What is Geotrichum candidum?
Geotrichum candidum has gone through taxonomic updates since the genus Geotrichum was first identified in 1809 and even nowadays the genus is still evolving [1]. This acid-tolerant yeast-like fungus used to be characterised as a middleman between molds and yeasts but now it’s recognised as a yeast [2].
G.candidum is the most well-known species of its genus and thrives on nutrient-rich, moist surfaces. It can be found in a variety of environments, including soil, water, air, silage, grass, plants, fruits, vegetables, raw milk, and dairy products. It is also a natural part of the digestive systems of humans and animals, coexisting as a commensal organism [1].
Application of the G. Candidum fungus in the food industry
G.candidum is widely recognized as a safe microorganism with a long history of use in fermented foods. This fungus naturally occurs in raw milk from various animals, including cows, goats, sheep, camels, and buffaloes, although typically in low concentrations.
In dairy production, G. candidum is often added as a supporting culture to create fermented milks like kefir and a variety of ripened cheeses. These include soft mold-ripened cheeses, smear-ripened cheeses (both soft and semi-hard), and acid-coagulated cheeses. By the third day of ripening, G. candidum begins to grow on the cheese surface, playing a key role in shaping its flavor, aroma, and appearance.
The fungus contributes to the cheese’s distinct taste, which can range from mildly cheesy and moldy to fruity and cidery. It also enhances the cheese’s texture and look, giving it a velvety, lightly fluffy, or felted surface [1].
The dangers of G. candidum: Risks and spoilage potential
While the fungus Geotrichum candidum is widely used in food production, it must be handled carefully because it can also cause spoilage in certain dairy products like buttercream and cottage cheese. If not properly controlled, this fungus can lead to defects in cheese, such as slippery rinds or “toad skin” [1]. Beyond dairy, G. candidum is a common culprit in spoiling fresh-cut and processed fruits and vegetables, including canned tomato paste, frozen green beans, citrus fruits, juices, and chopped carrots. Its growth in these products can result in unpleasant flavor changes and reduced quality [3].
In food production machinery, G. candidum poses another challenge. Known as "machinery mold," it can thrive on internal surfaces of processing equipment like ports, valves, or filler heads. It has also been found on surfaces such as fan blades, air vents, and rubber seals in food-processing facilities, highlighting the importance of strict hygiene practices to prevent contamination. These areas are often difficult to disinfect and require disassembly for thorough cleaning [3]. The fungus can form a powdery buildup on stainless steel, rubber, or plastic components, leading to significant economic losses for producers [1].
Prevention and disinfection with sustainable disinfectant
Once again, prevention is fundamental. Regular disinfection of not just process water but also surfaces of the industrial machinery reduces the risks of contamination of the food products. Generally, strong chemical disinfectants, for instance hydrogen peroxide or peracetic acid, are working well but need to be used with caution as they are not necessarily user-friendly. An alternative approach involves the use of hypochlorous acid (HOCl)-based disinfectants.
Hypochlorous acid (HOCl) based disinfectant is effective against a broad range of microorganisms. HOCl is naturally found in the white blood cells of all mammals to fight infections in the body [4]. The Watter System produces Watter disinfection solution that facilitates HOCl as its active substance.The production is in-situ so you are always provided with a fresh disinfectant when you need it. The Watter System requires only water, salt and electricity. Moreover, with the in-situ production you can significantly reduce the need for canisters of disinfectant which reduces CO2 commissions and the plastic usage in your company.
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