Changes in the microbiological and chemical characteristics of an artisanal, low‐fat cheese made from raw ovine milk during ripening

Abstract

Changes in the microbial flora of batzos cheese made from raw ovine milk were studied during ripening. Lactic acid bacteria and Enterobacteriaceae were the predominant groups of micro‐organisms. Cheeses manufactured in summer had higher microbial counts than those made in spring, with the exception of staphylococci. Nevertheless, Enterobacteriaceae and coliforms decreased more rapidly in cheese made in summer and counts at the end of storage were lower than those in spring cheese. Enterococci predominated in the ripened curd of cheese made in spring, whereas lactobacilli were the most abundant lactic acid bacteria in cheese made in summer. Enterococcus faecium was the predominant species in spring, and Lactobacillus paracasei ssp. paracasei predominated in cheese made in summer. The pH of the cheeses was > 5.0 throughout ripening, and NaCl‐in‐moisture content (> 8.0%) permitted the growth and survival of salt‐tolerant micro‐organisms. αs1‐Casein degraded at a faster rate than β‐casein; both caseins were hydrolysed more rapidly in spring than in summer. The free amino acid content became higher in summer cheese (566.24–3460.25 µg/g of glycine equivalent) than in spring cheese because of the progress of ripening. Moreover, the milk fat of the cheese was degraded more in the summer than in the spring. The results suggest that there could be advantages to using starter cultures and improving the level of hygiene during milk and cheese production in order to eliminate undesirable micro‐organisms and standardize cheese quality.

Cheese Production Using Kefir Culture Entrapped in Milk Proteins

“…Notably, similar or even higher counts of coliforms, enterobacteria, and staphylococci have been previously reported for other traditional Greek [22,23] and Portuguese [24] cheeses which had been salt treated. The depletion of sugars, the low pH, and the lack of oxygen, due to the metabolic activity of kefir culture, may have also resulted in reduction of their numbers [25].…”

Evaluation of Freeze-Dried Kefir Coculture as Starter in Feta-Type Cheese Production

“…Both unsalted kefir cheese and unsalted rennet cheese were preserved at room and low temperatures. Although microbial counts of total aerobic bacteria, coliforms, enterobacteria, yeasts, lactococci, and lactobacilli did not result in any substantial differences between the two types of cheese and similar types previously reported (21,28,41,44,50), staphylococcus counts were significantly lower in unsalted kefir cheese, not only compared to rennet cheese but more importantly compared to similar cheeses which had been salt treated (21,50).…”

Characteristics of Batzos cheese made from raw, pasteurized and/or pasteurized standardized goat milk and a native culture

“…Raw milk cheeses have a very different microflora at the genus level, as well as in terms of species composition within the same genus (Fontecha et al, 1990;Nikolaou, Tzanetakis, Litopoulou-Tzanetaki, & Robinson, 2002;Psoni, Tzanetakis, & Litopoulou-Tzanetaki, 2003). The main purpose of milk pasteurization is the elimination of pathogens, even though a post-pasteurization contamination may occur.…”

“…For this reason, the cheese is ''hitted'' vigorously during coagulation, in order to exclude in the whey as much fat as possible (Nikolaou et al, 2002;Psoni et al, 2003). The study of the microbiological characteristics of Batzos cheese from raw goat milk made throughout the whole lactation season (Psoni et al, 2003) suggested the need of improving milk quality and handling of milk and cheese and/or employing starter, in order to regulate the growth of undesirable microorganisms, Enterobacteriacae and coliforms.…”