Anıl Uzun Özcan, Medeni Maskan, Metin Bedir, Hüseyin Bozkurt
Effect of hybrid cooking (ultrasound – ohmic – infrared) method on textural and microbial properties of beefs
Auswirkung einer hybriden Garmethode (Ultraschall – Ohmsch – Infrarot) auf die texturellen und mikrobiellen Eigenschaften von Rindfleisch

Effects of hybrid cooking (ultrasound – ohmic – infrared) and ohmic cooking alone on textural and microbial properties of beef were investigated to get safer and high quality cooked beef. In hybrid cooking, the beef samples pre-treated with ultrasound for 10, 20 and 30 minutes were cooked ohmically at 40, 55 and 70 Volt for 7 minutes, finally infrared cooking was applied to each side of beef at 3 different temperatures (163, 191 and 218 °C) for 3 minutes. Texture profile of beef muscle (hardness, springiness, cohesiveness, gumminess, chewiness, and resilience) was followed during the processing of hybrid and ohmic cooking alone. At hybrid cooking, voltage increment had a significant effect (p<0.05) on hardness, chewiness and gumminess values. On the other hand, generally springiness, cohesiveness and resilience values were not affected significantly (p>0.05) by voltage gradient. After ohmic cooking alone, total aerobic mesophilic bacteria (TAMB) count significantly decreased (p<0.05) from 5.73 to 4.02 log cfu/g, while total coliform (TC) count decreased from 5.01 to below detection limit by increasing voltage level. However, hybrid cooking process was successful for killing of microorganisms as TC and TAMB counts mainly reached well below detection limits. In this study, hybrid cooking can be considered to be more efficient over ohmic cooking alone since it gave synergistic effects with respect to textural properties and provide best microbiological safety and quality of beef.

Asmaa Cherif Anntar, Ibrahim Benamar, Mohamed Salih Barka, Touhami Morghad, Baltasar Mayo, Boumedine Moussa Boudjemaa
Biofilm formation capacities of Staphylo­coccus aureus strains isolated from döner kebab and effect of acetic acid and citric acid against their biofilms
Biofilmbildungsfähigkeit von Staphylococcus aureus-Stämmen isoliert aus ­Döner Kebab und Wirkung von Essig- und Zitronensäure gegen diese Biofilme

Staphylococcus aureus is a well-known food-borne pathogen causing staphylococcal food poisoning with a capacity to develop biofilms on food contact surfaces. This study aimed at evaluating the capacity of S. aureus strains isolated from ready-to-eat döner kebab to produce biofilms on Congo Red Agar (CRA), polystyrene (PST) and stainless steel (SS) surfaces. The effect on S. aureus biofilm forming capacity of glucose, Sodium Chloride (NaCl), temperature and acetic and citric acids was also evaluated. At 37°C temperature and 24 h of incubation, only three out of 11 strains tested produced biofilm on CRA, where as all strains tested were considered either strong or moderate biofilm producers on the surface of both the 96-well PST microtiter plates and SS coupons. On the latter surface, the strength of the biofilm was reduced by increasing the incubation time up to 72 h. Biofilms were quantified by crystal violet staining method after exposing the strains to different concentrations of glucose and NaCl. Results showed that the presence of glucose at any concentration tested promoted S. aureus biofilm formation at 30°C. Increasing the glucose concentration gave better biofilm growth rate at 37°C but at 40°C no significant influence was recorded. For NaCl addition, concentrations greater than 1% did not affect the biofilm formation at both 30 and 37°C. At 40°C, no effect on the bacterial growth rate by increasing concentration. This study showed that increasing acetic and citric acid concentrations up to 2.5% and 4%, respectively enhanced the elimination of 7-days old S. aureus biofilms. Besides, significant reduction was not scored after 5 min of treatment. These results indicate that the environment related conditions could promote S. aureus biofilm formation. Also, they showed that citric and acetic acids can be used as an alternative strategy in eliminating food biofilms.

Berna Kılınç, İrem Kılınç, Çiğdem Takma, Yakut Gevrekçi
Review:
The applications of Fuzzy Logic ­models on food and marine food products
Übersichtsarbeit:
Die Anwendung von Fuzzy-Logik-Modellen auf Lebensmittel und Meeresfrüchte