# Nutritional and Medicinal Properties of Microbial Oil
## 7 Applications of Microbial Oil in the Food Industry and Nutrition  
In today's market, the use of omega-3, particularly in formulations such as infant food, has experienced significant growth, due to its inclusion of DHA. Hence, a growing importance is placed on the production of DHA-rich PUFAs for the safe use of formulas, especially those produced for infants. The production of microbial oils is sustainable and replicable, due to their high yield and low nutrient requirements. Various microorganisms, such as yeasts and algae, are used in microbial oil production. The most common ones are the algae _Ulkenia_ sp. and _Schizodotrium_ sp. ; the mold _M. alpina_; and the yeast _Y. lipolytica_, which has a very high oil production efficiency. Research on lipid production from microorganisms has been ongoing since the 19 th century. However, lipid production by microorganisms for the food industry began in the mid-1970s. Today, microbial oils, which are considered novel foods, are widely used in many different food products. Microbial oils were first used in infant formulas. For example, microbial oils produced by _Schizodotrium_ sp. are used in breakfast cereals and dairy products other than milk-based beverages. Microbial oils produced by _Ulkenia_ sp. are used in various food products, such as bakery products, cereal bars, and soft drinks [106]. The studies conducted from the past to the present have shown that microorganisms can accumulate lipids over 20% of their dry weight. Therefore, lipid production from single-celled organisms began as an alternative for the food industry. The diversity of microorganisms and their ability to accumulate lipids in high amounts make microbial oil production a significantly advantageous method [26]. In the assessment of food safety, one of the key factors is tolerability. Tolerability can be defined as the absence of adverse events or increased sensitivity when consuming a food product. Generally, the following three processes are considered in food safety evaluation: risk assessment, risk management and regulation, and risk communication [107]. Organizations like the FDA and EFSA play significant roles in examining and regulating food components. For instance, in the United States, the FDA handles various tasks related to the assessment of new foods and their components. This may involve submitting a petition to the FDA or making a GRAS determination for a formal pre-market review [108]. Microbial oils' safety has been evaluated and discussed over the last decade, with products like DHASCO and ARASCO having their safety determined through both clinical and nonclinical studies. These oils have subsequently been commercially marketed for use in over 75 infant formulas [109]. The evaluation of the safety of food components relies on an assumption of their potential to cause harm. In this regard, the FDA's RedBook serves as a crucial resource for food safety assessment. In the United States, the FDA follows two paths for determining food safety, as follows: the food additive petition process, where the responsibility lies with the FDA to assess and approve the safety; and the GRAS process, where the responsibility lies with the manufacturer. Many new foods, including SCOs, often follow the GRAS  
The safety of single-cell oils (SCO) is assessed by examining the safety of their components. SCOs typically consist of fatty acids esterified with glycerol and may contain small amounts of other lipid classes. The fatty acids in commercialized SCOs are found in normal human diets or the metabolites of fatty acids. The sterols in SCOs are found in traditional food sources like animal fat, vegetable oil, and human milk. The history of the safe use of individual fatty acids and sterols is further enhanced by their abundance in foods; their small consumption amounts; the extensive information on their absorption, distribution, metabolism, and excretion in mammalian species; and the published safety information on specific compounds [108].