Tolga Kahraman

Microbiological and chemical quality of tahini halva

Purpose – This paper aims to determine the microbiological and chemical quality of halva samples obtained from retail markets and producers in the Marmara region.Design/methodology/approach – Halva samples (120) were collected at intervals between March 2007 and February 2008. Samples were investigated for the microbiological (aerobic bacteria, Staphylococcus aureus, coliform bacteria, Escherichia coli, molds/yeasts, Salmonella spp. and staphylococcal enterotoxins) and chemical (sesame oil, protein, moisture, ash content, tahini, acidity, total sugar content and peroxide values) quality.Findings – Overall, 36.66 per cent (44/120) tahini halva samples were of unacceptable quality based on recommended criteria of microbiological (39 of 120, 32.5 per cent) and chemical quality (21 of 120, 17.5 per cent) by the Turkish Food Codex. Salmonella spp. and staphylococcal enterotoxins were not determined in the samples.Originality/value – Tahini halva, which is one of the oldest traditional desserts and is popular i...

Effect of muscle stretching on meat quality of biceps femoris from beef.

The objective of this study was to examine the effect of muscle stretching on meat quality and ultrastructure of biceps femoris (BF) from beef. After slaughter, the right side of the carcasses were suspended from the Achilles tendon (AS; n=10), while the left sides were re-hanged from the pelvic bone (PS; n=10). Meat quality was evaluated by water holding capacity (WHC), cooking loss (CL), color, shear force (SF) and sarcomere length (SL). As a result, PS had no impact on WHC, CL and color parameters. PS significantly decreased SF values by 7.5% only at 2 days postmortem. At pelvic suspended sides, SL was increased by 0.13 μm, 0.14 μm and 0.12 μm at 2, 7 and 10 days postmortem, respectively (P<0.001). Electron microscopy showed that the ultrastructure of BF have longer sarcomeres and smaller fiber diameter after PS. In conclusion, PS is a useful method for improving tenderness by stretching muscles.

Effect of rosemary essential oil and modified-atmosphere packaging (MAP) on meat quality and survival of pathogens in poultry fillets

The effect of rosemary (Rosmarinus officinalis L.) essential oil (REO) and modified-atmosphere packaging (MAP) on the survival of certain pathogens (Salmonella Typhimurium and Listeria monocytogenes) in poultry fillets and on their meat quality during 7 days of refrigerated storage were investigated. Because REO at 0.05% and 0.1% had weak antibacterial activity and REO at 0.3%, 0.5% and 1.0% imparted unacceptable organoleptic properties, only REO at 0.2% was used to treat the poultry meat. The results showed that adding 0.2% REO to poultry fillets did not reduce the size of the population of S. Typhimurium and L. monocytogenes. However, REO treatment significantly decreased the L* (lightness) value and increased the a* (redness) value of stored fillets, and adding REO in combination with MAP reduced the level of lipid oxidation. In conclusion, in a suitable combination, REO can be applied to improve the quality of meat, but further studies should be conducted to determine the appropriate commercial level for different meat products.

Microbiological evaluation of food contact surfaces at red meat processing plants in Istanbul, Turkey

Abstract A microbial survey was performed for different red meat processing plants produces retail cuts and ground beef in Istanbul, Turkey. Swab samples from 10 cm2 of surface were obtained from food contact surfaces and environmental surfaces. Total mesophilic aerobic count (TMC), coliform count (CC), Escherichia coli count (ECC) and Escherichia coli O157:H7 were determined for each sample. Average surface counts for TMC from floor, wall, food contact surfaces were between 2.71 to 3.15 log10 CFU / cm2, 0.69 to 1.56 log10 CFU/cm2 , 2.23 to 3.0 log10 CFU/cm2 respectively. Coliforms and Escherichia coli were determined from floor and food contact surfaces. Samples taken from four different wall were negative for Escherichia coli. Any E. coli O157:H7 counts were observed at the samples. Microbial testing for red meat processing plants is one of the most important subject for identifying and monitoring potential hazards as part of HACCP and GMP programs.

Prevalence of Salmonella spp. and Listeria monocytogenes in different cheese types produced in Turkey

Purpose – The present paper seeks to determine the prevalence of Salmonella spp. and Listeria (L.) monocytogenes in several cheese varieties.Design/methodology/approach – A total 280 cheese samples (105 white cheese, 70 processed cheese, 45 dil cheese and 60 kasar cheese) purchased from supermarkets in six provinces of Turkey were collected at intervals between March 2007 and February 2008.Findings – The results showed that 1.9 percent of white cheese samples were contaminated with Salmonella spp, whereas the L. monocytogenes prevalence was 4.8 percent in this type of cheese sample. The prevalence of L. monocytogenes in processed cheese and kasar cheese were found to be 1.4 percent and 1.7 percent, respectively. No Salmonella spp. was isolated from these cheese varieties. Neither Salmonella spp. nor L. monocytogenes were found in dil cheese samples examined.Originality/value – Cheese is a ready to eat product that with a low incidence of contamination may pose great public health concerns. Microbiological...

Electron microscopy of contractile bands and quality characteristics in high-voltage electrical stimulation broiler breast meat

In this study, 20 broilers were used to examine the effect of high-voltage electrical stimulation (HVES) on meat quality and the microstructure of the pectoralis muscle. After slaughter, carcasses were randomly distributed into 2 treatment groups (n = 10). In the first group, carcasses were electrically stimulated (500 V, 100 Hz) for 60 s. Carcasses in the second group (nonelectrical stimulation) were used as a control. Meat quality was evaluated by the rate of pH, water-holding capacity, cooking loss, color (L*, a*, b*), shear force, and sarcomere length. As a result, HVES increased the rate of muscle pH decline (P < 0.001). High-voltage electrical stimulation had no effect on water-holding capacity and cooking loss values. Only L* (lightness) values were improved during the storage time (P < 0.01). Tenderness (P < 0.001) and sarcomere length (P < 0.05) values were significantly increased at 2 and 5 d postmortem. In addition, microstructure examination demonstrated that the stimulated muscles had longer sarcomeres; however, the A-, I-, and Z-bands and the mitochondrial membrane structure were intact in HVES and nonelectrically stimulated carcasses. The results showed that HVES is a useful method for improving the tenderness of broiler breast meat.

Differential Expression Analysis of Meat Tenderness Governing Genes in Different Skeletal Muscles of Bovine: Differential Expression Analysis of Meat Tenderness Governing Genes in Different Skeletal Muscles of Bovine

BACKGROUND The aim of this study was to compare 12 different skeletal muscles of bovine (n = 15) with each other in terms of tenderness and meat-quality-related gene expressions. Tenderness values were evaluated by shear force, and ANK1, CAPN1, CAST, HSPB1, HSPA1A gene expressions were analyzed by using quantitative real-time polymerase chain reaction. RESULTS ANK1 gene showed significant differences between tender and tough muscles (P < 0.001) and was found to be more closely related to meat quality than CAPN1. No difference was found for CAST, HSPB1, and HSPA1A gene expressions between different parts of skeletal muscles (P > 0.05). The results also showed that the most convenient skeletal muscle for the meat quality studies is musculus psoas major. Furthermore, comparative use of musculus longissimus thoracis and musculus extensor digitorum muscles may give the most accurate results, rather than using other muscle groups in comparative studies between tender and tough muscles. CONCLUSION ANK1 gene is a preferable biomarker for the determination of meat quality, and CAPN1 needs further studies. However, CAST, HSPB1, and HSPA1A genes may not be suitable biomarkers for the determination of meat quality based on this study.