How Microbes Are Essential for Tasty Food

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Microbes in food

By Ally Hughes

Microbes are found everywhere in nature. They play important roles in every facet of our lives, often without us even noticing. From the milk you add to your morning coffee to that well-deserved glass of wine in the evening, microbes are essential in our food industry. Due the sourdough and home brewing crazes of 2020 (#lockdown), many of us have become aware of the role of yeast in the production of bread and alcohol, however microbes have essential applications in the sustainable production of crops and seafood, their proteins are used as meat substitutes, and are involved in flavouring some our favourite after-dinner treats. Let us take you through our menu of exciting applications of microbes in food production, innovation, and taste.

STARTERS – FOOD PRODUCTION

FERTILISERS - Potassium, alongside nitrogen and phosphorous, are the three most important nutrients needed by plants for growth. Despite 2% of the Earth’s crust comprising of potassium, over-working agricultural land has led to a scarcity of potassium in the soil. This is because most potassium (80-90%) is held in ores and is therefore unavailable for plants to use for nutrition. Synthetic fertilisers were initially produced to correct this problem (as has been done for nitrogen and phosphorous depleted lands) however, this has led to an increase in production costs and thus higher costs paid by the consumer. But there is some good news! Scientists have discovered a group of bacteria and fungi known as Potassium Solubilising Microbes (PSMs) that can release potassium from these ores and make it available for uptake by plants. Hydroponic studies (growing plants in water instead of soil) of a variety of plants including tea, wheat, maize, lettuce, and tomatoes, have shown increased uptake of essential nutrients, better growth, and higher yields.

THE MICROBES - Potassium Solubilising Microbes include rhizobacteria (Bacillus, Acidothiobacillus, and Paenibacillus), and fungi, in particular Aspergillus spp.

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AQUACULTURE - Another food industry that has suffered greatly due to an ever-increasing demand, is aquaculture. Fishing in many parts of the world is becoming unsustainable and the oceans’ populations are under serious threat from acidification, pollution, and global warming. For these reasons, seafood producers are turning toward aquaculture, the process of farming fish, molluscs, and other aquatic organisms specifically for food. And, of course, microbes play a huge role in this industry, both positively and negatively. Photosynthetic microbes, such as cyanobacteria and microalgae, are used as feedstocks in aquaculture as they contain a high abundance of protein and so-called healthy fats. In fact, they are so packed with nutrients, that you can now buy dried cyanobacterial/microalgal powder such as Spirulina and Chlorella to add to your smoothies for an extra health boost!

THE MICROBES - Isochrysis, Chaetoceros, Chlorella, and Tetraselmis spp. are some of the more commonly used genera of microalgae used for fish and mollusc farming.

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MAIN COURSE – FOOD INNOVATION

FERMENTATION - As mentioned at the top of the article, our newsfeeds were inundated with pictures of starter cultures and baked sourdough loaves. But bread and beer aren’t the only examples of fermentation in our diet. Historically, fermentation was used to preserve food from spoilage. Vegetables were covered in brine and placed in a sealed container where bacteria converted the sugars in the vegetables into lactic acid. FEMS has an excellent review on the dynamics of microbe populations in fermentation. This not only gives the food the pickled taste that we enjoy, but also prevents harmful bacteria from spoiling the food. Today we have other methods of preserving food, but fermented foods such as sauerkraut and kimchi are still popular for the flavour that is produced during the fermentation. A similar process is used for curing meats such as chorizo, pepperoni, and prosciutto, except the meat is coated in salt and left hanging in a dry place for several days. So why not start your next fermentation adventure today?!

THE MICROBES - There are a number of microbes involved in different fermentations but commonly a combination of Saccharomyces cerevisiae and Lactic Acid Bacteria (LABs) such as Lactobacillus, Streptococcus, and Leuconostoc spp. Meat fermentation often include species of Enterococcus and Kocuria.

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MICROBIAL PROTEINS - One of the most interesting food trends in recent years - from a microbiologist’s perspective anyway – is veganism. It has spurred a wealth of innovation from the food industry and microbes have been incredibly important in the development of meat substitutes. One of the earliest examples of a meat substitute available in supermarkets was Quorn which uses mycoprotein produced by a fungus. In 2009, biochemistry Professor Patrick O’ Brown discovered that heme protein was the main factor in giving meat its, well, meatiness. Heme protein is also produced by some plants and The Impossible Foods team, led by Prof. Brown, were able to genetically engineer yeast to produce the heme protein from plants. Not only does their product, The Impossible Burger, boast to have all the same great flavours as a beef burger, but it’s also much lower in salt and cholesterol. And just last year, researchers at Sustainable Bioproducts discovered a microbe in the hot springs at Yellowstone National Park that contains all 20 amino acids. These microbes offer a healthier and more sustainable way to consume protein.

THE MICROBES - Quorn uses mycoprotein from the fungus Fusarium venenatum. We know the Impossible Burger produces heme using genetically engineered yeast but that is all the detail we have. As for Sustainable Bioproducts, they are keeping their secrets close to their chest so we don’t even know what type of microbe they are working with. 

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DESSERT – CHOCOLATE, COFFEE, AND WHISKEY

TASTE PROFILES - For me, there’s nothing nicer than curling up on the couch with a hot cup of coffee and a bar of my favourite chocolate. And none of these treats would taste as nice if it weren’t for microbes. Although technically, these fall under the banner of fermentation as well, I thought I’d separate the sweet and savoury courses as the reasoning behind the applications differ. Whilst with vegetables and meat, preservation was the main aim (with the added bonus of extra flavour), for coffee and chocolate, the harvested beans are fermented to remove bitterness and breakdown pectin, allowing cacao beans to be converted into the smooth chocolate we know and love. Yeast and bacteria work together to produce the aromatic nutty flavours that chocolate and coffee are famous for. This is the reason that you may pick up on some chocolate or coffee notes when tasting whiskey, it’s the microbes that are producing the flavour!

THE MICROBES - Fermentation of chocolate and coffee often contain a mixture of yeasts (Kloeckera, Candida, and Rhodotorula spp.), lactic acid bacteria, and Acetobacter (Acetic Acid Bacteria, AAB).

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Bon apètit

FEMS Microbiology