Effect of nano‐TiO2‐LDPE packaging on microbiological and physicochemical quality of Pacific white shrimp during chilled storage

Nano‐TiO₂‐modified low‐density polyethylene (NTLDPE) packaging was prepared by blending LDPE with nano‐TiO₂. The effects of NTLDPE packaging on quality of Pacific white shrimp during storage at 4 °C were investigated. Results showed that NTLDPE lowered the K value by 28.50%, while increased sensory score by 30.77% in comparison with the control. NTLDPE packaging retarded the decrease of whiteness and water holding capacity and the increase of melanosis score based on the signs of freshness and deterioration of shrimp. Furthermore, NTLDPE packaging reduced total viable counts (TVC) by 6.42% and total volatile basic nitrogen (TVB‐N) contents were 14.82% lower than that of control. TVB‐N content and TBARS value, as well as polyphenol oxidase activity and TVC, were maintained and shrimp remained a commercial acceptability for 8 days. The overall results indicated that NTLDPE packaging could preserve the quality and extend the shelf‐life of Pacific white shrimp.     

Effect of O2 scavenger on the shelf‐life of catfish (Pangasius sutchi) steaks during chilled storage

BACKGROUND: Active packaging for preserving meat products, including seafoods, has been gaining importance in recent times. The present study was undertaken to assess the effectiveness of O₂ scavenger, the most widely used active packaging technology, on the shelf‐life of catfish steaks in chilled storage conditions. RESULTS: O₂ scavenger was effective in reducing the oxygen concentration inside the packaging to as low as 0.42% within 24 h. This reduction in oxygen in O₂ scavenger packages showed positive effects on quality parameters compared to control air packs. Total volatile base nitrogen (TVB‐N), thiobarbituric acid value and peroxide value of catfish steaks packed in O₂ scavenger was significantly different (P < 0.05) compared to air‐packed samples. Based on the sensory, microbiological and TVB‐N values, the control samples were acceptable only up to 10 days, compared to 20 days in O₂ scavenger‐packed samples, extending the shelf‐life by 10 days. CONCLUSION: O₂ scavenger reduced the oxygen concentration inside the package significantly within 24 h compared to control air packs. By using this technique, the use of a vacuum packing machine can be avoided. Further, O₂ scavenger extended the product's shelf‐life up to 20 days, compared to 10 days in control packs. Copyright © 2007 Society of Chemical Industry     

Comparative studies of quality changes in white and dark muscles from common carp (Cyprinus carpio) during refrigerated (4 °C) storage

Differences between white and dark muscles from common carp (Cyprinus carpio) in sensory assessment, total viable counts (TVC), total volatile basic nitrogen (TVB‐N), pH, electrical conductivity (EC), biogenic amines (BAs), nucleotide degradation products and colours were investigated under air and vacuum conditions during refrigerated (4 °C) storage. Compared with white muscle, dark muscle had a higher lipid content, but lower crude protein and moisture content. TVC, TVB‐N, pH, and L* value were higher in white muscle, while K value and a* value were higher in dark muscle. Under both conditions, white and dark muscles had significant (P < 0.05) differences in tyramine and cadaverine content. Although dark muscle was significantly (P < 0.05) lower in ATP content, it had higher rate of IMP degradation and K value increase. Taking sensory and microbial indexes into consideration, dark muscle appeared to have a longer shelf life than white muscle under both conditions.     

Quality changes and microbiological spoilage analysis of air‐packed and vacuum‐packed silver carp (Hypophthalmichthys molitrix) fillets during chilled storage

The effects of air‐packed (AP) and vacuum‐packed (VP) on quality and microbial characteristics of silver carp (Hypophthalmichthys molitrix) fillets during chilled storage (4 ± 1 °C) were investigated. The fillets were analyzed for sensory scores, total volatile basic nitrogen (TVB‐N), ATP‐related compounds (ATP, IMP, HxR, and Hx), K value, and biogenic amines (BAs). The results proved that VP inhibited the increase of microorganisms, TVB‐N, Hx, and putrescine in silver carp, and slowed the reduction in sensory score. Therefore, VP can be applied for preservation of the silver carp fillets to improve its quality. For identification, 16S rRNA genes of the isolated pure strains were sequenced and analyzed. On the initial day of storage, Chryseobacterium was the dominant bacterial genus. At the end of shelf life, Pseudomonas was the most common group in AP fillets and Aeromonas followed by Yersinia were found mainly in VP samples.

