Effect of storage temperatures and time on shelf‐life of sliced and modified atmosphere packaged Pastırma,a dried meat product,produced from beef

The effects of modified atmosphere on some physical, chemical and microbiological properties of sliced past?rma made from beef Longissimus dorsi muscle were investigated. Sliced‐past?rma samples (moisture 43.65 ± 0.15%, pH 5.71 ± 0.02) were stored in modified atmosphere packages (50% N₂ + 50% CO₂) at 4 and 10 °C for 150 days. The storage period had a significant effect (p < 0.01) on moisture, pH, thiobarbituric acid reactive substances, free fatty acid, non‐protein nitrogen, water‐soluble nitrogen, colour values and total aerobic bacteria, lactic acid bacteria and Micrococcus/Staphylococcus counts. The storage temperatures (4 and 10 °C) also had a significant effect (p < 0.01) on moisture, pH, thiobarbituric acid reactive subctances, free fatty acid, water soluble nitrogen, a* values, total aerobic bacteria lactic acid bacteria, and Micrococcus/Staphylococcus counts. It was determined that the storage period × the storage temperature interactions had a significant (p < 0.01) effect on the values of pH, a* and the counts of total aerobic bacteria, lactic acid bacteria, Micrococcus/Staphylococcus. It was also observed that the yeast and mold count was the highest in the first storage period and decreased throughout storage. Enterobacteriaceae count was also below the detectable level (<2.00 cfu g^?1) throughout the storage period. Copyright © 2005 Society of Chemical Industry     

Effect of modified atmosphere and vacuum packaging on microbial,chemical and sensory quality indicators of fresh,filleted Sardina pilchardus at 3 °C

The self‐life, quality and safety of refrigerated sardine fillets (Sardina pilchardus) were determined at 3 °C in atmospheric air, vacuum and modified atmosphere (50% CO₂/50% N₂) packaging conditions. Microbiological, physico‐chemical and sensory parameters were utilised as quality indicators. The microbial flora of sardine comprised—according to order of occurrence—Shewanella putrefaciens, pseudomonads, Brochothrix thermosphacta, lactic acid bacteria and, finally, Enterobacteriaceae. Bacteria grew most quickly in sardines stored in air, followed by those in vacuum packaging, and the lowest counts were found in modified atmosphere packaging. The concentrations of moisture, ash, protein, fat and polyunsaturated fatty acids were not affected during the storage period compared to the pH values and the concentrations of lactate and ammonia that showed significant differences. Copyright © 2007 Society of Chemical Industry     

Use of carbon dioxide enriched atmospheres in the refrigerated storage (2 °C) of salmon (Salmo salar ) steaks

 Selected microbial counts (total viable microbiota, Brochothrix thermosphacta, lactic acid bacteria and Enterobacteriaceae), biochemical parameters [pH, total volatile nitrogen, nucleotide breakdown products, non-volatile amines, d(–) and l(+)-lactic acids and short-chain fatty acids] and sensory attributes (colour and odour) of refrigerated (2  °C) salmon (Salmo salar) steaks stored under CO₂-enriched [CO₂/air (20/80, v/v), CO₂/air (40/60, v/v)] and air atmospheres were determined. When compared with air, sensory results showed shelf-life extension of 6 days and 15 days for 20% and 40% CO₂-enriched atmospheres, respectively. Microbial and biochemical results also revealed that the 40% CO₂-enriched atmosphere was the most effective packaging type for refrigerated salmon. Received: 22 April 1999     

Effect of combined application of high pressure treatment and modified atmospheres on the shelf life of fresh Atlantic salmon

