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Microbiological status of bulk tank milk and different flavored gomolya cheeses produced by a milk producing and processing plant
73-78Views:275The microbiological quality of milk is important not only for food safety, but it can also influence the quality of dairy products. In this study, our aim was to assess the microbiological status of the bulk milk of a milk-producing farm, and some natural and flavored (garlic, dill, onion) gomolya cheeses made from pasteurized milk produced by their own processing plant. We determined the number of coliform bacteria, Escherichia coli, Staphylococcus aureus, and molds of three milk and eight cheese samples. The tests were conducted between July and September, 2017.
In bulk milk, the mean coliform count was 3.83±0.17 log10 CFU/ml; the mean E. coli count was 1.38±0.14 log10 CFU/ml; the mean mold count was 3.74±1.30 log10 CFU/ml; and the S. aureus count was <1.00 log10 CFU/ml, respectively. The mean coliform count in gomolya cheeses was 3.69±1.00 log10 CFU/g; the mean E. coli count was 2.63±0.58 log10 CFU/g; the mean S. aureus count was 3.69±1.35 log10 CFU/g and the mean mold count was 1.74±0.37 log10 CFU/g. The amount of coliforms detected in different flavored gomolya cheeses were significantly different (P<0.05). More than 10 CFU/g of E. coli was found only in the dill flavored cheeses, and S. aureus was found only in dill (3.66±1.86 log10 CFU/g) and onion (3.71±0.52 log10 CFU/g) flavored gomolya cheeses. Based on the obtained results, it was found that the amount of coliform bacteria and E. coli in bulk milk exceeded the limit set in regulation of the Hungarian Ministry of Health (MoH) 4/1998 (XI. 11.) and the amount of S. aureus was below the limit. For gomolya cheeses, the S. aureus count exceeded the limit. The amount of coliform bacteria remained above the limit in cheeses, except for the garlic flavored gomolya cheese. In cheeses, a larger E. coli count was detected than in the bulk milk, but there is no specific limit for cheeses in the regulation. The mold count exceeded the limit specified in the regulation in cheeses, but a lower value was detected relative to milk.
The results show that, in the case of bulk milk and gomolya cheeses, certain detected quantities exceeded the limit values set forth in regulation of MoH 4/1998 (XI. 11.). The results indicate an inadequate microbiological state of the raw material and the finished products. The reasons for these are due to reduced technological hygiene or the inappropriate handling of raw material and finished products. In this study, we have summarized the results of our preliminary studies, which can provide a basis for further hygiene studies.
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The effect of sous-vide cooking on the antioxidant properties of oyster mushroom (Pleurotus ostreatus L.)
177-184Views:165Oyster mushrooms (Pleurotus ostreatus L.) are renowned for their antioxidant, antimicrobial, and prebiotic properties. This study explores the antioxidant characteristics, activity, and β-glucan content in freeze-dried mushroom samples, investigating the influence of sous-vide cooking. Uncooked freeze-dried P. ostreatus and three pre-cooked freeze-dried samples (70, 80, 90 °C through 4 hours) were analysed for Total Polyphenol Content (TPC), Total Flavonoid Content (TFC), Radical Scavenging (DPPH), Ferric Reducing Antioxidant Power (FRAP), and β-glucans content via HPLC and Total Dietary Fiber (TDF) via enzymatic gravimetric method. Results indicate that uncooked mushroom powder exhibited superior antioxidant capabilities compared to cooked samples. The sous-vide cooked (80 °C) mushrooms displayed the highest total phenolic and flavonoid content. Moreover, pre-cooked (70 °C) mushroom powder demonstrated the highest β-glucan content, significantly surpassing the uncooked control sample. Notably, pre-cooked groups (80, 90 °C) demonstrated significantly higher TDF levels compared to uncooked sample. This research offers valuable insights into the potential use of mushrooms as high-antioxidant, antimicrobial, and prebiotic food or feed supplements, with broad implications across various fields.