Practical applications

Silver carp (Hypophthalmichthys molitrix) are distributed widely in fresh water systems. The world aquaculture production of silver carp was 4,354,638 tons, and it ranked second highest among freshwater fish species in 2015, but they are perishable during storage because of microbial spoilage and biochemical reactions. Vacuum packaging (VP) has proved to be effective for extending the shelf‐life of aquatic products by excluding oxygen that prevents the growth of spoilage bacterial. However, little information is available on the microbial succession of VP silver carp. Therefore, this work was to determine the differences of microbiological succession on chilled silver carp fillets under air‐packed (AP) and VP conditions using a combination of culture‐based and 16S rRNA gene analysis methods. Furthermore, this study will give valuable information about development and spoilage of VP silver carp fillets.     

Quality changes in sea urchin (Strongylocentrotus nudus) during storage in artificial seawater saturated with oxygen, nitrogen and air

BACKGROUND: Sea urchin gonads are highly valued seafood that degenerates rapidly during the storage period. To study the influence of dissolved oxygen concentration on quality changes of sea urchin (Strongylocentrotus nudus) gonads, they were stored in artificial seawater saturated with oxygen, nitrogen or air at 5 ± 1 °C for 12 days. RESULTS: The sensory acceptability limit was 11–12, 6–7 and 7–8 days for gonads with oxygen, nitrogen or air packaging, respectively. Total volatile basic nitrogen (TVB‐N) values reached 22.60 ± 1.32, 32.37 ± 1.37 and 24.91 ± 1.54 mg 100 g^?1 for gonads with oxygen, nitrogen or air packaging at the points of near to, exceeding and reaching the limit of sensory acceptability, indicating that TVB‐N values of about 25 mg 100 g^?1 should be regarded as the limit of acceptability for sea urchin gonads. Relative ATP content values were 56.55%, 17.36% and 18.75% for gonads with oxygen, nitrogen or air packaging, respectively, on day 2. K‐values were 19.37%, 25.05% and 29.02% for gonads with oxygen, nitrogen or air packaging, respectively, on day 2. Both pH and aerobic plate count values showed no significant difference (P > 0.05) for gonads with the three treatments. CONCLUSION: Gonads with oxygen packaging had lower sensory demerit point (P < 0.05) and TVB‐N values (P < 0.05), and higher relative ATP content (P < 0.01) and K‐values (P < 0.05), than that with nitrogen or air packaging, with an extended shelf life of 4‐5 days during storage in artificial seawater at 5 ± 1 °C. Copyright © 2011 Society of Chemical Industry     

Effects of E‐beam irradiation and vacuum packaging on biogenic amines formation in common carp (Cyprinus carpio) fillets

The effects of vacuum packaging followed by E‐beam irradiation treatment on the shelf life of common carp (Cyprinus carpio) fillets were studied by measuring biogenic amines and sensory analysis. Samples were irradiated at doses of 0.10, 0.50, 1.0 and 2.0 kGy. Putrescine, cadaverine, histamine and tyramine showed very good correspondence with the irradiation dose and the time of storage. Spermine, spermidine, tryptamine and phenylethylamine did not show statistically significant changes with the time of storage. According to the sensory assessment and biogenic amines index (BAI), the shelf life of unirradiated common carp fillets was found to be approximately seven days. The 1 and 2 kGy irradiation doses extended the shelf life of samples up to 66 and 77 days, respectively. High values of correlation coefficients (r < ?0.86) between BAI and sensory evaluation indicated that BAI could be considered as a quality indicator of common carp fillets.     

Evaluation of Shelf Life of Superchilled Cod (Gadus morhua) Fillets and the Influence of Temperature Fluctuations During Storage on Microbial and Chemical Quality Indicators

