Kaşar peynirinde üretim ve olgunlaşma aşamalarının listeria monocytogenes üzerine etkisi
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Date
2000
Authors
Çetinkaya, Figen
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Publisher
Uludağ Üniversitesi
Abstract
Bu çalışma, ülkemizde yaygın olarak tüketilen kaşar peynirlerinde farklı üretim, olgunlaşma ve depolama koşullarında Listeria monocytogenes' in peynirin mikroflorasma ve kimyasal özelliklerine bağlı olarak gelişimini incelemek amacıyla gerçekleştirildi. Bu amaçla, 3.43, 4.71, 5.22 ve 6.45 log kob/ml düzeyinde L.monocytogenes inokule edilen çiğ sütlerden ve etkenin 3.25, 4.21, 5.52 ve 6.41 log kob/ml seviyelerinde inokule edildiği pastörize sütlerden kaşar peynirleri üretildi. Çiğ sütten yapılan peynirlerin farklı üretim aşamalarında ve olgunlaşmanın 1., 10., 30., 60., 90. ve 120. günlerinde; pastörize sütten yapılan peynir örneklerinin ise üretim aşamalarında ve 6±l°C'de depolamanın 1. ve 7.günlerinde L.monocytogenes sayıları tespit edildi. Ayrıca, gerek çiğ sütten gerekse pastörize sütten yapılan kaşar peynirlerinin üretim, olgunlaşma ve depolama aşamalarında meydana gelen mikrobiyolojik ve kimyasal değişiklikler incelendi. Çiğ sütten üretilen l.grup peynirlerde haşlama işlemi sonrasında, 2. ve 3. grup peynir örneklerinde ise sırasıyla olgunlaşmanın 60. ve 90.günlerinde etkene rastlanmadı. 4.grup peynir örneklerinde L.monocytogenes'in olgunlaşma boyunca canlılığını koruduğu ve 120.günde 1.83 log kob/g düzeyinde olduğu belirlendi. Pastörize sütten üretilen l.grup kaşar peynirlerinde depolama sonunda L.monocytogenes saptanamazken, 2., 3. ve 4.grup peynirlerde sırasıyla 2.74 log kob/g, 3.48 log kob/g ve 4.53 log kob/g düzeylerinde olduğu ortaya konuldu. Çiğ sütten yapılan peynirlerde olgunlaşma sonunda aerob mezofil genel canlı sayıları 5.36-6.44 log kob/g, laktobasiller 7.08-7.40 log kob/g, laktokok-streptokoklar 5.25-5.76 log kob/g, psikrofîl bakteriler 5.04-5.59 log kob/g, maya ve küfler 3.41-3.91 log kob/g arasında bulunurken, koliform bakterilere rastlanmadı. Pastörize sütten üretilen kaşar peynirlerinde depolama sonunda aerob mezofil genel canlı sayıları 2.19-3.33 log kob/g, laktobasiller 6.83- 7.75 log kob/g, laktokok-streptokoklar 6.54-7.85 log kob/g, psikrofîl bakteriler 3.14-4.54 log kob/g arasında belirlenirken, koliform bakteriler ile maya ve küfler saptanamadı. Çiğ sütten üretilen kaşar peynirlerinde olgunlaşmanın 120.gününde pH değerleri 5.30- 5.43, asitlik değerleri (L.A.) %0.81-1.01, kurumadde miktarları %66.28-67.56, kurumaddede yağ miktarları %37.77- 40.08, kurumaddede tuz miktarları ise %4.97-5.23 arasında tespit edildi. Pastörize sütten üretilen peynirlerde depolama sonunda pH değerleri 5.00-5.10, asitlik IVdeğerleri (L.A.) % 1.1 8- 1.24, kurumadde miktarları %57.11- 60.08, kurumaddede yağ miktarları %43.46- 45.71, kurumaddede tuz miktarları ise %4.51- 4.94 arasmda saptandı. Sonuç olarak, kaşar peynirlerinde üretim aşamaları gerek L.monocytogenes gerekse diğer mikrobiyal flora üzerinde gerçek anlamda bir kontrol noktası oluşturmamış, 4 ay süre ile olgunlaştırma işleminin L.monocytogenes' in kontrolü bakmundan önemli olduğu ortaya konmuştur. Starter kültür kullanılarak pastörize sütten üretilen kaşar peynirlerinde, L.monocytogenes' in sekonder kontaminasyonuna karşı gerek peynir üretim aşamaları gerekse vakum paketleyerek 6±l°C'de 7 gün depolanması etken üzerinde etkili olmamıştır. Sütün pastörizasyonu mikrobiyal florada önemli bir azalmaya neden olurken, L.monocytogenes tamamen elimine olduğundan, kaşar peyniri yapımında kullanılacak sütün pastörizasyonunun zorunluluğu ortaya çıkmıştır.