High pressure (HP) processing at low temperatures combined with modified atmosphere packaging (MA) was used for the preservation of salmon. A shelf life extension of 2 days was obtained after a HP treatment of 150 MPa for 10 min at 5°C compared to unpressurised, vacuum-packed salmon. MA storage (50% O₂+50% CO₂) alone extended the shelf life of salmon for 4 days at 5°C. When salmon had been subjected to HP treatment in the presence of 50% O₂+50% CO_2, the threshold value for microbial spoilage of salmon (7.0–7.2 log CFU/g) was not reached for at least 18 days at 5°C. Spoilage microorganisms (lactic acid bacteria, Shewanella putrefaciens) as well as pathogens (Listeria monocytogenes Scott A, Salmonella typhimurium) spiked on salmon prior to the treatment, were more susceptible to HP in the presence of 50% O₂+50% CO₂. The mode of action of compressed gases is probably related to intracellular formation of reactive oxygen species as well as to phase transition phenomena. Although microbial growth on salmon was retarded, the combined HP and MA treatments, at the settings used in this study, promoted a detrimental effect on colour and changes in the balance of oxidative rancidity.     

Microbial and physicochemical modifications of hake (Merluccius merluccius) steaks stored under carbon dioxide enriched atmospheres

Microbial counts (total viable, Brochothrix thermosphacta, lactic acid bacteria and Enterobacteriaceae), biochemical parameters [pH, total volatile nitrogen, nucleotide breakdown products, non‐volatile amines, D (−) and L (+) lactic acid and short‐chain fatty acids] and sensory attributes (colour and odour) of refrigerated (2 °C) hake (Merluccius merluccius) steaks under carbon dioxide enriched air (CO₂ /air, 20/80 v/v and CO₂ /air, 40/60 v/v) and air atmospheres were determined. When compared with air, sensory results showed shelf‐life extension of 4 and 11 days for 20% and 40% CO₂‐enriched atmospheres, respectively. Microbial and biochemical results also revealed that the 40% CO₂‐enriched atmosphere was the most effective packaging type for refrigerated hake. © 2000 Society of Chemical Industry     

DISTRIBUTION PACKAGING METHOD AND STORAGE TIME EFFECTS ON THE MICROBIOLOGICAL CHARACTERISTICS AND INCIDENCE OF THE PATHOGENS LISTERIA MONOCYTOGENES AND SALMONELLA IN PORK1

Microbiological and yield characteristics were determined on bone-in pork loins and Boston butts (n = 65 each) that were selected from a commercial facility and subjected to one of three packaging treatments: (1) paper wrapped, (2) modified atmosphere packaging (66% O, 2.26% CO₂ and 8% N₂), and (3) vacuum packaging. Cuts were stored up to 21 days at 0 ± 2C for yield characteristics and an added 28 and 35 days for microbiological characteristics. Treatment and storage effects on the incidence of the pathogens Listeria monocytogenes, Salmonella and numbers of aerobic bacteria, lactic acid bacteria and coliforms were determined. The amount of purge was variable (100 to 500 g) among packaging treatments. The vacuum packaged and modified atmosphere packed pork loins and butts had lower aerobic plate counts (P < .05) compared with the paper wrapped loins and butts. The numbers of Listeria species decreased at a greater rate for the vacuum packaged and modified atmospheric packaged pork loins compared with the paper wrapped loins. No Salmonella were found on meat from any packaging treatment or storage time. The microbial quality of pork loins and butts can be improved by using vacuum packaging compared with paper wrapping or modified atmosphere packaging.     

The sensory and microbiological quality of fresh sliced mushroom (Agaricus bisporus L.) packaged in modified atmospheres

The effect of modified atmospheres, generated by using different packaging films, on the quality of sliced mushrooms was evaluated. The carbon dioxide and oxygen content inside the packages as well as the colour, texture, weight loss, sensory attributes, mesophiles, psychrotrophs, Pseudomonas fluorescens, faecal coliforms, Escherichia coli and anaerobic spores were determined. Modified atmospheres containing 2.5% CO₂ and 10–20% O₂ reduced the microbial counts and improved the mushrooms’ appearance when compared with an air atmosphere. Modified atmospheres containing 15% CO₂ and <0.1% O₂ inhibited mushroom development and toughening and reduced microbial growth. Although these atmospheres had no effect on colour, they did allow the development of off odours and anaerobic spores were detected. No differences in microbial growth or mushroom spoilage were observed under the different moisture contents generated in the packages at 4 °C. Aerobic bacteria counts were considered very high even at the beginning.     

