In our markets with exceptional growth in the cider and beer-mix product categories, these products pose a great microbiological challenge to the filling processes as they all contain plenty of readily fermentable sugars. The use of DMDC (dimethyldicarbonate) as a sterilant has been showing some very promising results. From the company LANXESS Deutschland GmbH, which markets a DMDC product under the commercial name Velcorin®, we have received this article, based on microbiological tests performed by Weihenstephan Research Center for Brewing and Food Quality, highlighting the advantages of the use of DMDC.
Author: Paul Marquardt
Beer-based beverages and cider have been growing in popularity among consumers for years. The market is seeing dynamic growth, and an endless stream of new flavors can be found on store shelves. In Great Britain, for instance, apart from beer, cider is one of the most popular alcoholic drinks, with 600 million liters being produced in the country annually. Despite all the diversity of the beer-based beverages on the market, the majority of new products still fall into the category of the classic “shandy.” Likewise for cider, it is the classic variations with apple and pear that dominate, even though new flavors, such as strawberry and blueberry, repeatedly come out on the market. For example, 75 percent of new products are pure apple or pear cider.
Of the new mixed beer product launches between 2010 and 2014, 80 percent had a citrus component, 6 percent cola and 4 percent grapefruit, in addition to numerous other products. In total, 20 entirely new beer-based beverages have been introduced in Germany alone since 2010, in addition to over 33 new beverages and flavors resulting from product range expansion.
The cider market is highly dynamic. For instance, in the same period, a total of 38 products were introduced to the German market. Apart from Germany, the figures for England and France are just as remarkable. A total of 94 (48/46) new ciders have appeared on supermarket shelves since 2010 (source: Mintel). It is well-known that these usually sugar-based beverages are susceptible to secondary contamination during the filling process, posing a great challenge for filling plants. Cold sterilization with DMDC proves to be extremely helpful in this application.
DMDC has proven effective for decades as a cold sterilant in the production of non-alcoholic soft drinks, wines and ciders. DMDC is added to a beverage immediately prior to filling and even at low doses proves very effective against the typical microorganisms that spoil beverages.
DMDC has been approved for apple and pear cider since 2010, and for beer-based beverages since 2012. The approvals are based on Regulation (EC) No. 1333/2008, Annex II, and DMDC is already used by customers for the microbiological stabilization of these products.
Beer-based beverages are an important market segment for DMDC products. In order to verify that the DMDC product Velcorin® from LANXESS Deutschland GmbH has no influence on the flavor profile of treated beverages, the Weihenstephan Research Center for Brewing and Food Quality was commissioned to conduct a triangle test according to the MEBAK II2.34.7 standard. Comparing four beverages treated with Velcorin® (and the corresponding, untreated control samples) showed that no statistical difference existed between the samples. In other words, adding Velcorin® did not alter the flavor. Figure 1 shows the results of the triangle test and the types of beer-based beverages that were tested.
Following successful approval, the goal was to generate data in the laboratory on the effectiveness of Velcorin® against typical microorganisms that spoil beer-based beverages. A two-pronged approach was taken:
1. Microbiological testing in the company laboratory
2. A risk study on the microbiological spoiling of beer-based beverages, in collaboration with the Weihenstephan Research Center for Brewing and Food Quality.
As part of this study, selected market samples were inoculated with eight different spoilage microorganisms. The selected microorganisms included the following: Lactobacillus brevis, Pectinatus frisingensis, Saccharomyces cervevisiae, Saccharomyces pastorianus ssp. Carlsbergensis, Saccharomyces cervevisiae var diastaticus, Dekkera anomal, Wickerhamomyces anomalus and Kazachstania exigua.
The targeted inoculation concentration was 300 CFU/ml. One group of samples was treated with 250 mg/l Velcorin®, equivalent to the maximum legally permissible value for this beverage segment. Corresponding blank samples, with no added Velcorin®, were treated in similar fashion.
During subsequent microbiological analysis, the microbial growth of the samples with and without Velcorin® treatment was compared. Figure 2 shows a summary of the results. The Saccharomyces cultured yeasts and the Saccharomyces wild yeast Saccharomyces cerevisiae var. diastaticus are capable of spoiling the beverages with no added Velcorin®. This poses a problem for consumer safety because of the fermentation of the existing sugar, combined with the rising pressure inside the contaminated bottles. No growth was detected in any of the beverages treated with Velcorin®.
This study confirms the results obtained by the company’s own microbiology laboratory. The tests conducted there included some additional microorganisms compared to the study described above. A total of five microorganisms in two beer-based beverages were tested for their growth potential. The targeted inoculation concentration likewise was 300 CFU/ml at a Velcorin® dosage of 250 mg/l. Figure 3 shows a summary of the growth test results.
The results for the two beer-based beverages differ only in the growth of Candida tropicalis. This organism did not grow in the untreated beer-based beverage that contained a proportion of pilsner beer, but did grow in the wheat beer-based beverage with no added Velcorin®. The reason for the greater susceptibility of the mixed wheat beer-based beverage could not be identified, which prompted the Weihenstephan Research Center for Brewing and Food Quality to analyze the chemical parameters of the beer-based beverages. Only a slight connection was observable between the microbiological susceptibility of the tested beverages and their chemical parameters, such as alcohol content, bitterness units, carbonization and pH.
Following approval in 2010, successful studies also were conducted on cider to determine the effectiveness of Velcorin® against typical spoilage microorganisms in this beverage segment. These primarily are Saccharomyces yeasts, although Brettanomyces species, Lactobacillus species and acetic acid bacteria also were isolated from the cider samples. DMDC technology today is used in a variety of applications in the cider industry. Apart from being used for SO2 reduction and for treating turbid ciders that are unsuitable for pasteurization, DMDC also is used as a substitute for persistent preservatives.
The European market for beer-based beverages and cider has seen dynamic growth in recent years. The great variety of products that are susceptible to microbiological spoilage are a major challenge for filling plants. Laboratory tests have shown that DMDC technology can help to solve these problems.
In industrial applications, DMDC is added by specially designed metering devices upstream of the filling machine, in volumes that are proportional to the product flow. The metering equipment can easily be integrated into existing filling systems.
DMDC is used across Europe for the microbiological stabilization of beer-based beverages and ciders. Beverage makers can now use their beer filling lines to also fill more sensitive beer-based beverages, as well as shandies, which previously were made with sugar-free soft drinks, but now can be made with sugared soft drinks thanks to the protection against microbiological spoilage. Combined with suitable, upstream HTST pasteurization, producers can eliminate a tunnel pasteurizer depending on the respective, on-site conditions. Corresponding tests have already been conducted on an industrial scale with successful results.
The commercial DMDC product Velcorin® used in the tests performed by Weihenstephan Research Center for Brewing and Food Quality is manufactured by LANXESS Deutschland GmbH.
LANXESS Deutschland GmbH
Material Protection Products Business Unit
Beverage Technology Business Line
Kennedyplatz 1, 50569 Cologne, Germany
Tel.: +49 (0)221 8885-4460
E-mail : firstname.lastname@example.org