Quality changes of aerobically packed cod fillets stored under superchilling and abusive temperature conditions were characterized by the growth of specific spoilage organisms (SSO) and the production of microbial metabolites measured by an electronic nose along with traditional sensory and chemical analysis (total volatile basic nitrogen [TVB‐N], pH). A new process based on quick contact freezing and cold air blasting was used to achieve superchilling of fillets before chilled (0.5 °C) or superchilled (‐1.5 °C) storage. Photobacterium phosphoreum dominated under temperature abusive conditions coinciding with high levels of TVB‐N and increased electronic nose responses indicating increased levels of alcohols and aldehydes at sensory rejection. Dominating growth of Pseudomonas spp. in 1 batch was associated with the origin, the catching method, and the cooling conditions during processing. The superchilling process followed by superchilled storage (‐1.5 °C) extended the sensory shelf life of the fillets for at least 3 d compared with traditional process, resulting in a total shelf life of 15 d. High content of TVB‐N was observed in superchilled fillets at sensory rejection. P. phosphoreum counts were lower under superchilling conditions (6.0 to 6.8 log colony‐forming units [CFU]/g), compared with the traditionally processed chilled fillets (7.2 log CFU/g). However, H₂S‐producing bacteria appeared to grow steadily under superchilling conditions reaching counts as high as 7.6 log CFU/g at sensory rejection.     

Combination of bulk storage in controlled and modified atmospheres with modified atmosphere packaging system for chilled whole gutted hake

Whole gutted hake placed in boxes of ice were kept in modified and controlled atmospheres for 12 days with the gas mixture 60%CO₂/15%O₂/25%N₂ (v/v/v) at 2 ± 1 °C. Each lot of hake was then subdivided into two other lots and these were packed on trays, some of them in air and some in the same mixture of gases. The trays were kept at 2 °C until spoilage. The shelf‐life of the hake stored in these conditions was assessed by physical (pH), chemical (TVBN (total volatile basic nitrogen) and TMA‐N (trimethylamine nitrogen)) and sensory (inspection and taste panel) analyses. The results of these analyses indicated that the control lot (stored in air throughout) was rejected before the lots kept in adjusted atmospheres. However, the taste panel accepted all the lots, including the control lot, after 24 days of storage. The sample which was kept at 2 °C in a controlled atmosphere for 12 days and then packed in a modified atmosphere of the same gas mixture did not exceed pH 7 after 31 days of storage, nor the limits of TVBN and TMA‐N of 40 and 12 mg per 100 g respectively. As regards oxidative rancidity, TBA (2‐thiobarbituric acid) levels were very low under all storage conditions and did not exceed 2.5 mg malonaldehyde per 100 g muscle. According to the results of this study, bulk storage of whole gutted hake in boxes in ice under a controlled atmosphere could be combined with later packaging in a modified atmosphere on trays stored at 2 °C to extend the shelf‐life of the hake. © 2001 Society of Chemical Industry     

包装方式对四角蛤蜊卤制风味产品贮藏品质的影响

目的：研究不同包装方式对其贮藏期品质的影响。方法 对四角蛤蜊卤制风味产品进行普通包装、真空包装、30% CO2+70% N2、50% CO2+50% N2、30% N2+70% CO2气调包装,并在4 ℃贮藏条件下,测定菌落总数、质构特性、色差、TVB-N值、风味特性等理化指标,选择最佳的包装方式。结果 普通包装样品在第3 d、真空包装组样品在第6 d时菌落总数超标,而气调包装组的货架期可达12 d左右。气调包装组的硬度、弹性、咀嚼性的下降程度都低于普通包装和真空包装组,气调包装的护色效果也优于其他两组。气调包装对TVB-N值、TBA值、pH值变化的延缓作用明显优于真空包装和普通包装。结论 不同包装方式对四角蛤蜊卤制风味产品贮藏品质的保持能力依次为气调包装、真空包装、普通包装,其中50% CO2+50% N2气调包装保鲜效果最佳,能显著延长产品货架期。     

Biogenic and volatile amines in Chinese mitten crab (Eriocheir sinensis) stored at different temperatures

Biogenic amines, total volatile base nitrogen (TVB‐N) and trimethylamine nitrogen (TMA‐N) concentrations in the muscle of postmortem Chinese mitten crab stored at 4 and 20 °C were studied. Among five biogenic amines, histamine, tyramine, tryptamine, putrescine and cadaverine, histamine was the main biogenic amine formed during the storage time and reached highest levels of 91.22 mg kg^?1 after 72 h at 4 °C and 181.23 mg kg^?1 after 24 h at 20 °C. Histamine could be used a safety index for crab. The levels of other biogenic amines were less than 10 mg kg^?1 and fluctuated with storage time. TVB‐N and TMA‐N levels did not change greatly throughout 72 h storage at refrigerated temperature. TVB‐N and TMA‐N were not considered to be reliable indicators of the freshness of crab.     