Quality of chilled ready-to-bake pizza stored in air and under modified atmospheres: Microbiological and sensory attributes

Modified atmosphere packaging (MAP) studies on microbiological and sensory analysis were conducted to extend the shelf life of ready-to-bake pizza stored at 7±1°C. The gas combinations used were: atm1: air (control), atm2: CO₂ (100%), atm3: N₂ (100%), atm4: 50% CO₂/50% N₂. Total plate count (TPC), yeasts/molds (Y/M), coliforms, lactic acid bacteria (LAB), psychrotrophs, and anaerobic spore formers were estimated at time intervals of 0, 5, 10, 15, and 20 days. TPC and LAB of pizza samples (atm1) reached 7.10 and 8.14 log CFU/g after 10 days of storage, respectively. Coliforms, psychrotrophs, and Y/M were significantly higher (p<0.05) for pizza samples stored in atm1 than other storage conditions of MAP. Finally, counts of anaerobic spore formers were low (<3 log CFU/g) irrespective of the packaging conditions throughout the entire storage period. It was concluded that among the 4 atmospheres examined, atm2 (100% CO₂) was the best, followed by atm4>atm3>atm1 respectively, in descending order. MAP conditions under this study may extend shelf life of pizza to considerable amount of time.     

气调包装对烤鸭腿货架期及微生物多样性的影响

为延长烤鸭腿货架期、保持其食用品质并阐明烤鸭腿冷藏过程中的菌群演替规律,本实验以托盘包装为对照组,研究了0～4 ℃条件下两种气调包装（100%（体积分数,下同）N2、50% CO2＋50% N2）对烤鸭腿贮藏过程中微生物（菌落总数、乳酸菌数、肠杆菌科数）、硫代巴比妥酸反应产物值及感官特性的影响,并通过高通量测序分析了贮藏过程中烤鸭腿的微生物多样性。结果表明：与托盘包装和100% N2包装相比,50% CO2＋50% N2包装显著抑制了烤鸭腿微生物的生长（P＜0.05）,使其货架期接近21 d,并抑制了其脂肪氧化（P＜0.05）,较好地维持了烤鸭腿的品质和感官特性。贮藏时间和包装方式对贮藏后期烤鸭腿的菌群结构有明显影响,泛菌属、类香味菌属、假单胞菌属和不动杆菌属为50% CO2＋50% N2包装烤鸭腿中的优势菌群,索丝菌属、泛菌属、假单胞菌属、肉食杆菌属和明串珠菌属为100% N2包装烤鸭腿中的优势菌群,优势菌群的不同是导致不同包装方式烤鸭腿间货架期产生差异的主要原因。     

Quality of Atlantic Mackerel (Scomber scombrus L.) Fillets during Modified Atmosphere Storage

Sensory, physical, biochemical and microbial quality were investigated in mackerel fillets stored under CO₂ modified atmosphere packaging (MAP) at -2°C for 21 days. Packaging gas composition remained constant during storage. An experienced sensory panel found seaweedy and cucumber-like odors (raw) decreased whereas sourness corresponded with lactic acid bacteria increase. Both sensory (raw) fillet ‘yellowness’ and Hunter ‘b’ values increased. Visual (cooked) moistness and expressible fluid decreased but no difference was found in cooking losses. Small increases in total volatile base-nitrogen and trimethylamine-nitrogen paralleled aerobic plate counts; ethanol increased linearly. Coliforms, yeasts and molds were detected at < 10 CFU/g. CO₂ MAP storage at – 2°C can maintain Grade 1 shelf-life extension for ≥ 21 days     

