Analysis of rice

The rice plant grows mainly in humid and warm climate zones. It requires a lot of water and can be grown both in flooded areas and in drier environments. Rice is mainly grown in rice fields, where the seeds are planted in moist soil or sown in flooded fields. After harvesting, the rice grains are dried, hulled and cleaned to prepare them for human consumption. The largest rice producers are China, India, Indonesia, Bangladesh, Vietnam and Thailand.

Rice comes in different varieties and qualities, which can differ in size, shape, color, aroma and texture. Popular varieties include basmati, jasmine, long-grain and short-grain rice.

Rice thrives mainly in water. The rice plant absorbs water and nutrients through its roots. However, harmful substances such as inorganic arsenic and the heavy metal cadmium also end up in the rice grains. Arsenic and cadmium are natural components of soils and not necessarily the result of environmental pollution. Inorganic arsenic is classified as carcinogenic, too much cadmium can damage the kidneys.

Producers and distributors of rice must ensure its quality and safety. The main substances of concern in rice include

Inorganic arsenic

The amount of inorganic arsenic in rice varies depending on the rice variety, growing region, growing conditions, irrigation methods and processing method. Arsenic mainly accumulates at the edge of the rice grain, i.e. in the husk. Brown rice, also known as brown rice, has a higher arsenic content than white rice, where the outer layers have largely been removed. Basmati tends to have lower arsenic levels than other types of rice.

To reduce the arsenic content in rice, the rice should be washed thoroughly in plenty of water before consumption. In this way, some of the arsenic can pass into the water. It is also advisable to cook the washed rice and drain off any excess cooking water.

Cadmium

Cadmium is a heavy metal that accumulates in the human body and can lead to kidney and bone damage if consumed in large quantities over a long period of time.

The drought in rice-growing regions caused by the climate crisis means that the plants accumulate more of the cadmium contained in the soil in the rice grains. This can vary from field to field, depending on how high the cadmium content in the soil is. Here too, brown rice is more affected than white rice, where the outer surface layer is removed.

Mineral oils

Mineral oil is suspected of being carcinogenic. It can contain various compounds, including saturated hydrocarbons (MOSH) and aromatic hydrocarbons (MOAH), which can alter the genome, especially when consumed in large quantities. The European Food Safety Authority (EFSA) has set guideline values for mineral oil in food and recommends keeping exposure to these compounds as low as possible.

Rice can be exposed to various harmful substances that can occur during cultivation, processing or storage. Agricultural and storage pests can also affect the quality of the rice harvest. These include, for example, the rice weevil. Rice weevils are small, brown beetles that can feed on rice grains. They can appear during storage and cause damage by drilling holes in the grains and making them inedible.

Labeling and label verification, consumer information (GMO)

The labeling inspection for rice refers to the inspection of the labeling on the packaging to ensure that it complies with legal requirements. This includes information such as country of origin, production or processing methods, nutritional information and possible allergens. Labeling must be clear, accurate and complete to provide consumers with accurate information about the product and allow them to make an informed purchasing decision.

The labeling of GMOs (genetically modified organisms) in rice refers to the indication on the packaging whether the rice contains genetically modified ingredients or not. In some countries, there are legal requirements that oblige manufacturers to label genetically modified ingredients on the packaging. The purpose of this labeling is to provide consumers with transparency about the content of the product so that they can make an informed decision. If the rice does not contain any genetically modified ingredients, it will be labeled as "GMO-free" or similar on the packaging.

The use of pesticides in rice cultivation can lead to residues that remain in the rice. Although most pesticides are degraded or removed according to current regulations, residues may be present in some cases and pose potential health risks, especially when consumed in excess.

The formation of mycotoxins depends on various factors, including environmental conditions during harvesting, storage and processing of raw materials. Mycotoxins are toxic metabolites of molds that can grow on rice and other grains, especially when stored in humid conditions. They can develop during the growth, harvest, storage or transportation of food. The most common mycotoxins that can be found in rice include aflatoxins and ochratoxins, which can be harmful to health in high concentrations. Mycotoxins are analyzed using LC-MS/MS, for example.

Rice can absorb heavy metals such as arsenic, cadmium and lead from the soil in which it is grown. These heavy metals can come from natural sources or be released into the environment through human activities such as industrial pollution, mining or the use of fertilizers and pesticides. High concentrations of heavy metals in rice can be harmful to health, especially if it is consumed regularly. In pregnant women, the intake of arsenic could endanger the development of the unborn child.

Atomic absorption spectrometry (AAS), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence analysis (XRF) are frequently used to determine heavy metals. The laboratories of the Tentamus Group rely primarily on ICP-MS.

Mineral oil can occur in rice, especially if the rice comes into contact with mineral oil sources during cultivation, processing, storage or transportation. This can happen in various ways:

• Environmental contamination: air or soil pollution from e.g. industrial activities or transportation
• Processing and storage: machine oil, lubricants or packaging materials can be contaminated with mineral oil residues
• Transportation and storage: Containers, vehicles or packaging may come into contact with mineral oil and contain residues

Mineral oil hydrocarbons (MOH) comprise two main groups: Saturated Mineral Oil Hydrocarbons (MOSH) and Aromatic Mineral Oil Hydrocarbons (MOAH). Gas chromatography (GC), mass spectrometry (MS) and HPLC-GC-FID are common methods for analyzing mineral oils.

Gas chromatography coupled with flame ionization detection (GC-FID):

The sample is extracted, typically with an organic solvent (e.g. hexane) to dissolve the mineral oils. Then the extracted mineral oils are passed through a gas chromatography column where they are separated based on their different physical properties. A flame ionization detector (FID) measures the amount of mineral oils by ionizing the organic compounds contained in the gas stream and determining their concentration.

Gas chromatography coupled with mass spectrometry (GC-MS):

The separated compounds are ionized in a mass spectrometer and analyzed according to their mass-to-charge ratio. The mass spectrometer provides detailed identification and quantification of petroleum hydrocarbons, including MOSH and MOAH.

Chemical analyses are carried out to obtain information on the nutrients, safety and quality of rice, among other things.

Rice is gluten-free and naturally low in fat. It contains no cholesterol, making it a heart-healthy option. Nutrients such as carbohydrates, proteins, fiber, minerals (e.g. iron, magnesium, phosphorus, potassium and zinc) and antioxidants contribute to a healthy diet and various bodily functions.

When sending rice samples to our laboratories, there are a few simple aspects to consider to ensure that the samples arrive in good condition and that the analysis results are reliable. These include the following points:

Packaging

Use airtight and leak-proof containers or bags to prevent crumbs from escaping. Use insulated packaging if necessary.

Transportation conditions

Find out about the specific requirements of the laboratory in terms of temperature, humidity and transportation time. We will be happy to advise you or collect the samples from you.

- Commission Regulation (EC) No. 1881/2006 (Contaminants Regulation)
- Regulation (EC) No 396/2005 of the European Parliament and of the Council (maximum residue levels of pesticides)

The following laboratories from the Tentamus Group offer rice analysis:

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