Sucuk is a dry-fermented sausage produced by traditional and industrial methods. Traditional production generally takes place in small businesses without starter cultures, and the sausages ripen under natural conditions. Industrial production uses starter cultures for controlled fermentation and climate-controlled chambers that regulate temperature, airflow and relative humidity during fermentation and drying.
This product, produced using the main process steps of fermentation and drying, is called “fermented sucuk,” according to the Turkish Food Codex Meat and Meat Products Communiqué that came into force in 2012.
Fermented sucuk is defined as a fermented meat product without heat treatment, with a cross-sectional surface having a mosaic appearance, where the moisture content is reduced to 40% or less by chopping bovine and ovine meat and fat, mixing it with flavorings, filling it in natural and artificial casings, applying drying and fermentation processes under certain conditions.
In the same communiqué, the semi-dry fermented sausage type produced by applying the main process steps of fermentation, heat treatment and drying is called “heat-treated sucuk.”
After a short-term fermentation step in heat-treated sucuk, a heat treatment process is applied so that the core temperature is at least 68°C (at least 72°C for poultry meat).
Since heat treatment application facilitates the supply of reliable products, producing heat-treated products is preferred in the industry. However, starter cultures are also needed for controlled fermentation to produce heat-treated sausage. (For more detailed information about starter cultures, see Starter Cultures; Definition, Types and Characteristics)
In addition to the acid formation rate and degree of lactic acid bacterial strains used as starter cultures, their ability to produce bacteriocins or bacteriocin-like metabolites also plays an important role. (For more detailed information about lactic acid bacteria, see Lactic Acid Bacteria; Definition, Classification and Characteristics)
Because fermented sucuk undergoes no heat treatment, selecting the lactic acid bacterial strains is even more important than in heat-treated sucuk. Their rate and extent of acid production are crucial to product safety. Antagonistic activity against foodborne pathogens provides an additional protective effect. The strains also play an important role in developing sensory properties, particularly flavor and aroma.
Starter cultures are also important for producing a consistent product. In many countries, strains isolated and identified from traditional foods have been developed into starter cultures, and research in this area continues.
Lactic acid bacteria, catalase-positive cocci, molds such as Penicillium nalgiovense, and yeasts are commonly used as starter microorganisms in the meat industry.
While Lactobacillus and Pediococcus genus lactic acid bacteria and catalase-positive cocci are preferred as starter cultures in dry fermented sausages such as fermented sausages (salami, Rohwurst, Chorizo, etc.) in Europe, only Lactobacillus and Pediococcus genus lactic acid bacteria are preferred in the USA.
Fermented sausages are characterized by the decrease in pH and the distinctive aroma that develop during lactic acid fermentation.
Lactic acid bacteria, found spontaneously or as a starter culture in fermented meat products, create acid and contribute to both the drying of the product and the inhibition of pathogenic and spoilage microorganisms.
Selected strains suited to different fermented products are now marketed as commercial preparations and widely used in industrial production. Traditional foods are their main source. Many lactic acid bacterial strains have been isolated and identified from sucuk, a traditional fermented meat product.
Lactobacilli, the largest group of lactic acid bacteria with more than fifty species, are widely found in traditional fermented products and industrial starter preparations.
Among lactobacilli used in fermented meat products, Lactobacillus plantarum stands out for its safety characteristics, its ability to adapt to different environments and use a range of sugars, and its probiotic properties.
Lactobacillus plantarum is isolated from fermented sucuks at different rates depending on the fermentation conditions. It is known that Lactobacillus plantarum is the dominant species in fermented sausages at ripening temperatures higher than 25°C, and Lactobacillus sakei and Lactobacillus curvatus are the dominant species at lower temperatures.
For the Lactobacillus plantarum strain to be effective in fermentation, it is essential to determine its technological properties and adapt it to production conditions. Although meat-derived L. plantarum isolates vary between strains, they generally grow at 15°C and 45°C, but cannot grow at 4°C.
