• Journal of Dairy Science and Biotechnology
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• v.36 no.2
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• pp.106-120
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• 2018

Since 2018, the production and sales of ram-milk cheese ripened for over 60 days has been permitted in South Korea. Hence, this study aimed to examine the microbiological changes in 7 different types of Gouda cheese. During the aging period, traditional raw-milk Gouda Cheeses 1 and 2 did not contain Salmonella spp. during the 60-day storage period and no E. coli after 20-day storage. Coliform bacteria were not detected in Cheese 1 after 40 days; however, they were detected in Cheese 2 up to 60 days. Salmonella spp. were inhibited during the 60-day storage period in Cheese 3 (Salmonella spp.-contaminated raw-milk Gouda cheese), Cheese 4 (Cheese 3 contaminated with lactic acid bacteria DH 5 isolated from Kefir) and Cheese 5 (Cheese 3 contaminated with lactic acid bacteria DN1 isolated from Kefir). In particular, inhibition of Salmonella spp. was more prominent in Cheese 4 and Cheese 5 than in Cheese 3. During 60-day storage, Cheese 6 had a significantly reduced lactic acid bacteria. Furthermore, in Cheese 7, E. coli, E. Salmonella ssp. were rarely detected, and lactic acid bacteria were slightly greater in Cheese 7 than in other cheeses during the 60-day period. Moreover, all samples from Cheese 1 to Cheese 7 were not contaminated with Listeria monocytogenes, Staphylococcus aureus, Clostridium perfringens, and E. coli O157:H7.

• Journal of Dairy Science and Biotechnology
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• v.36 no.2
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• pp.95-105
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• 2018

Since 2018, the Korean government has permitted the production and sale of any cheese made from raw milk and aged for at least 60 days. The present study aimed to investigate the sensory characteristics of various types of Gouda cheese produced from raw milk during 60-day aging. The average pH of the raw milk used in this experiment was $6.7{\pm}0.4$, similar to that of the sterilized milk. The pH of raw-milk Gouda cheese was $5.2{\pm}0.5$ a day after the 60-day aging period, wherein the pH was $5.5{\pm}0.3$. In total, 5 samples were used for sensory evaluation in this experiment: Cheeses 1~5. With respect to flavor, Cheeses 1 and 5 received the highest and lowest scores, respectively. Raw-milk Gouda cheese produced using Salmonella spp.-contaminated raw milk was not greatly influenced by flavor; however, it had a negative effect on its appearance. In the future, it is imperative to carry out sensory evaluation of cheese produced with raw milk contaminated with various food-contaminating bacteria.