In vitro antimicrobial activity of ginseng extract against Staphylococcus aureus, Salmonella Typhimurium and Listeria monocytogenes and its inhibitory effects on these pathogens in cooked ground beef.

Present study is focused on exploring in vitro antimicrobial activity of ginseng extract (GE) against Staphylococcus aureus, Salmonella Typhimurium and Listeria monocytogenes and their biofilm forming ability, then determining its antimicrobial efficiency during the storage (4 and 10 °C) of cooked ground beef contaminated with these pathogens. Results revealed that the minimum inhibitory concentration (MIC) for S. aureus, S. typhimurium and L. monocytogenes were 90, 70 and 40 mg/mL, respectively. GE was also able to inhibit biofilm production by S. aureus and L. monocytogenes, whereas S. typhimurium did not produce biofilm with or without GE application. On the other hand, the results of GE aplication in ground beef indicated that GE incorporation at 0.5% or more reduced S. aureus and S. Typhmurium counts in cooked ground beef at the end of 30 d storage at 4 °C (P < 0.05). Using 1% or more GE totally inhibited S. Typhmurium after 15 d storage at 4 °C (P < 0.05). However, GE application did not affect S. aureus or S. Typhmurium counts in cooked ground beef stored at 10 °C. Furthermore, incorporation of 0.5% or more GE generally inhibited L. monocytogenes growth in cooked ground beef at the end of storage at both 4 and 10 °C (P < 0.05). In general, pH was lower in samples with GE than those without GE regardless of differences in the type of tested pathogen, storage time and temperatures (P < 0.05). Although similar aw was generally obtained on processing day, lower aw was observed in GE containing groups at the end of storage for both storage temperatures (P < 0.05). Oxidation reduction potential (ORP) in all groups generally increased during storage at both storage temperatures (P < 0.05). In conclusion, our results demonstrated that GE has an important role in controlling growth of tested pathogens and may be used as a natural agent by the meat industry to inhibit the growth of food-borne pathogens in cooked processed meat products during storage.

Effects of Aloe vera utilization on physochemical and microbiological properties of Turkish dry fermented sausage.

The study aimed to determine the minimum inhibitory concentration of Aloe vera extracts obtained by different extraction methods on eight strains from five different pathogens (Pseudomonas fluorescens, Listeria monocytogenes, Salmonella spp., Escherichia coli and Staphylococcus aureus) in the first phase and utilize Aloe vera extract in sausage processing in the second phase. Sausages were evaluated for thiobarbituric acid reactive substances (TBARS), physicochemical and microbiological properties. The first phase results indicated that the highest inhibition was determined in Listeria monocyctogenes 472 regardless of tested Aloe vera extract doses and extraction methods (Tukey HSD, P < 0.05). The highest Listeria monocyctogenes 472 levels reached was 0.38 log10 cfu/g. The second phase results revealed that Aloe vera containing treatments of sausage had lower pH than others after storage (ANOVA, P < 0.05). Dry matter, protein, fat and ash contents of sausage dough increased in all treatments after fermentation (ANOVA, P < 0.05). After 30 d storage, 48 and 45% TBARS reductions were obtained in sausages with only nitrite and those with only Aloe vera extract compared to control respectively. The lowest TBARS (68% reduction) were obtained in Aloe vera extract and nitrite incorporated sausages (Tukey HSD, P < 0.05). Result showed that the use of Aloe vera extract and nitrite combination in sausage formulation is a useful approach to control lipid oxidation in the product. Supplementary information: The online version contains supplementary material available at 10.1007/s13197-021-05183-5.

Isolation, identification and determination of technological properties of the halophilic lactic acid bacteria isolated from table olives.

Isolation, identification and technological properties of halophilic lactic acid bacteria (HLAB) from olive samples which were collected from different places in Turkey were examined in the present work. According to the genetic analysis of the isolates, it was determined that 42 (%57.53) Lactobacillus plantarum, 20 (%27.39) Lactobacillus acidipiscis, 7 (%9.58) Enterococcus faecium, 2 (%2.73) Lactobacillus alimentarius, 1 (%1.36) Lactobacillus farciminis, 1 (%1.36) Lactobacillus namurensis. L. plantarum, L. alimentarius, L. farciminis and L. namurensis were able to tolerate 8% NaCl. Twenty-seven isolates showed lipolytic activity between 0.2 and 1.09 U ml-1. Thirty isolates had pectolytic activity as 3.24-5.29 U ml-1. A total of twelve L. acidipiscis, L. alimentarius, L. farciminis and L. plantarum strains showed positive decarboxylase activity by decarboxylating tyrosine. Results indicated that L. plantarum Z64A, Z64B, Z66A, Z83B, Z100A and L. acidipiscis Z112D showed high salt resistance, no biogenic amine production, low pectinolytic and low lipolytic activity. HLAB are dominant bacteria in the fermented foods containing high levels of salt. There are no many studies about the presence of HLAB in table olives and their technological properties. The present work showed that HLAB isolates of L. plantarum, L. acidipiscis and E. faecium were the predominant species found in table olives collected from the western part of Turkey. The selected strains which have high salt resistance, low pectinolytic and lipolytic activity are potentially good candidates as starter culture source in olive fermentations.

