Microbiological changes throughout ripening of Keş cheese

Abstract

Microbiological changes in Keş cheese, traditional Turkish raw cow's milk cheese made without the addition of starter culture, were studied during 90 days of ripening. Physico-chemical parameters, pH, salt content and water activity (aw), as important parameters for microbial growth, were also determined. Lactic acid bacteria were predominant microbial group. The time of ripening significantly influenced the count of total aerobic mesophilic bacteria, psychrophilic bacteria, mould (P<0.05), Lactobacillus spp. and Lactococcus spp. (P<0.01) which increased during ripening. E. coli and coagulase-positive staphylococci were not detected. The counts of Enterococcus spp. (P<0.05), Staphylococcus-Micrococcus spp., Enterobactericeae and coliform bacteria decreased throughout ripening of Keş cheese, which was connected to the physico-chemical parameters. Water activity significantly decreased (P<0.05), while the salt content increased (P<0.01) during ripening of Keş cheese. The obtained results will contribute to the establishment of the microbiological quality standards for Keş cheese and give necessary information for formation of autochthonous starter culture, which will help to understand ripening process of sour dried cheeses and improve the traditional farmhouse cheese production. , Enterobactericeae i koliformnih bakterija smanjivao se tijekom zrenja Keş sira što se može dovesti u vezu sa fizikalno-kemijskim parametrima sira. Aktivitet vode se značajno smanjivao tijekom zrenja Keş sira (P<0.05), dok se udio soli povećavao (P<0.01). Dobiveni rezultati pridonijeti će uspostavljanju mikrobioloških standarda kakvoće Keş sira, pružiti informacije potrebne za definiranje njegove autohtone mikrobne kulture, te pomoći u razumijevanju procesa zrenja kiselinskih sušenih sireva i poboljšanju tradicionalne proizvodnje ovih sireva na malim gospodarstvima.

Effect of preservation method on the microbiological characteristics of white cheese (Gibna bayda) during the storage period

“…The pH of cheese steadily decreased from 5.63±0.03 at day 1 to 2.92±0.03 at day 60. These results are in agreement with those reported by Vrdoljak et al 32 who reported a decrease in pH of soft cheese from 6.28±0.02 at day 6 to 6.20±0.01 at day 15, and Kirdar et al 33 working on Keş cheese, a traditional Turkish raw cow's milk cheese made without the addition of starter culture, found that the pH of cheese decreased from 5.48±0.33 at day 1 to 4.72±0.27 at day 90. Wahba and El-Abbassy 34 reported that the pH values progressively decreased during storage with a pronounced drop in the first month.…”

Microbiological and physicochemical changes during ripening of Camembert cheeses made from raw and pasteurized cow milk produced in Tizi-Ouzou (north of Algeria)

“…The decrease of contamination and the pathogen microflora, during the ripening process of cheese raw milk, is due to the increase in the ripening microflora, which modifies the physicochemical parameters (a w and pH) and releases peptides with antibacterial activity (Fontan et al 2001;Arenas et al 2004;Kirdar et al 2018). However, some studies demonstrated that coliforms decrease during the first week and then increase till the end of the ripening process, with higher rates for the Camembert made Results in the same column for the same parameter with different letters are significantly different at P < 0.05…”

Süt Endüstri̇si̇ Yan Ürünleri̇ İle Üreti̇len Bi̇ber Turşusunun Bazi Kali̇te Parametreleri̇ni̇n Araştirilmasi

“…It was stated that a low pH (4.2-4.6) is not suitable for the growth of the most spoilage bacteria (Robinson et al, 2006), but may promote the growth of yeasts and moulds that may adversely affect the appearance and taste of cheese (Robinson et al, 2002). In the literature, there are various dairy products containing parallel and/or different values to the amount of yeasts and moulds detected in our research (Hayaloglu et al, 2008;Kırdar et al, 2018).…”