The effect on shelf life of tulum cheese of modified atmosphere packaging

This study was planned to investigate the effectiveness on the shelf life of tulum cheeses of modified atmosphere packaging (MAP) method and to fill the deficiency found in the literature with the information to be obtained and to present a new product to the market in industrial format. The tulum cheeses produced from pasteurized cow milk were packed in a control group and four different modified atmosphere packaging groups (A = control group (normal atmosphere / dry air), B = 100% CO2, C = 100% N2, D = 70% N2 + 30% CO2 and E = 75% N2 + 25% CO2) in packages of 250 grams. The cheese packages were stored at 4±1 °C. Tulum cheese samples were analyzed for microbiological (total mesophilic aerobic bacteria, Lactobacillus-Leuconostoc-Pediococcus, lactic streptococci, coliform, Enterobacteriaceae, lipolytic bacteria, proteolytic microorganisms, yeast and mold, Escherichia coli, Staphylococcus aureus, sulphate reductive anaerobic bacteria), chemical (pH, acidity, dry matter, salt, ash, oil, water activity, water-soluble nitrogen ratio and degree of ripening, 12% trichloroacetic acid soluble nitrogen ratio (TCA-N), 5% phosphotungstic acid (PTA-N) soluble nitrogen ratio) and sensory (packaging, appearance, structure, smell, taste and total) aspects on days 0., 30., 60., 90., 120., 150., 180., 210. and 240. (except for the 0th day from the sensory side) of storage time. According to the results of microbiological analysis, the total mesophilic aerobic bacteria count began to increase from 0th day of storage in all groups and reached the highest number on different ripening days in each group. It was determined as in the A group (normal atmosphere) was 8.60 ± 0.34 log10 kob / g at the 90th day of storage, in the B group was 9,00 ± 0,18 log10 kob / g at the 120th day of storage, in the C group was 7,91 ± 0,05 log10 kob / g at the 90th day of storage in, the D group 8.44 ± 0.05 log10 kob / g at the 150th day of storage in the E group 8,52 ± 0,14 log10 kob / g at the 240th day of storage. On account of total mesophilic aerobic bacteria, the number in the E group was found to be less than about 1 log the other groups at the 60th and 150th days of storage. Statistically, on 60th, 90th, 120th and 150th days among the groups; in groups B, C, D and E within the group detected significant differences (P<0.05). The samples in A and C groups of 90th day, B group of 120th day, D group of 150th day and E group of 240th day because of spoilage of the products. Lactobacillus-Leuconostoc-Pediococcus counts constantly increased during storage in all groups. The number in the E group was found less than about 2 log at the 60th, 90th and 150th days to of storage compared to the other groups. Statistically, on 60th, 90th and 150th days among the groups; in groups C and E within the group detected significant differences (P<0.05). Lactic streptococcus bacteria counts constantly increased during storage in all groups. The number in the group E was found less than about 1 log from 0th day to 60th day of the storage and about 2 log from the 90th and 120 days of the storage compared to other groups. Statistically, on 0th, 30th, 60th, 90th and 150th days among the groups; in groups B, C and E within the group detected significant differences (P<0.05). Coliform group bacteria and Enterobacteriaceae counts showed a slow steadily decrease throughout the storage time period in all groups. Statistically in coliform group bacteria, in groups B, C, D and E within the group determined significant differences (P<0.05). Statistically in Enterobacteriaceae counts, on 0th day among the groups; in groups A, D and E within the group determined significant differences (P<0.05). There was no growth in A, B, C and D group samples starting from the 90th day and in E group samples from the 60th day. Lipolytic microorganism count in the tulum cheese samples showed a steady increase in all groups from day 0 to the end of the storage period. The numbers in the E group were seen watched less than about 1 log at levels from 120th and 150th days of storage compared to the other groups. Statistically, on 120th and 150th days among the groups; in groups B, C, D and E within the group determined significant differences (P<0.05). Proteolytic bacteria and yeast-mold counts constantly increased during storage in all groups. Statistically, on 60th and 90th days among the groups; in groups A, B, C, D and E within the group determined significant differences (P<0.05). In terms of yeast-mold numbers, the values in group E group were less than about 1-2 log from the 0th day to the end of the storage compared to other groups. Statistically, on 0th, 30th, 60th, 90th, 120th and 90th days among the groups; in groups A, B, C, D and E within the group determined significant differences (P<0.05). Staphylococcus