Effect of the packaging method and the storage time on lipid oxidation and colour stability on dry fermented sausage salchichón manufactured with raw material with a high level of mono and polyunsaturated fatty acids

The effects of fatty acid composition, two packaging methods (vacuum and 20% CO₂/80% N₂) and storage under refrigeration for 210 days were evaluated on a dry fermented sausage (salchichón), manufactured with raw material enriched in monounsaturated or polyunsaturated fatty acids. Fatty acid composition was determined on sausage mixtures and on ripened sausages and lipid oxidation and colour stability was determined on ripened sausage at different times during storage. The modification of fatty acid composition of the sausages raised the nutritional quality, slightly affecting the colour properties. Dry fermented sausages enriched in polyunsaturated and monounsaturated fatty acids presented higher lipid oxidation values than the control ones. Both packaging methods (vacuum and 20% CO₂/80% N₂) during 210 days of chilled storage had minor effects on the colour and the lipid oxidation stability.     

A dissolving CO2 headspace combined with organic acids prolongs the shelf-life of fresh pork

The aim of this paper was to evaluate the effect of a novel CO₂ packaging method in combination with organic acids on the microbial growth in fresh pork meat. Fresh pork fillet was packed with a small amount of 100% CO₂ (initial gas/product ratio 0.2/1.0) and a brine solution containing citric acid (3% w/w, pH 5), acetic acid (1% w/w, pH 5) or a combination of both. Microbial counts and composition in the product were determined. CO₂, citric acid and acetic acid each reduced total growth after four weeks of storage and delayed the onset of microbial growth. Combinations of treatments increased the effects and microbial growth in samples packed with a combination of CO₂ and both acids was negligible even after 35 days. However, the addition of citric acid to the packages led to significant precipitation in the brine. Analysis of the bacterial flora showed that lactic-acid bacteria dominated the flora in samples packed with CO₂ while vacuum-packed samples contained high numbers of Pseudomonas sp. and yeast. As all CO₂ dissolved in the product within hours after packaging, the outer appearance of the package was that of a vacuum-package. As a result, this novel packaging method combined the advantages of modified atmosphere packaging (antimicrobial effect of CO₂) and vacuum packaging (low space requirement).     

Effect of dietary humate on the pH,TBARS and microbiological properties of vacuum‐ and aerobic‐packed breast and drumstick meats of broilers

The current trial determined the influence of dietary humate, including humic, fulvic and ulmic acids and some microminerals on the pH, TBARS and microbiological properties of vacuum‐packed and aerobic‐packed breast fillets and drumsticks of broilers. A total of 240 male broiler chicks (Ross‐308) were randomly allocated into four dietary treatments (H₀, H₁, H₂ and H₃ groups). A basal diet (H₀), basal diet plus 0.1 (H₁), 0.2 (H₂) and 0.3% (H₃) humate (Farmagulator DRY^?, Humate, Farmavet International Inc, Kocaeli 41 400, Turkey) were offered during the experimental feeding period. At the end of the trial all chicks were slaughtered. After standard dissection of carcasses, the breasts and drumsticks were divided into two groups for vacuum packaging or aerobic packaging. Packed breasts and drumsticks were stored at 3 °C for 12 days. The breasts and drumsticks were analyzed for pH, TBARS, total mesophilic, total psychrotrophic, lactic acid bacteria and Enterobacteriacea counts at 0, 2, 4, 6, 8, 10 and 12 days of storage. The feeding of humate decreased pH values of breast fillets and drumstick muscles (p < 0.01), especially at the 0.1% level. The TBARS value decreased (p < 0.01) when compared with the without‐humate group (H₀). Total aerobic mesophilic (p < 0.01), total aerobic psychrotrophic (p < 0.01) and lactic acid bacteria (p < 0.05) counts were lower in the H₃ group than the other groups. The effect of meat type on pH, TBARS, total aerobic mesophilic (p < 0.01) and lactic acid bacteria (p < 0.05) and Enterobacteriacea counts was significant. While the pH and TBARS values of breast fillets were lower than those of drumstick meats, the total mesophilic, total psychrotrophic, lactic acid bacteria and Enterobacteriacea counts of drumstick meats were higher than those of breast fillets. The effect of packaging type on pH (p < 0.01), TBARS (p < 0.01), total aerobic psychrotrophic bacteria (p < 0.01) and Enterobacteriacea counts (p < 0.01) was found statistically significant and the maximum values were determined in the aerobic‐packed samples. In addition, investigated parameters were also affected by storage period. While the total aerobic mesophilic count decreased, the other parameters increased when compared with zero day of storage. Copyright © 2005 Society of Chemical Industry     