Combined effect of MAP and active compounds on fresh blue fish burger

The combined effects of three essential oils [thymol, lemon extract and grapefruit seed extract (GFSE)] and modified atmosphere packaging conditions (MAP) on quality retention of blue fish burgers was studied and discussed. In particular, samples were packaged in air and in three different gas mix compositions: 30:40:30 O₂:CO₂:N₂, 50:50 O₂:CO₂ and 5:95 O₂:CO₂. During a 28-day storage period at 4 °C, the nutritional, microbiological and sensorial quality of the packed products was assessed. The potential development of biogenic amines was also evaluated.The obtained results highlight the possibility to improve the microbial quality of blue fish burgers by using very small amount of thymol (110 ppm), GFSE (100 ppm) and lemon extract (120 ppm) in combination with MAP. Based primarily on microbiological results, the combined use of the tested natural preservatives and a packaging system characterized by a high CO₂-concentration, was able to guarantee the microbial acceptability of fish burgers until the 28th day of storage at 4 °C. On the other hand, results from sensory analyses showed that sensorial quality was the sub-index that limited the burgers shelf life (to about 22–23 days), even if the proposed strategy was also effective in minimizing the sensory quality loss of the product having no effect on its nutritional quality.     

Microbial spoilage analysis and its effect on chemical changes and shelf‐life of Norway lobster (Nephrops norvegicus) stored in air at various temperatures

Microbial activity and spoilage of Norway lobster (Nephrops norvegicus) from Greek temperate waters, stored in air at 20, 5 and 0 °C was assessed. Microbial spoilage population, Total Volatile‐Base Nitrogen (TVB‐N), Trimethylamine‐Nitrogen (TMA‐N), pH and organoleptic changes were determined. Shelf‐life of Norway lobster stored at 20, 5 and 0 °C was 24, 72 and 96 h respectively. The product was spoiled due to the development of TVB‐N and melanosis of the carapace, as TVB‐N was apparent from the early stages of storage and correlated very well with microbial growth and shelf‐life. Pseudomonas sp. was the predominant spoilage bacterium. Product rejection coincided with TVB‐N levels of 330–400 mg kg^?1 and Pseudomonas sp. population level of about 5 × 10⁵ cfu g^?1. Pseudomonas sp. and TVB‐N are presumably the Specific Spoilage Organism and the Chemical Spoilage Index of the product.     

Shelf-Life Extension of Fresh Ready-to-Bake Pizza by the Application of Modified Atmosphere Packaging

Combined effects of modified atmosphere packaging (MAP) and refrigeration (7±1 °C) were studied on shelf-life extension of ready-to-bake pizza. The gas atmospheres in the present study included four variables, namely viz. MAP1, air (control); MAP 2, 100% CO₂; MAP 3, 100% N₂; and MAP 4, 50%CO₂/50%N₂. The effect of MAP variables was observed for moisture content, water activity, pH, titratable acidity, free fatty acids, peroxide value, thiobarbituric acid, tyrosine content, lycopene content and L* a* b* values. The results indicated that MAP with 100% CO₂ significantly inhibited the lipid oxidation, reduced proteolysis and prevented total acidity (less decrease in pH). Also, the MAP (MAP 2) showed preservative effect on colour indices and shelf life higher than other treatments. Sensory analysis showed that the control samples had a limited shelf life of 5 days while a significant increase in shelf life of 15 days (300% increase) was achieved under modified atmospheres for unbaked pizza samples.     

Quality changes of farmed cobia steaks held in cold stores (−18 °C)

Cobia (Rachycentron canadum) steaks held in cold store (?18 °C) were analysed aseptically in triplicates for the sensory, total aerobic bacterial count, proximate composition, pH, thiobarbituric acid‐reactive substance (TBA‐RS), formaldehyde, total volatile base nitrogen (TVB‐N), trimethyl amine‐nitrogen (TMA‐N), salt soluble nitrogen (SSN), nonprotein nitrogen (NPN), sodium dodecyl sulphate‐poly acrylamide gel electrophoresis (SDS‐PAGE) pattern. Steaks were sensorially acceptable up to 5 months of storage and the total bacterial counts did not exceed 6 log CFU counts. There were no significant changes in the pH values. TBA‐RS values increased significantly (P < 0.05) and reached 7.34 mg of malonaldehyde kg^?1 fat at the end. Formaldehyde content remained constant upto 4th month and later increased to 2.06 μg g^?1 (P < 0.05). TVB‐N and TMA‐N values did not exceed the acceptable limits. NPN contents showed no change, while SSN contents increased to 1.24% after 5 months. SDS‐PAGE pattern indicated no protein denaturation in the fish tissue. Results indicated that TBA‐RS value can only be considered as the valuable indicator in determining the quality of fish steaks held in cold stores.     