It is stated that Lactobacillus plantarum strains can survive in environments containing 6.5-10% NaCl. Lactobacillus plantarum strains that are weak in lipolytic activity are generally capable of hydrolyzing casein, although they show weak proteolytic activity.
In addition, the biogenic amine-forming ability of the lactic acid bacterial strains is an important factor in starter culture selection.
Studies conducted on Lactobacillus plantarum strains isolated from fermented sausages reported that the strains examined did not have decarboxylase activity.
Another feature sought for their use in meat products is the configuration of the lactic acid they produce. Since D(-)-lactic acid cannot be hydrolyzed by lactate dehydrogenase in humans, strains producing L(+)-lactic acid are preferred as starter cultures.
In addition, strains capable of producing acetoin from glucose are reported to cause undesirable aroma in the product.
Lactobacillus plantarum strains can increase product safety when used as starter cultures, as they adapt better to the environment and have a higher probability of preventing possible microbial contamination, thanks to their antagonistic activities and suitable technological properties.
The antagonistic effects of lactic acid bacteria occur through some of the final metabolites they produce, antibiotic-like products, bacteriocins and bacteriocin-like metabolites.
Bacteriocins are proteinaceous bioactive compounds produced by bacteria that exert bactericidal or bacteriostatic effects. Although they act mainly against closely related strains, some are also reported to act against foodborne Gram-negative pathogens.
The first bacteriocin whose use was legally permitted in 1988 was nisin, produced by Lactococcus lactis subsp. lactis.
Today, pediocin PA-1/AcH, produced by a Pediococcus strain, and enterocin AS-48, produced by Enterococcus faecalis, are also used commercially.
After the discovery of nisin, produced by lactic acid bacteria, in the 1920s, many different bacteriocins were identified.
Bacteriocins and bacteriocin-like metabolites have gained importance as potential food preservatives because they generally have high-temperature stability, can maintain their activity at acidic and neutral pH values, and are sensitive to proteolytic enzymes in the digestive system.
Bacteriocins can be added directly to food, or this effect can be achieved by the starter cultures used in foods producing bacteriocins or bacteriocin-like metabolites at a level that prevents the development of spoilage microorganisms.
There are many studies examining meat-derived Lactobacillus plantarum isolates as bacteriocin producers. Studies have reported that using bacteriocin/bacteriocin-like metabolite-producing lactic acid bacteria such as Lactobacillus plantarum as starter or protective cultures will contribute to product safety.
By choosing Lactobacillus plantarum strains originating from traditional products as starter culture or protective culture, significant advantages can be achieved regarding product quality and standardization, aroma and taste formation, and more effective ripening. Their better adaptation to the fermentation environment also supports this.
In addition, using protective/starter cultures with a bacteriocinogenic effect can effectively reduce the measures that can be taken against food pathogens. While the low pH and aw, spices, high salt content, nitrite and competitive flora in fermented sausages create an obstacle against pathogenic microorganisms, disease-causing microorganisms that can survive under these conditions can also be encountered.
In conclusion, starter cultures play an essential role in producing sucuk of consistent quality. Raw materials can vary, particularly in hygienic quality, making appropriate starter cultures important for a standardized, reliable product.
References
Kamiloğlu, A., Kaban, G., & Kaya, M. (2019). Effects of autochthonous Lactobacillus plantarum strains on Listeria monocytogenes in sucuk during ripening. Journal of Food Safety, 39(3), e12618.
Kamiloğlu, A., Kaban, G., & Kaya, M. (2020). Technological properties of autochthonous Lactobacillus plantarum strains isolated from sucuk (Turkish dry-fermented sausage). Brazilian Journal of Microbiology, 51(3), 1279–1287.
Leroy, F., Verluyten, J., & De Vuyst, L. (2006). Functional meat starter cultures for improved sausage fermentation. International Journal of Food Microbiology, 106(3), 270–285.
Heinz, G., & Hautzinger, P. (2007). Meat Processing Technology for Small- to Medium-Scale Producers. FAO Regional Office for Asia and the Pacific, RAP Publication 2007/20.