This study was performed to investigate the growth changes of Listeria monocytogenes in kashar, a highly consumed cheese in our country, in relation to the microflora of the cheese and its chemical properties, during different production, ripening, and storage conditions. For this, kashar cheese was produced from raw and pasteurized milk, inoculated with L.monocytogenes in 3.43, 4.71, 5.22,6.45 log cfu/ml and 3.25, 4.21, 5.52, 6.41 cfu/ml, respectively. L.monocytogenes counts were determined in different production steps, on the days 1,10, 30, 60, 90, and 120 of the ripening period of the cheese produced from raw milk; and in the production steps, at the first and the 7th day of the storage at 6±1°C of the cheese produced from pasteurized milk. Also, microbiological and chemical changes occured during the production, ripening and storage steps were investigated on the kashar cheese produced from either raw or pasteurized milk. L. monocytogens was not isolated from the 1st group cheese samples produced from raw milk, after stretching, and on the days 60 and 90 of the ripening periods of 2nd and 3rd group cheese, respectively. L.monocytogenes was determined to survive during the ripening period, and was at the level of 1.83 log cfu/g, on day 120 in the 4th group cheese samples. While no L.monocytogenes was isolated from the 1st group kashar cheese produced from pasteurized milk at the end of the storage period, it was found in the levels of 2.74 log cfu/g, 3.48 log cfu /g and 4.53 log cfu /g in the 2nd, 3rd and the 4th group cheese, respectively. While general aerob mesophile, lactobacilli, lactococci-streptococci, psychrophylic bacteria, and yeast and mold counts were 5.36-6.44 log cfu /g, 7.08-7.40 log cfu/g, 5.25-5.76 log cfu/g, 5.04-5.59 log cfu/g, 3.41-3.91 log cfu/g, respectively, in the end of the ripening period of the cheese produced from raw milk, no coliforms were detected. In the kashar cheese produced from pasteurized milk, general aerob mesophile, lactobacilli, lactococci- streptococci, and psychrophylic bacteria counts were 2.19-3.33 log cfu /g, 6.83-7.75 log cfu/g, 6.54-7.85 log cfu/g, 3.14-4.54 log cfu/g, respectively, in the end of the ripening period of the cheese produced from raw milk, no coliforms were detected, and yeast and mold. From the cheese produced from raw milk, on the day 120 of the ripening period, pH value, acidity (L. A.) value, dry matter amount, fat amount in dry matter, salt amount in dry VImatter were determined as 5.30-5.43, 0.81-1.01 %, 66.28-67.56 %, 37.77-40.08 %, 4.97-5.23 %, respectively. From the cheese produced from pasteurized milk, in the end of the storage period, pH value, acidity (L. A.) value, dry matter amount, fat amount in dry matter, salt amount in dry matter were determined as 5.00-5.10, 1.18-1.24 %, 57.1 1-60.08 %, 43.46-45.71 %, 4.51-4.94 %, respectively. As a result, it was determined that the production steps in the kashar cheese did not form a real control point in the L.monocytogenes counts and on the oher microbial flora levels, and that the ripening for 4 months was important for the control of L.monocytogenes. Neither the production steps or by vacuum packaging and storing at 6±1°C' for 7 days did not have any inhibitory effect against the secondary contamination of L.monocytogenes in the kashar cheese produced from pasteurized milk by the addition of starter culture. Since milk pasteurization caused a significant decrease in the microbial counts, and totally eliminated L.monocytogenes counts, the milk to be used in the production of kashar cheese should be pasteurized.
