
We suggest several measures to decrease the concentration of additives: try to eat more seasonal cultures; wash greens, fruits and vegetables thoroughly in running water; cut off all the spoiled parts; cut the peeled fruits in half and soak in cold, slightly salted water for 30-40 min (this substantially lowers the level of nitrates in products you had already tested); boil vegetables in large volumes of water and don’t use this water for meals (this procedure contributes to withdrawal of nitrates); don’t cook salad in aluminum dishes; cut off the skin, the stalk, the root, or the kernel (depending on the plant) after detecting higher levels of nitrates.
But remember, the more you cook fresh vegetables the less they will have minerals, vitamins, microelements that are so valuable to our health.
Do nitrate and nitrite pose any special risks for babies and infants?
In 2010 the European Food Safety Authority (EFSA) assessed the possible health risk for children through nitrate in leafy vegetables. According to this, the nitrate levels in the vegetable varieties mentioned do not pose a health risk to most children. Babies and infants aged 1 to 3 years who eat a lot of spinach with a high nitrate content in the course of one day can sometimes reach an intake level at which an increased risk of methemoglobinemia (“blue disease” = cyanosis) cannot be excluded.
Babies in particular show a sensitive reaction to nitrite during the first months of their lives because it alters the red blood cells (hemoglobin). Because of this change, they cannot absorb any oxygen which disrupts the transport of oxygen and can lead to an oxygen shortage (methemoglobinemia). Consequently, a health risk through an increased nitrite intake brought about by the consumption of foods containing nitrate and nitrite is conceivable for babies during the first months of their lives. In practice, however, they hardly consume any food contaminated with nitrite or nitrate during this period.
According to the EFSA report, children suffering from bacterial gastro-intestinal infections should not be given spinach because this can result in a higher conversion rate of nitrate into nitrite, thus increasing the risk of methemoglobinemia.
What quantities of nitrate can be ingested without any health considerations?

The WHO has derived an acceptable daily intake (ADI) for nitrate of 3.7 mg/kg body weight, but this does not apply to infants aged less than 3 months. This value equates to a nitrate quantity of 222 mg/day for an adult weighing 60 kg. A maximum intake of 93 mg/day (25 kg body weight) applies for children aged 3 years and over.

Signs of acute nitrate poisoning

Severe cyanosis of the skin and mucous membranes (can be pallor); Sudden weakness, drowsiness, agitation. Dizziness, severe headaches, blackouts. Shortness of breath. Incoordination. Lower blood pressure, increased heart rate. In severe cases, convulsions, loss of consciousness, coma.

