Solutions for microbial control in beverage production

The demand for Ready-To-Drink (RTD) beverages continues at a tremendous rate. There’s a diverse range of products both alcoholic and non-alcoholic, carbonated and still, that appeal to consumers of all ages for all kinds of occasions, from refreshment, hydration, energy, and nutrition to relaxation, on-the-go and social.

We know beverage manufacturers go to great lengths to ensure each RTD is protected against microbial spoilage, especially as these drinks can be rich in sources of nutrition for microorganisms. Protective barriers such as pH, acidity, ethanol, sugar content, level of chemical preservatives (benzoic and sorbic acids), and carbonation all play their part to guard against microbial spoilage, but they can also contribute to the spoilage, if levels are not sufficient to deter. The challenge is particularly acute in low acid, non-alcohol and noncarbonated RTDs.

AEB NEXT is where we develop process biotechnologies and sustainable, easy-to-use solutions for RTD beverage production. These include solutions such as antimicrobials (for example, chitosan, fumaric acid, tannins), antioxidants (anthocyanins, catechins), acidification agents (citric or phosphoric acid) and microbial filtration (as a form of cold sterilisation to avoid thermal processing such as pasteurisation) for microbial control in RTD production.

RTDs are susceptible to spoilage by a range of microorganisms. These are grouped as yeast, bacteria, and moulds. Each give visual defects such as haze, clouds, particulates, and discoloration, as well as flavour changes; all of which impact product quality and shelf-life.

Sources of contamination begin with the raw materials and the production process. Fruits for a range of fruit-based RTDs, including grapes for winemaking and apples for cider production, grains for brewing, natural sugars as sweeteners, all come from non-sterile environments – the natural world. The process equipment, level of cleanliness and handling, packaging and storage conditions can all be optimised to minimise and eliminate microbial contamination.

We understand the added challenges you could face when it comes to microbial control in RTD beverage production, especially if you’re considering a low-acid, low to no alcohol, shelf stable RTD.

That’s why our team in AEB NEXT are ready to help.

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Spoilage microorganisms

YEASTS

Yeasts are primary spoilage organisms since they can grow at acidic pH and under anaerobicconditions. Zygosaccharomyces bailii and Brettanomyces/Dekkera can tolerate high carbonation and moderate concentrations of preservatives. Other culprits are Saccharomyces, Hanseniaspora, Hansenula, Candida and Pichia. Yeast related spoilage can result in production of carbon dioxide in a packaged beverage resulting in the bottle or can bursting.

BACTERIA

In low pH most bacteria will die off; however, certain lactic acid bacteria (Lactobacillus spp. and Leuconostoc mesenteroides) can grow under these conditions, especially when there are sufficient nutrients coming from the fruit in the drink. These bacteria are also resistant to benzoic and sorbic acids. Bacteria found in non-alcoholic beverages include Acetobacter and Alicyclobacillus.
Bacterial spoilage is recognised by haze, sediment, off-flavour formation, and production of gas. Some Lactobacillus and Leuconostoc spp. can produce dextrans resulting in a ropiness appearance in the beverage.

MOULDS

Common beverage spoilage moulds include Aspergillus, Penicillium, Mucor, Fusarium, Byssochlamys, Rhizopus, and Cladosporium. They grow only when dissolved oxygen is present, which is the case for non-carbonated soft drinks. Moulds tend to grow slowly in packaged beverages appearing as soft white clouds floating suspended in the liquid; with the slow growth mould spoilage is often not detected until the product is in the marketplace. Due to the lack of oxygen the mould does not produce spores (fruiting bodies). Mould spoilage is frequently traced to environmental contamination or poorly sanitised equipment.