Prevening Product Spoilage

Spoilage-yeast detection is an important part of the routine controls carried out by bottlers. Testing for the presence of this special class of yeasts is especially important in non-alcoholic drinks. Left undetected, they can damage the quality of a batch, resulting in clouding and off-flavors. Their fermentation can lead to the formation excessive gas, causing cans to distort, split or burst.

In the case of glass containers, such an explosion poses a potential safety threat to consumers. With the proper identification of these yeasts in advance, these spoilage issues can be easily avoided or addressed.

Risk factors
Beverages, particularly functional beverages, are becoming increasingly complex—new products are being created, processes are being modified, and shelf-lives are being extended. While these all serve to meet the consumer demand for new and exciting drinks, the number of resulting product-assurance or quality-control issues has also mushroomed. On one hand, processors need to secure competitive advantage; on the other, they must reevaluate the microbial risks for their product ranges.

Spoilage potential depends on a product’s own unique composition. Values like pH, water activity, and nutrient content are all crucial for stability. In general, only a very limited range of microorganisms can spoil non-alcoholic beverages (both still and carbonated) due to their makeup, and related production processes.

Such spoilage is usually caused by acidophilic or acidotolerant microorganisms (e.g. lactic acid bacteria or Alicyclobacillus), as well as osmophilic and osmotolerant microorganisms (e.g. yeasts) that are capable of multiplying in the beverages.

Fermentative or non-fermentative yeasts?
There are two types: non-fermentative and fermentative. Non-fermentative yeasts are only of secondary importance in their ability to spoil beverages--usually they need oxygen to grown and only have an influence if sealing is improper or the container is broken.

However, fermentative yeasts can wreak havoc, causing the majority of product damage. Fermentative yeasts can be further classified as highly-fermentative spoilage yeasts or opportunistic spoilage yeasts. Highly-fermentative spoilage yeasts quickly cause deterioration—even if present in very low amounts; while opportunistic spoilage yeasts only cause product breakdown if the individual conditions are right.

Overall, fermentative yeasts represent a significant danger because they can tolerate a wide spectrum of pH (from pH 3 to 11) and temperature (0°C to 45°C) ranges. They also have the ability to grow in environments with and without oxygen. Rightly considered survival experts, these yeasts pose a special risk to non-alcoholic drinks. In addition to causing changes in taste and smell, most automatically switch to fermentation in an oxygen-free environment, producing large quantities of alcohol and carbon dioxide (CO2) at varying speeds.

So quality-control personnel need to have a thorough understanding of the two types of fermentative yeasts. The presence of highly-fermentative or opportunistic spoilage yeasts will determine which strategies are used to ensure product quality and safety. Currently, a modern analysis method is needed to reliably distinguish between the two.

Conclusion
The bottom line is this: beverage-spoiling microorganisms are present worldwide and do not discern between different geographical areas. Beverage-spoiling yeasts or bacteria can ruin beer in Vietnam or in Germany. So it is important is that they are quickly identified and pursued. Effective detection tools can close-in on weak spots in raw materials, production processes and hygiene monitoring, in order to assure product stability.

With Vermicon’s detection system VIT-Spoilage Yeasts, it is possible to quickly detect both groups of fermentative yeasts and clearly distinguish them from any non-fermentative yeasts present. If the test result is negative, then there are no fermentative yeasts present in the sample and you can quickly and safely release your products.

If the test result is positive, you can see whether highly fermentative or opportunistic spoilage yeasts are present in the sample. It also enables the detection of spoilage yeasts within 36 hours, as opposed to one week or more. Thus, the products can be released earlier which saves storage costs and increases the availability of the product in the market. In case of contamination of raw materials such a fast result enables the possibility to react before the raw materials are used for production.