This study was performed to investigate the growth changes of Listeria monocytogenes in kashar, a highly consumed cheese in our country, in relation to the microflora of the cheese and its chemical properties, during different production, ripening, and storage conditions. For this, kashar cheese was produced from raw and pasteurized milk, inoculated with L.monocytogenes in 3.43, 4.71, 5.22,6.45 log cfu/ml and 3.25, 4.21, 5.52, 6.41 cfu/ml, respectively. L.monocytogenes counts were determined in different production steps, on the days 1,10, 30, 60, 90, and 120 of the ripening period of the cheese produced from raw milk; and in the production steps, at the first and the 7th day of the storage at 6±1°C of the cheese produced from pasteurized milk. Also, microbiological and chemical changes occured during the production, ripening and storage steps were investigated on the kashar cheese produced from either raw or pasteurized milk. L. monocytogens was not isolated from the 1st group cheese samples produced from raw milk, after stretching, and on the days 60 and 90 of the ripening periods of 2nd and 3rd group cheese, respectively. L.monocytogenes was determined to survive during the ripening period, and was at the level of 1.83 log cfu/g, on day 120 in the 4th group cheese samples. While no L.monocytogenes was isolated from the 1st group kashar cheese produced from pasteurized milk at the end of the storage period, it was found in the levels of 2.74 log cfu/g, 3.48 log cfu /g and 4.53 log cfu /g in the 2nd, 3rd and the 4th group cheese, respectively. While general aerob mesophile, lactobacilli, lactococci-streptococci, psychrophylic bacteria, and yeast and mold counts were 5.36-6.44 log cfu /g, 7.08-7.40 log cfu/g, 5.25-5.76 log cfu/g, 5.04-5.59 log cfu/g, 3.41-3.91 log cfu/g, respectively, in the end of the ripening period of the cheese produced from raw milk, no coliforms were detected. In the kashar cheese produced from pasteurized milk, general aerob mesophile, lactobacilli, lactococci- streptococci, and psychrophylic bacteria counts were 2.19-3.33 log cfu /g, 6.83-7.75 log cfu/g, 6.54-7.85 log cfu/g, 3.14-4.54 log cfu/g, respectively, in the end of the ripening period of the cheese produced from raw milk, no coliforms were detected, and yeast and mold. From the cheese produced from raw milk, on the day 120 of the ripening period, pH value, acidity (L. A.) value, dry matter amount, fat amount in dry matter, salt amount in dry VImatter were determined as 5.30-5.43, 0.81-1.01 %, 66.28-67.56 %, 37.77-40.08 %, 4.97-5.23 %, respectively. From the cheese produced from pasteurized milk, in the end of the storage period, pH value, acidity (L. A.) value, dry matter amount, fat amount in dry matter, salt amount in dry matter were determined as 5.00-5.10, 1.18-1.24 %, 57.1 1-60.08 %, 43.46-45.71 %, 4.51-4.94 %, respectively. As a result, it was determined that the production steps in the kashar cheese did not form a real control point in the L.monocytogenes counts and on the oher microbial flora levels, and that the ripening for 4 months was important for the control of L.monocytogenes. Neither the production steps or by vacuum packaging and storing at 6±1°C' for 7 days did not have any inhibitory effect against the secondary contamination of L.monocytogenes in the kashar cheese produced from pasteurized milk by the addition of starter culture. Since milk pasteurization caused a significant decrease in the microbial counts, and totally eliminated L.monocytogenes counts, the milk to be used in the production of kashar cheese should be pasteurized.
Description
Keywords
Kaşar peyniri, Kimyasal bileşim, Listeria monocytogenes, Mikrobiyal flora, Kashar cheese, Chemical composition, Microbial flora
Citation
Çetinkaya, F. (2000). Kaşar peynirinde üretim ve olgunlaşma aşamalarının listeria monocytogenes üzerine etkisi. Yayınlanmamış doktora tezi. Uludağ Üniversitesi Sağlık Bilimleri Enstitüsü.