Hungarian 
Consumers are now looking to other beverages, such as plant milks, to replace cow's milk in their quest for a varied diet, as well as for environmental or health reasons such as allergies or intolerances. Plant milks can also form part of a vegetarian diet. Their consumption is growing in popularity. For example, the sector is estimated to grow by 43% by 2021 in the UK. Although they may contain valuable ingredients, they are not considered a complete food compared to milk. While milk is a complete source of protein (i.e., all essential amino acids are present in milk and in the right proportions), plant milk is not a complete source of protein. There are various risks associated with the consumption of these products and care should be taken.
The popularity of home-made plant-based drinks is growing as well: both for economic reasons and because of greater confidence in home-sourced ingredients.
While commercially available products must comply with various standards, this does not apply to drinks made at home. This can pose both nutritional (unbalanced nutrient intake) and food safety problems (hazardous ingredients). In particular, there may be an increased risk for young children whose immune systems are not yet fully developed.
Health risks associated with the consumption of plant milks
Cow's milk is a rich source of proteins, calcium, iodine and B vitamins that plant milks cannot adequately provide. Although plant milks can be fortified with these valuable ingredients by manufacturers, the extent of fortification varies from manufacturer to manufacturer and the final product is usually not as rich as cow's milk in terms of proportions.
The following should be considered when drinking plant milks.
- Sugar is often added to plant milks to enhance the flavour (but unsweetened versions are usually also available).
- Cow's milk contains calcium (an important nutrient for bone health and the prevention of osteoporosis), plant milks are usually fortified with it. For this reason, to ensure adequate calcium intake, it is advisable to choose versions containing at least 120 mg/100 ml calcium.
- While animal products contain vitamin B12 (which is necessary for a healthy brain and immune system), if you are on a vegetarian diet, you should choose milk that is fortified with vitamin B12.
- Commercially available plant milks may contain additives (e.g. carrageenan, plant gums) which, although approved and controlled substances, are not needed by the body.
As they are not complete foods, milk substitutes are not suitable for long-term feeding of infants.
Risks associated with the consumption of nut and seed milks
Products made from different nuts and seeds (e.g. almonds, cashews, macadamias, etc.) may pose a risk of mycotoxins. Mycotoxins can be produced as secondary metabolites of various moulds on a variety of crops such as cereals, dried fruits, nuts, spices and can have long-term adverse effects on human health. The growth and toxin production of fungi can be influenced by several factors, but mainly by temperature and humidity. If the crop is contaminated, the mycotoxin may also be present in the product made from it. The reduction of mycotoxins by consumer action is less feasible and prevention of contamination is more important. The food safety authority continuously monitors products at risk for mycotoxin content to ensure that the risk to the consumer is as low as possible.
Specific risks of rice milk consumption
In addition to the benefits of rice milk consumption, it can also pose various nutritional and food safety risks.
Nutritional risks
- Due to its high sugar content, regular consumption of rice milk can lead to obesity.
- Regular consumption of rice milk as a substitute for cow's milk can lead to calcium deficiency and a lack of other minerals and vitamins important for bone development, and therefore to osteoporosis.
- The protein content of rice milk is much lower than that of cow's milk or soya milk, and it is not complete.
- Like other plant milks, rice milk contains additives to improve consistency and shelf life.
Risk of intake of arsenic and other heavy metals
When rice milk is consumed, the risk of arsenic intake deserves special attention, as rice milk, like rice grains, may contain inorganic arsenic.
Arsenic is a naturally occurring element in many forms. From a human health perspective, two broad groups, inorganic and organic arsenic, are relevant. Inorganic forms are the primary toxic forms, but organic forms of arsenic can also be toxic.
Long-term intake of inorganic arsenic can lead to chronic arsenic poisoning. Depending on the level of exposure, the first effects may not appear for years and may include skin damage, peripheral neuropathy, gastrointestinal symptoms, diabetes, kidney effects, cardiovascular diseases and cancer. The International Agency for Research on Cancer (IARC) has classified arsenic and its inorganic forms as a human carcinogen (Group 1), based on convincing evidence.
The ability of different plants to absorb and accumulate arsenic varies considerably. Compared to other cereals such as wheat and barley, rice has much higher arsenic levels. The high arsenic content is because rice is grown in waterlogged conditions, which favours arsenic uptake.
Brown rice usually contains more arsenic than white (milled) rice, due to the husk. The arsenic content can also be reduced by home cooking. During cooking, the arsenic is removed from the rice grain and released into the rice cooking water. When rice is "cooked dry" or rice cookers are used, the arsenic is reabsorbed into the rice. When using excess water, the arsenic remains in the cooking water. For example, one study found that using five times the amount of water left 43% of the arsenic in the rice during cooking. Soaking rice the night before cooking left only 18% of the arsenic in the rice.
The arsenic content of cooked rice can therefore be reduced by pre-soaking the rice, pouring off the soaking water, boiling it in five times the amount of water and finally removing the cooking water.
Due to the potentially high arsenic content, excessive consumption of rice milk is not recommended. When making rice milk at home, it is recommended that the above recommendations are followed to reduce the risk (see later on making milk at home).
Some food safety organisations (e.g. FSA in the UK) do not recommend the use of rice milk as a substitute for breast milk, formula or cow's milk for children under 5 years of age, both for nutritional reasons and because of the excessive intake of arsenic.
In addition to arsenic, other heavy metals can be found in rice, for example, a recent US study on the contamination of baby food found lead, mercury and cadmium in most of the rice-based snacks and rice puddings tested, in addition to arsenic.
Microbiological risks
When making rice milk at home, there is also a risk of Bacillus cereus toxin poisoning due to inadequate heating and reheating of rice.
This is because raw rice may contain spores of the food poisoning bacterium Bacillus cereus. The spores can survive cooking rice. If cooked rice is stored at room temperature for a prolonged period, the spores can develop into the bacteria, which can produce toxin. The production of bacteria or toxin may increase with storage time at room temperature.
Risks of making plant milk at home
Various recipes are available for making rice milk at home. Some of these involve soaking cooked rice, then blending and filtering the product. However, recipes that involve soaking, milling and filtering the raw rice to produce the drink may pose food safety risks. By omitting the heating step, the microbiological status of the rice is compromised.
The process of pouring boiling water over the raw rice and then milling it after soaking also involves only a short period of heat treatment, which is questionable from a food safety point of view.
The technological difficulties can be overcome by using dedicated plant milk cooking equipment. These usually include grinding and heat treatment, but some versions are also suitable for fermenting the raw plant material.
However, even these devices cannot eliminate potential arsenic, heavy metal and mycotoxin intake and imbalanced nutrient intake, so the excessive consumption of plant milks is not recommended.
References
https://www.jamieoliver.com/features/pros-cons-plant-based-drinks/
https://en.wikipedia.org/wiki/Rice_milk
https://www.nhs.uk/common-health-questions/food-and-diet/can-reheating-rice-cause-food-poisoning/
https://www.who.int/news-room/fact-sheets/detail/mycotoxins
Recommendations
https://www.food.gov.uk/print/pdf/node/282
https://www.food.gov.uk/safety-hygiene/arsenic-in-rice
http://www.foodstandards.gov.au/consumer/nutrition/milkaltern/Pages/default.aspx
Advantages and disadvantages of plant milks
https://www.healthline.com/nutrition/best-milk-substitutes
https://www.healthline.com/health/milk-almond-cow-soy-rice
https://www.medicalnewstoday.com/articles/318612.php
https://www.healthline.com/nutrition/almond-milk-health-benefits
https://www.bbcgoodfood.com/howto/guide/health-benefits-almond-milk