Mustafa Gürses

Isolation of moulds capable of producing mycotoxins from blue mouldy Tulum cheeses produced in Turkey

A total of 16 moulds was isolated and identified from 12 blue mouldy Tulum cheeses collected from retailers in Erzurum, Turkey; 12 were Penicillium roqueforti and 4 were Geotrichum candidum. The P. roqueforti isolates were grown in yeast sucrose broth at 5, 12 and 25 degrees C for 10 days, then extracted with chloroform and acetone and the extracts were examined for the presence of patulin, penicillic acid, roquefortine and PR toxin using thin layer chromatography. All of the P. roqueforti strains had toxin-producing ability at 5, 12 and 25 degrees C, eight produced only at 5 and 12 degrees C and six could not produce toxin at 5 degrees C.

Microbiological Characteristics of Part-Baked White Pan Bread During Storage

In this study, white pan breads part-baked 10, 15, and 20 min with and without added calcium propionate were stored at 20°C (room temperature) for 3, 5, and 7 days and at 4°C (refrigerator temperature) for 7, 14, and 21 days. After storage, the baking time of part-baked breads was completed to the baking time of control breads (25 min). Total aerobic mesophylic bacteria (TAMB), coliform bacteria, yeast and mold, and Bacillus spore counts of breads were determined before and after the second baking. While TAMB, yeast and mold counts were 8-log CFU/g in dough, it was measured as 6 and 2-log CFU/g before and after the rebaking process, respectively. Microorganism counts of the part-baked breads without Ca-propionate stored at room temperature increased in significant amounts. However, the second baking process after storage contributed to the re-freshness of breads and decreased the microorganism counts. The levels of water activity (aw) for breads with and without ca-propionate stored at different temperatures and time profiles approximately ranged from 0.92 to 0.89 after the rebaking process and did not significantly affect the microorganism counts. However, addition of calcium propionate in the bread formulation significantly decreased TAMB, coliform bacteria, Bacillus spore, and yeast and mold counts, depending on decrease of pH levels. It was found that the microbiological quality of the rebaking bread with Ca-propionate after part-baking for 10 and 15 mins and storage at both room and refrigerator temperature was much higher than that of the other.In this study, white pan breads part-baked 10, 15, and 20 min with and without added calcium propionate were stored at 20°C (room temperature) for 3, 5, and 7 days and at 4°C (refrigerator temperature) for 7, 14, and 21 days. After storage, the baking time of part-baked breads was completed to the baking time of control breads (25 min). Total aerobic mesophylic bacteria (TAMB), coliform bacteria, yeast and mold, and Bacillus spore counts of breads were determined before and after the second baking. While TAMB, yeast and mold counts were 8-log CFU/g in dough, it was measured as 6 and 2-log CFU/g before and after the rebaking process, respectively. Microorganism counts of the part-baked breads without Ca-propionate stored at room temperature increased in significant amounts. However, the second baking process after storage contributed to the re-freshness of breads and decreased the microorganism counts. The levels of water activity (aw) for breads with and without ca-propionate stored at different temperatu...

A Survey on the Some Chemical and Biochemical Properties of Civil Cheese, a Traditional Turkish Cheese

In this article, 15 randomly selected samples of Civil cheese, were purchased from different retail markets in the Erzurum province, Turkey and were investigated for some chemical and biochemical analyses. All cheese samples were analyzed for dry matter, fat, salt, ash, titrable acidity, total nitrogen, soluble nitrogen, ripening index, αs-and β-casein degradation, γ-casein, and peptides. Dry matter, fat, fat in dry matter, salt, salt in dry matter, ash, and acidity values in samples analyzed were found to be as found between 31.33 and 40.12 g/100 g cheese; 1.00 and 7.00 g/100 g cheese; 2.49 and 18.98 g/100 g cheese; 0.11 and 0.34 g/100 g cheese; 0.27 and 1.04 g/100 g cheese; 1.42 and 5.14 g/100 g cheese and, 0.63 and 2.16%, respectively. TN, WSN/TN, TCA-SN/TN, and PTA-SN/ TN values, expressed as TN%, were found between 3.01 and 5.57 g/100 g cheese, 4.25 and 8.80 g/100 g cheese, 3.23 and 6.12 g/100 g cheese, 1.03, and 5.53 g/100 g cheese in Civil cheese samples analyzed, respectively. SDS-PAGE showed that both αs-CN and β-CN ratios were not high compared with similar cheeses, and are not completely hydrolyzed in all Civil cheese samples. A broad range of values from chemical and biochemical analysis indicated that Civil cheeses collected from retail markets lacked standardization. Consequently, it was decided that Civil cheese samples do not undergo an excessive proteolysis.