T.C. Gıda, Tarım ve Hayvancılık Bakanlığı. (2012). Türk Gıda Kodeksi Et ve Et Ürünleri Tebliği (Tebliğ No: 2012/74). Resmî Gazete, 5 Aralık 2012, Sayı 28488; makaledeki tarihsel atıf.
T.C. Tarım ve Orman Bakanlığı. (2019). Türk Gıda Kodeksi Et, Hazırlanmış Et Karışımları ve Et Ürünleri Tebliği (Tebliğ No: 2018/52). Resmî Gazete, 29 Ocak 2019, Sayı 30670.
Aybike Kamiloğlu
Aybike Kamiloglu, Ph.D., is an Associate Professor of Food Engineering at Bayburt University, where she works in the Division of Food Technology within the Faculty of Engineering. She received her B.Sc. in Food Engineering from Hacettepe University in 2007, completed her M.Sc. in Food Engineering at Ankara University in 2011, and earned her Ph.D. in Food Engineering from Atatürk University in 2016. Her formally recognised academic field is Food Sciences and Engineering.
Dr. Kamiloglu has nearly twenty years of education, professional practice, research, and teaching experience in food engineering. Between 2009 and 2010, she worked as a food engineer at the Bayburt Provincial Directorate of Food, Agriculture and Livestock. This professional background complemented her subsequent academic work in food production, food safety, meat technology, microbiology, and food-process engineering.
Her principal research interests include meat science and technology, fermented meat products, food microbiology, lactic acid bacteria, functional starter cultures, bacteriocins, bioactive peptides, gamma-aminobutyric acid production, food-processing operations, drying technologies, extraction optimisation, ultrasound and microwave applications, and the recovery and utilisation of bioactive food components. Her work also encompasses natural ingredients, food texture, physicochemical quality, shelf life, nanoparticle synthesis, and the technological use of microbial cultures.
Her university profile currently lists 27 peer-reviewed research articles, 20 of which were published in SCI-Expanded-indexed journals. Her research has appeared in journals including the Microchemical Journal, Ultrasonics Sonochemistry, the Journal of Food Science, the Journal of Food Process Engineering, the Journal of Food Safety, the Brazilian Journal of Microbiology, Food Science and Technology International, Chemistry & Biodiversity, the Journal of Texture Studies, and Biomass Conversion and Biorefinery. She has also contributed a chapter to an international scientific book.
Dr. Kamiloglu has presented or co-authored 30 national and international conference contributions, including 22 international papers or presentations. Her conference and publication record covers fermented sausages, meat quality, starter cultures, lactic acid bacteria, microbial metabolites, food-processing technologies, bioactive compounds, drying, extraction, food texture, and functional ingredients.
She has participated in five completed scientific and applied research projects, serving as project leader on three and as a researcher on two. These projects have addressed bacteriocin-producing lactic acid bacteria isolated from traditional meat products; the use of tarragon in fermented sausage; the effects of germinated mung-bean flour on beef patties; ultrasound-assisted extraction of phenolic compounds; and the optimisation of gamma-aminobutyric acid production by Lactiplantibacillus plantarum in a meat-protein model system. She has supervised six completed master’s theses concerning pectin extraction, selenium and silver nanoparticle synthesis, exopolysaccharide-producing bacteria, gamma-aminobutyric acid production, plant extracts, and the physicochemical and bioactive changes occurring during black-tea processing.
Her undergraduate and graduate teaching includes Meat Science and Technology, Meat and Meat Products Technology, Meat Products Processing Engineering, General Microbiology, Fundamental Operations in Food Engineering, Functional Starter Cultures, Shelf Life of Foods, Physical Properties of Foods, Technical Drawing, and Computer-Aided Technical Drawing.
Dr. Kamiloglu has served as Vice Chair of the Department of Food Engineering since 2018. She is also a member of the Institute of Food Technologists and serves on the editorial board of the Bayburt University Journal of Science. As an author for Gıda ve Sağlık, she contributes her expertise in meat science, food microbiology, starter cultures, food-processing technologies, and food engineering to the preparation of scientifically grounded and accessible content.