Serkan Kemal Büyükünal

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...

Antimicrobial effects of curcumin against L. monocytogenes, S. aureus, S. typhimurium and E. coli O157:H7 pathogens in minced meat.

The aim of this study was to determine the antimicrobial efficacy of curcumin, one of the active components of the Curcuma longa (turmeric) plant, against food pathogens in a minced meat medium. Salmonella Typhimurium ATCC 14028, Listeria monocytogenes ATCC 7644, Escherichia coli O157:H7 ATCC 33150 and S. aureus ATCC 25923 strains were used as food pathogens. Minimum inhibitory concentrations (MICs) were determined using the macrodilution method. MIC values for curcumin were found to be 125 μg/ml for L. monocytogenes and S. aureus, and 250 μg/ml for S. Typhimurium and E. coli O157:H7. Food pathogens were added to the minced meat at 104 CFU/g (including the control group) and curcumin at doses of 0.5%, 1% and 2% (except the control). The curcumin-supplemented minced meat and control were analysed 0–7 days later. At the end of seven days, it was seen that the 2% dose of curcumin had lowered L. monocytogenes and S. aureus counts by approximately 3 log CFU/g, and E. coli O157:H7 and S. Typhimurium counts by approximately 2 log CFU/g; the 1% dose had lowered L. monocytogenes, S. aureus, E. coli O157:H7 and S. Typhimurium counts by approximately 2 log CFU/g; and that the 0.5% curcumin dose had lowered L. monocytogenes and S. aureus count by approximately 2 log CFU/g, and E. coli O157:H7 and S. Typhimurium count by approximately 1 log CFU/g. Changes in bacterial counts were found to be statistically significant (P ≤ 0.05). It was observed that antibacterial effect increased in direct proportion to dose, while sensory approval decreased. In this study, 0.5% and 1% curcumin doses were determined to be sensorily acceptable. It was concluded that, in view of the scientific benefits and antimicrobial efficacy of curcumin, it may be used instead of, or in smaller doses together with preservative additives in foods where colour change is not important.