Mycotoxin production capability of Penicillium roqueforti in strains isolated from mould-ripened traditional Turkish civil cheese

Mould-ripened civil is a traditional cheese produced mainly in eastern Turkey. The cheese is produced with a mixture of civil and whey curd cheeses (lor). This mixture is pressed into goat skins or plastic bags and is ripened for more than three months. Naturally occurring moulds grow on the surface and inside of the cheese during ripening. In this research, 140 Penicillium roqueforti strains were isolated from 41 samples of mould-ripened civil cheese collected from Erzurum and around towns in eastern Turkey. All strains were capable of mycotoxin production and were analysed using an HPLC method. It was established that all the strains (albeit at very low levels) produced roquefortine C, penicillic acid, mycophenolic acid and patulin. The amounts of toxins were in the ranges 0.4–47.0, 0.2–43.6, 0.1–23.1 and 0.1–2.3 mg kg−1, respectively. Patulin levels of the samples were lower than the others. The lowest level and highest total mycotoxin levels were determined as 1.2 and 70.1 mg kg−1 respectively. The results of this preliminary study may help in the choice of secondary cultures for mould-ripened civil cheese and other mould-ripened cheeses.

Morphological, molecular, and mycotoxigenic identification of dominant filamentous fungi from moldy civil cheese.

Moldy Civil is a mold-ripened variety of cheese produced mainly in eastern Turkey. This cheese is produced with Civil cheese and whey curd cheese (Lor). Civil cheese has had a geographical presence since 2009 and is manufactured with skim milk. In the production of Moldy Civil cheese, Civil cheese or a mixture of Civil and Lor cheese is pressed into goat skins or plastic bags and ripened for 3 months or longer. During the ripening period, natural contaminating molds grow on the surface of and inside the cheese. In this study, 186 mold strains were isolated from 41 samples of Moldy Civil cheese, and 165 of these strains were identified as Penicillium roqueforti. Identification and mycotoxicologic analyses were conducted using morphotypic and molecular methods. PCR amplicons of the ITS1-5.8S-ITS4 region were subjected to sequence analysis. This research is the first using molecular methods on Moldy Civil cheese. Mycotoxicologic analyses were conducted using thin-layer chromatography, and random amplified polymorphic DNA genotypes were determined using the ari1 primer. Of 165 isolates, only 28 produced no penicillic acid, P. roqueforti toxin, or roquefortine.

Effect of Penicillium roqueforti and incorporation of whey cheese on volatile profiles and sensory characteristics of mould‐ripened Civil cheese

In this study, four different types of mould-ripened Civil cheese were manufactured. A defined (nontoxigenic) strain of a Penicillium roqueforti (SC 509) was used as secondary starter for the manufacture of mould-ripened Civil cheese with and without addition of the whey cheese Lor; in parallel, secondary starter-free counterparts were manufactured. A total of 83 compounds were identified. Ketones, alcohols and esters were the principal classes of volatile components. Principal component analysis of the headspace volatiles grouped cheeses by age and type. P. roqueforti inoculated cheese was clearly separated from the other cheeses at 180 days of ripening, and these cheeses were characterised with high levels of ketones (e.g., 2-butanone, 2-heptanone). Differences in the panel scores between the cheese samples were not significant during the first stage of ripening (up to 60 days); as ripening proceeded, these differences were become evident and P. roqueforti inoculated cheeses received higher scores than others. Addition of Lor in the manufacture of mould-ripened Civil cheese caused lower points by the sensory panel, and the cheese inoculated with P. roqueforti and Lor-free was the best type of mould-ripened Civil cheese. The results showed that the use of P. roqueforti in the manufacture of mould-ripened Civil cheese has significant impact on the volatile profiles and sensory attributes.

Lactic Acid Bacteria Isolating From Blue Mouldy Tulum Cheese Produced With Penicillium Roqueforti

A total of 228 lactic acid bacteria colonies were isolated from blue moldy Tulum cheese inoculated with Penicillium roqueforti along with the ripening (4 months). Three different medias (PCA, MRS or M17 agar) were used for isolation, while two API tests were used for identification of LAB. As a result, Enterococcus sp. (53.3%) and Lactobacillus sp. (26.7%) was found as dominant flora at end of ripening. Among them, Enterobacter faecalis (40.0%) and Lactobacillus parabuhneri (13.3%) were determined. The others were also Leuconostoc mesenteroides (10.0%), Pediococcus acetilactici (6.7%) and Lactobacillus bifermentans (6.7%).

Effects of the Different Temperature and Saccharose Concentrations on Some Microbiological and Chemical Characteristics of Medlar Pickle

In the production of medlar pickle was used saccharose concertrations of 0.0%, 30% and 50% as basis of water. Preparing pickles were stored at 10°C and 20°C. During the storage period, the level of acidity and lactic acid bacteria (LAB) counts of pickle samples increased while the levels of pH decreased. This situation was slow in pickles stored at 10°C. The increase of saccharose concentration caused an increase in acidity and LAB count of pickles. The values of the final acidity (%) and pH of the pickles were 1.29 and 3.46, respectively. Lactic acid bacteria counts also increased during the storage period and reached to 108 CFU/ml at the end of 8 weeks. The increase of temperature shortened fermentation duration but mold growth on surface of pickles was abserved.