Is there a health risk through nitrate and nitrite in foods?
Blue baby syndrome
Humans are subject to nitrate toxicity, with infants being especially vulnerable to methemoglobinemia due to nitrate metabolizing triglycerides present at higher concentrations than at other stages of development. Methemoglobinemia in infants is known as blue baby syndrome.
Diabetes, Alzheimer, Parkinson’s
According to a new study by scientists at Rhode Island Hospital, millions of Americans could be at risk of serious and even fatal diseases because of chemicals used to fertilizer and to preserve food. Scientists have found a strong link between increasing levels of nitrates and nitrites in our food supply and increasing death rates from Alzheimer’s, diabetes mellitus and Parkinson’s disease.
Nitrates are converted into nitrites and nitrites – into nitrosamines under a number of conditions, and nitrosamines are known to be toxic or carcinogenic.
The presence of nitrate in vegetables, as in water and generally in other foods, is a serious threat to man’s health. Nitrate per se is relatively non-toxic, but approximately 5% of all ingested nitrate is converted in saliva and the gastrointestinal tract to the more toxic nitrite. The only chronic toxic effects of nitrate are those resulting from the nitrite formed by its reduction by bacterial enzymes. Nitrite and N-nitroso compounds, which form when nitrite binds to other substances before or after ingestion (for example, the amines derived from proteins), are toxic and can lead to severe pathologies in humans. Thus, the assessment of the health risk of nitrate to humans should encompass the toxicity of both nitrite and N-nitroso compounds.
Nitrite as such, and nitrate when reduced to nitrite, may react with amines or amides to form carcinogenic N-nitroso compounds (nitrosamines).
However, an intake of vegetables and consumption of drinking water with such a high nitrate content that the ADI is exceeded for a prolonged period should be avoided. Thus, in order to gain as much as possible from the indisputable benefits of vegetables, a reduction in nitrate levels is highly desirable for consumers and probably profitable for farmers.
Do organic grown vegetables have less nitrates than conventional?
No. Though, on average organic vegetables have less nitrates than conventional, some of organically grown products can also have very high amount of nitrate ions. Organic products may be cultivated with a usage of organic fertilizers, which farmers also can use in a very high amount. In addition, the nitrate concentration in vegetables depends on a number of factors including species variation, season, light, temperature, method of growth, and fertilizer used. The nitrate and nitrite levels of vegetables after harvesting can be affected by the storage and processing methods.
That’s why we suggest always to check all veggies and fruits we eat whether they have label of eco/green/organic or not.
Which factors influence the nitrate content in foods?
In addition to the nitrate content of the soil, genetic, geographic and climatic factors also have an influence on the nitrate concentration in the plant: high temperatures result in lower and sustained drought in higher nitrate accumulation. As a rule, higher levels are also to be found in products from northern latitudes of Europe than in those from southern regions. Irrespective of this, levels in greenhouse vegetables normally exceed those of free-range plants. Since climatic conditions and horticultural methods have a major influence on nitrate in certain vegetables, different maximum levels are fixed depending on the season (harvest in winter/summer) and type of cultivation (grown in the open air or grown under cover).
Nitrate plays an important role in the nutrition and function of plants. Nitrate is mainly to be found in cell vacuoles and is transported in the xylem. The xylem carries water and nutrients from the roots to the leaves, while the phloem carries the products of photosynthesis from the leaves to the growth points of the plant (i.e. storage organs such as seeds or tubers). This means leaf crops such as cabbage, lettuce and spinach have fairly large nitrate concentrations whereas storage organs such as potato, carrot, and pea and beans have relatively small concentrations.
Applying nitrogen fertilizer increases nitrate concentrations in the xylem but has virtually no effect on concentrations in the phloem, and therefore leaf crops such as lettuce or cabbage show an increased concentration of nitrate in response to nitrogen fertilizer, except in their very youngest leaves, while storage organs such as peas and beans that are fed by the phloem tend to show little effect.
I bought the veggie 3 days ago, is it ok to eat it?

It’s better to use Greentest to check it. Because the longer fruits/veggies are kept the more nitrates they will accumulate, because of the decay.

What are the sources of nitrates/nitrites?
Because plants cover their nitrogen requirements through nitrate, plant-based foods – especially various vegetable varieties – can contain high nitrate levels. As a basic principle, the nitrate accumulation in the plant depends on the amounts of nitrogen contained in the soil. Storage capacities vary depending on the type and part of the plant.
Vegetables such as rocket and other leaf lettuces, spinach, kohlrabi, beetroot, as well as red and white radish store a lot of nitrate. As nitrate accumulates particularly in the segments of the plant that conduct water, it is to be found in higher concentrations in the stem, leaf veins and outer green leaves.
What is nitrite?

Nitrite is an interim product in the supply of the plant with nitrogen. As plants cover their nitrogen requirements through nitrate, plant-based foods – especially various vegetable varieties – can contain comparatively high quantities of nitrate. In vegetables containing nitrate, microbiological or enzymatic effects can cause conversion of the nitrate into nitrite. This can happen as a result of improper storage, incorrect transport and/or non-observance of the standard rules of hygiene.

What is nitrate?

Nitrates are nitrogen compounds which occur naturally in soil, but which can also be spread through fertilization. Plants utilize the nitrogen contained in nitrates for their own metabolism and to produce protein. Nitrate is extracted from the soil by the roots and distributed throughout the plant where it is converted into high-energy protein compounds by means of photosynthesis. Excess quantities of nitrate are stored, with food plants having different nitrate storage capacities. Nitrate from soil can also be washed into groundwater through rainfall, which means that it can ultimately be found in drinking water too. The nitrate levels in ground and drinking water can be considerable, depending on the predominant form of land use.

Do you have any more questions?

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