In-vitro microbial production of conjugated linoleic acid by probiotic L. plantarum strains: Utilization as a functional starter culture in sucuk fermentation.

Twenty-three probiotic Lactobacillus plantarum strains were screened in-vitro to determine their ability to produce conjugated linoleic acid (CLA). L. plantarum AA1-2 and L. plantarum AB20-961 were identified as potential strains for CLA production. Optimum conditions for these strains to produce high levels of CLA were determined by evaluating the amount of added hydrolyzed sunflower oil (HSO) and initial pH levels in a nutrient medium. The highest CLA production was obtained in medium with pH6.0 and 2% HSO (P<0.05). Those strains were then used as starter culture in sucuk fermentation. Five sucuk treatments included a control (no starter culture), two sucuk groups with L. plantarum AA1-2 at the initial pH of 5.8 or 6.0 and two sucuk groups with L. plantarum AB20-961 at the initial pH of 5.8 or 6.0. Results indicate that L. plantarum AB20-961 produced higher amount of CLA in sucuk at initial pH of 5.8 and 6.0 levels during first 24h of fermentation compared with other groups. CLA isomer concentration decreased in all sucuk groups during the rest of the fermentation period (P<0.05) and remained quite stable during the storage. This study demonstrated that probiotic L. plantarum AB20-961 can be used in sucuk manufacturing without posing any quality problems.

Ultrasound in the meat industry: general applications and decontamination efficiency.

This review summarizes the findings of research focused on ultrasound as a "green", nonchemical technology in the meat industry to improve meat quality and safety. An overview of the importance of the decontamination in meat processing and microbial inactivation using ultrasound combined with some other applications is provided along with results of high power ultrasound studies which have been applied and adapted in the meat industry. The research results revealed that ultrasound by itself or in combination with other processing and/or preservation methods has a potential for improving the general quality, marination and tenderness of meat, preventing microbial growth and recontamination in meat and meat products as well as for the determination of defects in carcasses and cleaning process equipment. This review will provide an interpretation of ultrasound applications, an up-to-date summary of published articles, and an overview of the microbial inactivation in meat and poultry and their products by ultrasound. Since there is a need for not only a pathogen-free product but also a quality product; this review also can be accepted as a report on the results of research in the field of meat quality improvements with ultrasound applications.

Identification of lactic acid bacteria isolated from the fecal samples of healthy humans and patients with dyspepsia, and determination of their ph, bile, and antibiotic tolerance properties.

The research of novel probiotic strains is important in order to satisfy the increasing request of the market and to obtain functional products in which the probiotic cultures are more active and have better probiotic characteristics than those already on the market. In this study, the probiotic potential of Lactobacillus and Enterococcus strains isolated from human feces was investigated. One hundred seven strains of lactic acid bacteria were isolated from the fecal samples of 19 adult volunteers with stomach problems and the fecal samples of 12 healthy adult volunteers. The strains were identified by 16S rRNA analysis and examined for resistance to gastric acidity (pH 3.5) and bile salts (0.3% bile salt). The antibiotic susceptibility of the strains was also determined. The counts of lactic acid bacteria in the fecal samples ranged from 1.7 x 10(7) to 3.1 x 10(10) CFU/g. The species present in those samples were found to be Lactobacillusplantarum, L. fermentum, Enterococcus faecium and E. durans. Results indicated that L. plantarum (AA1-2, AA17-73, AC18-88, AK4-11, and AK7-28), L. fermentum (AB5-18, BB16-75, and AK4-180), E. faecium (AB20-98 and BK11-50) and E. durans (AK4-14 and BK9-40) showed good pH and bile tolerance. These strains are potentially good candidates for use as health-promoting bacteria.