aureus counts decreased during ripening. It was below detectable level as of 90th day of the storage in A and B groups. In groups D and E, these bacteria were not found starting from the first day of the storage. Statistically in groups A, B and C within the group detected significant differences (P<0.05). The numbers of Escherichia coli and sulphide reducing anaerobic bacteria group were below the detectable level (<1,0 log10 kob/g from 0th day of storage in all samples. In experimental tulum cheese samples, the pH values were continuously decreased from 0th. day to the end of the storage in all groups. Acidity (% l.a), dry matter, salt, ash, oil, water activity (aw) value, total protein, water-soluble nitrogen ratio (SÇ-N), water-soluble nitrogen ripening degree 12% trichloroacetic acid soluble nitrogen ratio (TCA-N), 5% phosphotungstic acid (PTA-N) soluble nitrogen ratio values increased continuously during the storage period. Statistically in dry matter amounts, on 150th day among the groups; in groups B and D within the group determined significant differences (P<0.05). Statistically in salt amount ve water activity (aw) value, in group E within the group determined significant differences (P<0.05). Statistically in total protein value, on 150th day among the groups; in group D within the group determined significant differences (P<0.05). Statistically in water-soluble nitrogen ratio (SÇ-N) values, on 30th, 60th and 150th days among the groups; in groups A, B, C, D and E within the group determined significant differences (P<0.05). Statistically in water-soluble nitrogen ripening degree, on 90th and 120th days among the groups; in groups A, B and E within the group determined significant differences (P<0.05). Statistically in 12% trichloroacetic acid soluble nitrogen ratio (TCA-N), on 0th, 30th, 60th, 90th, 120th and 150th days among the groups; in groups A, B, C, D and E within the group determined significant differences (P<0.05). Statistically in 5% phosphotungstic acid (PTA-N) soluble nitrogen ratio values, on 0th, 30th, 60th, 90th, 120th and 150th days among the groups; in groups B, D and E within the group determined significant differences (P<0.05). Looking at the packaging scores, it was determined that all groups showed steadily a decrease from the 30th day of storage. It was observed that external bulging on the 90th days in A and C groups, internal bulging on 120th days in B group. In the D and E groups, neither external nor internal bulging was observed. Statistically in the packaging scores, on 0th, 60th and 90th days among the groups; in groups A, C and E within the group determined significant differences (P<0.05). In terms of appearance scores, while in the A and E groups was observed a continuous decrease since from the 30th day of the storage, in the B, C and D groups were seen to be fluctuating. Statistically in appearance scores, in group A within the group determined significant differences (P<0.05). When evaluated in terms of structure, it was determined that in the A, B and C groups continuously decreased with the progress of the storage of the values (8,00 ± 0,00; 7,78 ± 0,22 and 8,00 ± 0,00) determined on the 30th day of the storage. In the groups D and E, it was seen that the values determined on the 30th day of the storage (8,00 ± 0,00) did not show any change as parallel to the progress of the storage. In terms of smell, taste and total score, the scores taken of the tulum cheese samples decreased continuously from the 30th day of storage. Statistically in the smell scores, in group B within the group determined significant differences (P<0.05). In total, it was determined that taken score A group, 83,08 ± 2,28 on 90th days, in the B group was 82,17 ± 1,36 on the 120th day; in the C group was 83,55 ± 1,26 on the 90th day, in the D group 85,55 ± 0,99 on the 150th day and in the E group 74,22 ± 7,51 on the 240th. Statistically in total scores, in group E within the group determined significant differences (P<0.05). As a result, it was seen that stored at 4°C, packed in 75% N2 + 25% CO2 (E) gas mixture of tulum cheeses prepared in pasteurized cow milk, prepared as 2% starter culture supplement, changes in microbiological, chemical and sensory properties occured at minimum levels and shelf life was extended up to 240 days. In addition, if presented to market packed in 250 grams of the tulum cheeses, no only consumer acceptance will increase but also decrease the waste of the chese in the breakfast tables. Thus, it is thought that this new kind of tulum cheese which is reliable in terms of public health, which can take place in industrial format, markets, the contributions from the positive direction from individual economy to social economy will be provided. Key words: Modified Atmosphere Packaging, Tulum Cheese, Shelf Life, Microbiology, Chemical, Sensory, Quality.