Changes in biogenic amine levels during storage of Mexican-style soft and Spanish-style dry-ripened sausages with different aw values under modified atmosphere

Two raw sausages were prepared: a soft and a dry-ripened one, both by local traditional and industrial manufacturing practices. Sausages were packaged under a CO₂/N₂ atmosphere at different targeted activity water (a_w) values: 0.96 and 0.92 (soft sausages) and 0.88 and 0.82 (dry-ripened sausages). Sausages were then stored at 5 °C for 42 days or at 12 °C for 240 days (soft and a dry-ripened sausages, respectively). The time-related changes in dominant microbiota, pH and biogenic amine contents during storage were determined. Tyramine was the most abundant biogenic amine in all the sausages. Biogenic amine levels were higher in dry-ripened sausages than in soft sausages at packaging. However, during refrigerated storage soft sausages were fermented and the levels of biogenic amines increased (P < 0.05). At the end of storage, traditional soft sausages with 0.96 a_w presented comparable levels of biogenic amines to traditional dry-ripened sausages.     

Modified atmosphere packaging of filleted rainbow trout

Shelf‐lives of filleted rainbow trout (Oncorhynchus mykiss) packaged in over‐wrap, vacuum and gas mixture conditions and stored at 1 ± 1 °C were compared by measurement of pH, total volatile bases (TVB), hypoxanthine content, lipid oxidation (TBARS value), superficial counts of aerobic psychrotrophic flora and sensory analysis (colour, odour and flavour). The gas mixtures evaluated were 10% O₂ + 50% CO₂ + 40% N₂, 10% O₂ + 50% CO₂ + 40% Ar, 20% O₂ + 50% CO₂ + 30% N₂, 20% O₂ + 50% CO₂ + 30% Ar, 30% O₂ + 50% CO₂ + 20% N₂ and 30% O₂ + 50% CO₂ + 20% Ar. Sensory quality deterioration was delayed and bacterial growth as well as increases in pH, TVB and hypoxanthine levels were reduced by modified atmosphere packaging (MAP). Lipid oxidation was higher in gas packages with 20 and 30% O₂ than in those with 10% O₂. Vacuum‐packed fillets presented the lowest TBARS values. In summary, MAP gave rise to a significant extension of shelf‐life when compared with vacuum and over‐wrap packaging. No significant differences were found between the packages containing either N₂ or Ar. The best evaluated atmosphere consisted of 10% O₂ + 50%CO₂ + 40% N₂/Ar. © 2002 Society of Chemical Industry     

Shelf‐Life Extension of Chill‐Stored Beef Longissimus Steaks Packaged under Modified Atmospheres with 50% O2 and 40% CO2

This study was conducted to compare the shelf‐life of beef steaks stored in different packaging conditions: overwrapped (OW) packaging and 2 modified atmosphere packaging systems (MAP): 80% O₂ MAP (80% O₂/20% CO₂) and 50% O₂ MAP (50% O₂/40% CO₂/10% N₂). Steaks were stored at 2 °C for 20 d. Headspace gas composition, microbial counts, color stability, pH, purge loss, and lipid oxidation were monitored. Among the packaging types, 50% O₂ MAP was superior to OW packaging and 80% O₂ MAP in delaying bacterial growth and extending shelf‐life to 20 d. 50% O₂ MAP also gave steaks an acceptable color during storage. No significant differences were observed in color stability of steaks packaged in both 50% O₂ MAP and 80% O₂ MAP. This study reveals 50% O₂ MAP is a realistic alternative to preserve beef steaks efficiently.     

