Yusuf Biçer, Gonca Sönmez, Gamze Turkal, Tahir Yilmaz, M. Hüdai Çulha, Gürkan Uçar
Authentication of fresh goat cheese by TaqMan based real-time PCR
Nachweis von frischem Ziegenkäse durch TaqMan-basierte Real-Time PCR
The most prevalent form of adulteration found in milk and dairy products involves the addition of cow milk to goat milk and dairy products. Detecting such adulteration is crucial in order to prevent health issues, particularly allergies, and to safeguard consumers against financial losses. This research aimed to examine the extent of cow and goat milk mixing at various percentages: 100%, 90%, 75%, 25%, 10%, 5%, 1%, and 0%. To accomplish this, fresh cheese samples were experimentally produced using these milk mixtures, and the levels of cow milk percentage and cow DNA content were determined using TaqMan real-time PCR. The results indicated that the presence of cow milk mixed with goat milk at concentrations as low as 1% and with cow DNA levels of 0.01 ng could be detected in cheese samples. In conclusion, TaqMan-based real-time PCR demonstrates high sensitivity and can be regarded as a reliable method for identifying the presence and proportions of cow milk in cheese samples obtained through the blending of cow and goat milk, thereby ensuring protection against economically driven adulteration and promoting consumer safety.
Didem Akpınar Kankaya, Banu Özden Tuncer, Yasin Tuncer
Safety assessment of Lactobacilli isolated from foods of animal origin
Sicherheitsbewertung von aus Lebensmitteln tierischen Ursprungs isolierten Laktobazillen
In this study, lactobacilli strains that were isolated from different foods of animal origin were identified at the species level and investigated for antibiotic resistance, virulence factors, biofilm, and biogenic amine production characteristics. According to the results of the 16S rDNA sequence analysis, thirty isolates were identified as 22 w, three Lacticaseibacillus paracasei subsp. tolerans, two Latilactobacillus sakei subsp. sakei, one Lacticaseibacillus rhamnosus, one Limosilactobacillus fermentum, and one Lactilactobacillus curvatus. By disk diffusion test, all strains were found to be resistant to at least one antibiotic. Most of the strains were found resistant to vancomycin (90%), followed by cefoxitin (86.67%) and norfloxacin (66.67%). The only vanX gene (93.33%, 28/30) was detected in strains, but no other antibiotic resistance genes were detected in any of the strains. PCR findings revealed the presence of the acm (3/30, 10%) and efaAfs (1/30, 3.33%) genes in strains, but other virulence factor genes were not detected in any of the strains. The biofilm production genes were not found in any of the isolates. Only the tyrosine decarboxylase gene tdc was found in Lactilactobacillus curvatus DYB17, which dexarcoxylates tyrosine.
Ali Samet Babaoğlu, Hatice Berna Poçan, Tudi Ainiwaer, Hayriye Özkan,
Esra Korkmaz Mutlu, Mustafa Karakaya
Assessment of garlic and onion powder as natural antioxidant on the physico-chemical properties, lipid-protein oxidation and sensorial characteristics of beef and chicken patties during frozen storage
Bewertung des Einflusses von Knoblauch- und Zwiebelpulver als natürliche Antioxidantien auf die physikalisch-chemischen Eigenschaften, die Lipid-Protein-Oxidation und die sensorischen Merkmale von Rind- und Hühnerfleischpasteten während der Gefrierlagerung
The aim of this study was to evaluate the antioxidant effect of garlic and onion powder in beef and chicken patties during frozen storage for 120 days. Three different groups were produced for each type of meat (beef and chicken): beef and chicken patties without garlic and onion powder (control groups) (BC and CC), beef and chicken patties with garlic powder added at 0.70% (BG and CG), beef and chicken patties with onion powder added at 0.70% (BO and CO). The samples were analysed for pH, lipid and protein oxidation, colour and sensory properties. With the exception of the samples containing onion powder, the TBARS numbers of BC, CC, BG and CG increased during frozen storage and the highest TBARS numbers were determined on days 60, 90 and 120 (P < 0.05). The total protein carbonyl content of CG and CO did not change with the progression of frozen storage (P > 0.05). The addition of garlic powder preserved the a* value of beef patties during storage. The onion powder significantly improved oxidative stability by reducing TBARS number and total carbonyl content of beef and chicken patties (P < 0.05), while garlic powder had no significant effect on lipid and protein oxidation (P > 0.05). The beef patties with onion powder had a higher flavour score than the samples with garlic powder (P < 0.05). The garlic powder reduced the flavour and overall acceptance score of the chicken patties compared to the control group of chicken patties (P < 0.05). These results suggest that onion powder was an effective natural additive in terms of oxidative stability of beef and chicken patties and improved sensory properties.