Warsaw University of Life Sciences (SGGW) is developing natural food preservation techniques
Technologies that will enable the reduction of artificial preservatives in the future are being developed at SGGW. Scientists use natural products – metabolites including lactic acid bacteria and acetic acid
Dr hab. Dorota Zielińska, prof. SGGW, and dr inż. Katarzyna Neffe-Skocińska, Department of Food Gastronomy and Food Hygiene, SGGW, are developing new methods of preserving food products. The researchers plan to promote technologies that will reduce currently used unhealthy preservatives and replace them with natural products.
Fermentation in the Food Industry
Fermentation is a well-known natural process that has been used by humanity for thousands of years. It is a process by which organic compounds are transformed from one form to another, carried out by enzymes produced by various types of bacteria. The process is still used to produce alcohol, dairy products, cheese, yogurt, and kefir. One of its main benefits is to prolong the shelf life of the given product. This is the subject of intensive research by the SGGW scientists.
Food Processing Bacteria exhibit significant variations. Some of them grow best in low temperatures, while others produce bacteriocins that can kill other microbes, e.g. Salmonella and L. monocytogenes. Some of these factors play a crucial role in protecting from food spoilage. We are interested in those bacteria strains, which may be beneficial and may be used as natural preservatives, said Prof. Zielińska.
Our research is based solely on lactic acid bacteria and acetic acid bacteria strains recognized as safe and approved for use by the European Food Safety Authority, and on the QPS (Qualified Presumption of Safety) list. Nevertheless, when creating new products for food biopreservation, we try to use the new approved bacteria strains. To achieve that, we isolate them from traditional Polish food. We apply the principle of geographic affiliation in this regard, stating that it is better to use microbiota from the same area, added dr inż. Katarzyna Neffe-Skocińska.
The SGGW research team carefully selects bacterial strains from regional food, seeking antibiotic-resistant bacteria strains. The team wants to find a solution to prevent the human organism from increased antibiotic susceptibility when new bacterial strains are introduced. That could potentially occur during the exchange of genetic material between strains.
Food Production Challenges
The food industry is currently facing a series of challenges related to food safety and preservation, as market trends are evolving. Products that contain preservatives may have some impact on human health. But there are some other issues as well. People consume too much salt and sugar. More aware consumers seek products that do not contain preservatives or other chemical additives. Products containing the least E number additives are becoming more and more popular. It is worth noting that the European Commission has established revised guidelines governing the usage of nitrites and nitrates as food additives setting stricter limits for their use. The same applies to the use of salt. Therefore, food producers are seeking solutions that will ensure food safety while also meeting consumer requirements.
Currently, during commercial food production, only a few sources of lactic acid and acetic bacteria are used regardless of the area. As a result, the mass-consumed products do not support the biodiversity in the microbiome of the digestive system. Hence, the natural products such as the starter cultures may be used.
According to the SGGW researchers, one of the beneficial options for the food industry is the use of metabolites produced by lactic acid bacteria and acetic acid bacteria, especially those that exhibit antimicrobial properties, particularly those isolated from traditional Polish food.
Bio-preservation in food mass production does not require adding beneficial bacteria. It is enough to use the compounds referred to as the Postbiotics, i.e., metabolites generated by the microbiota. Postbiotics include peptides, organic acids, and bacteriocins. Such a solution does not begin fermentation processes, but it helps achieve the intended effect by preventing the development of food spoilage microorganisms. This is a common technique of meat and cheese preservation, which are some of the major sources of microbiological contamination, added Prof. Zielińska.
How to preserve food flavor and aroma
According to the scientists from SGGW, the use of bio-preservatives derived from lactic acid and acetic acid bacteria offers broad possibilities not only in protecting food from spoilage but also in broader applications within food microbiology. It is possible to preserve food without changing its properties, as typically occurs in fermentation processes without modifying flavor and aroma. The study effects depend on the composition and proportions of metabolites and the combination of bacterial strains.
The extended shelf life
The SGGW researchers’ studies cover Polish and international bacteria. They import strains from various regions to combine them and achieve maximum health-promoting effects through synergy. Having selected some strains, the team develops bacterial vaccines (so-called starter cultures), which are then tested and undergo further research. The team patents the strains’ compositions and plans to introduce them into food production. Now it is possible to use the probiotic starter culture for the production of dry fermented pork loins and sausages under industrial conditions. The safe and good quality loins and sausages are ready to eat.
The vaccine produced from the SCOBY, also called the tea mushroom is another example. It is used for Kombucha, the drink produced by fermentation of tea. Kombucha has strong antioxidant properties; kombucha has been proven to be an efficient source of antioxidants, along with the capacity for improving the immune system and preventing some diseases, including anticancer abilities. It contains bioactive compounds including organic acids such as glucuronic acid, acetic acid, and gluconic acid. The second actively participates in liver detoxification, supporting the treatment of joint inflammation. Moreover, the acetic acid bacteria present in Kombucha are responsible for the vitamin C biosynthesis, explains Dr Neffe-Skocińska.
The SGGW research team conducted in vitro studies on a potential risk for the development of gastric and colorectal cancers. The experiments show that the effect of the metabolites of the new acetic acid bacterial strains is cytotoxic to gastric adenocarcinoma. According to the researchers, it’s good to look for natural bio-preservatives. At the same time, combining this search with broader clinical studies is a positive approach. However, considerable funding is needed in this regard.
Market plans
SGGW researchers hope that SCOBY’s proprietary composition for Kombucha production will quickly find buyers among beverage manufacturers. Kombucha is popular in Far Eastern countries, as well as in Canada. Perhaps it will also fill its market niche in Poland and attract enthusiasts among those interested in healthy food. The SGGW team emphasizes that on the one hand, there is a significant readiness to implement new technologies for industrial-scale production. On the other hand, it would be very beneficial to conduct further research and development with the involvement of entities originating from the food production sector.
Currently, we have tested different variants of the synergy of multiple lactic and acetic fermentation bacteria strains. Interestingly, several hundred bacteriocins have been identified so far, and today only two of them are used in the food industry. We have tested solutions on industrial and semi-industrial scales. The great advantage of our solutions is that the bacterial metabolites we extract from the culture do not require special purification procedures. It is very promising for industrial scale and the production cost, says Dr Maciej Paszewski, Head of the Center for Innovation and Technology Transfer, SGGW.
To support commercialization and technology transfer, a spin-off company has been established at SGGW to be responsible for implementing new solutions on the market. Unistart is the first spin-off company established at SGGW. Its great advantage is access to existing research experience and the fact that some of the solutions have already been tested and scaled for industrial production. The combination of these experiences means that the company can today not only design new solutions in the field of food microbiology, but also provide various types of specialized services, including extensive analysis for food producers, added Dr Paszewski.