Impact of the O2 Concentrations on Bacterial Communities and Quality of Modified Atmosphere Packaged Pacific White Shrimp (Litopenaeus Vannamei)

The importance of spoilage‐related bacteria in fresh Pacific white shrimp (Litopenaeus vannamei) under different modified atmospheres (MAs) at 4 °C and the effect of O₂ were demonstrated in the current study. The changes of bacterial communities in MA‐packed shrimp during cold storage were studied by a combined method of plate counts with isolation and identification. Three gas mixtures were applied: 80% CO₂/5% O₂/15% N₂, 80% CO₂/10% O₂/10% N₂ and 80% CO₂/20% O₂, and unsealed packages of shrimp were used as the control. In addition, the TVB‐N, pH, whiteness index, and sensory scores were also determined to evaluate the quality changes of shrimp. MA packaging effectively inhibited the increase of total psychrotrophic bacteria counts and H₂S‐producing bacteria counts by about 1.7 and 2.1 log cycles, respectively. The growth of Gram‐negative spoilage bacteria in shrimp, including Shewanella spp., Aeromonas spp., and Pseudomonas spp., was inhibited by MA packaging, but the growth rate of Gram‐positive bacteria such as lactic acid bacteria (LAB) and Brochothrix spp. were less affected by MA as effectively as Gram‐negative bacteria. In comparison with the MA‐packaged samples, the counts of H₂S producers in shrimp under a CO₂‐enriched atmosphere with 20% O₂ were slightly lower than the count in samples under an atmosphere with 5% O₂. However, MA with 20% O₂ led to higher concentrations of TVB‐N, and lower whiteness values and sensory scores. The shelf life of shrimp under 80% CO₂/10% O₂/10% N₂ has been prolonged by > 6 d in comparison with the control according to the sensory scores.     

Application of Electronic Nose for Measuring Total Volatile Basic Nitrogen and Total Viable Counts in Packaged Pork During Refrigerated Storage

The objective of this study was to predict the total viable counts (TVC) and total volatile basic nitrogen (TVB‐N) in pork using an electronic nose (E‐nose), and to assess the freshness of chilled pork during storage using different packaging methods, including pallet packaging (PP), vacuum packaging (VP), and modified atmosphere packaging (MAP, 40% O₂/40% CO₂/20% N₂). Principal component analysis (PCA) was used to analyze the E‐nose signals, and the results showed that the relationships between the freshness of chilled pork and E‐nose signals could be distinguished in the loadings plots, and the freshness of chilled pork could be distributed along 2 first principal components. Multiple linear regression (MLR) was used to correlate TVC and TVB‐N to E‐nose signals. High F and R² values were obtained in the MLR output of TVB‐N (F = 32.1, 21.6, and 24.2 for PP [R² = 0.93], VP [R² = 0.94], and MAP [R² = 0.95], respectively) and TVC (F = 34.2, 46.4, and 7.8 for PP [R² = 0.98], VP [R² = 0.89], and MAP [R² = 0.85], respectively). The results of this study suggest that it is possible to use the E‐nose technology to predict TVB‐N and TVC for assessing the freshness of chilled pork during storage.     

Microbiological,physicochemical and sensory characteristics of Cameros cheese packaged under modified atmospheres

This study evaluated the shelf-life quality of Cameros cheeses packaged under modified atmospheres. Five different modified atmosphere conditions were studied (carbon dioxide/nitrogen mixtures and vacuum). Control cheeses were packaged in air. The product stored at 3–4°C was evaluated periodically to investigate its sensory quality, microbiological condition and physicochemical characteristics. Weight loss and pH evolution were similar in vacuum and air packaging. Cheeses packaged in 100% CO₂showed the greatest weight losses and lower pH values. CO₂reduced proteolysis and lipolysis during storage in all conditions studied. Fat acidity and NPN/TN values were slightly higher in vacuum than in CO₂, but lower than in air. Modified atmosphere packaging presented an extended shelf life. Those containing CO₂reduced the growth rate of mesophiles, psychrotrophs, Enterobacteriaceae and coliforms, which was lower when the CO₂concentration increased. The lowest microbial counts were at 100% CO₂while vacuum conditions presented microbial counts only slightly lower than the controls. Salmonella spp.,Staphylococcus aureus and Listeria spp. were not found in any of the samples. Faecal coliforms, moulds and yeasts were not detected under CO₂atmospheres or in vacuum. After 7 days of storage, the sensory characteristics of the control cheeses were unacceptable in all the parameters studied. However, the overall score for cheeses stored in 40% and 50% CO₂did not change substantially, retaining a reasonable acceptability until the end of the storage period. The 100% CO₂atmosphere had a very negative effect on sensory quality. With regard to Cameros cheese, packaging in 50%CO₂/50%N₂and 40%CO₂/60%N₂are the most effective for extending shelf life and retaining good sensory characteristics.