Microbiological characteristics of poultry patties in relation to packaging atmospheres

Microbial characteristics under different atmospheres (vacuum, air, MAP₁: 80% O₂/20% CO₂ and MAP₂: 5% O₂/65% N₂/30% CO₂) of poultry patties made of a mixture of ostrich, chicken and turkey meat were evaluated. The meat preparations were examined for changes in pH, colour properties (CIE L*, a*, b*), headspace composition, and bacterial counts (total viable cell, psychrotrophs, Enterobacteriaceae, lactic acid bacteria, Staphylococcus spp., Brochothrix thermosphacta, Pseudomonas spp.). The use of a high O₂ atmosphere (MAP₁) quickly leads to a loss of the appealing red colour. A limited alteration occurred with use of MAP₂ and vacuum. For total viable counts a cell load higher than 8 log cfu g^?1 for the samples packaged in air, MAP₁ and MAP₂ at the end of storage was observed. Whereas, for the vacuum packed samples the cell load never reached values higher than 8 log cfu g^?1. Enterobacteriaceae, B. thermosphacta and Pseudomonas spp. cell load was less with the vacuum (7.60, 5.06 and 7.17 log cfu g^?1, respectively) and MAP₂ packaging (7.08, 5.60 and 7.40 log cfu g^?1, respectively). However, the high microbial loads suggest that an improvement of the microbiological quality of poultry meat is necessary if the producers are going to propose this new meat preparation on the market.     

Effect of different packing treatments on the microbiological and physicochemical characteristics of untreated green olives of the Conservolea cultivar

Microbiological, physicochemical and organoleptic changes were studied in non‐pasteurised samples of untreated green olives cv Conservolea stored at 20 °C for 180 days under different preservation treatments (acidified brine and modified atmospheres). The microbial flora consisted of lactic acid bacteria and yeasts, while no enterobacteria and pseudomonads were enumerated in any package. Although no thermal treatment was applied to the packages, no sediment formation was observed due to the growth of propionic bacteria. Olives packed in brine supplemented with 0.3% lactic and 0.3% citric acids presented the highest acidity, the lowest brine and flesh pH and the lowest dark brine colour as measured by the parameter A₄₄₀?A₇₀₀. Olives packed in modified atmospheres (vacuum, 40% CO₂/30% O₂/30% N₂ and air) presented a progressive loss of fruit firmness and colour with time. At the end of the storage period, olives packed in aerobic conditions and 40% CO₂/30% O₂/30% N₂ presented the lowest firmness and skin colour and were unacceptable to the panellists. The best quality characteristics were maintained in vacuum‐packed olives, as indicated by the higher organoleptic scores. Firmness degradation followed first‐order kinetics (r² > 0.980) and the expected shelf‐life was 23, 15 and 9 months for olives packed in vacuum, 40% CO₂/30% O₂/30% N₂ and air respectively. Copyright © 2004 Society of Chemical Industry     

Effect of modified atmosphere and vacuum packaging on some quality characteristics and the shelf-life of “morcilla”, a typical cooked blood sausage

The effect of modified atmosphere and vacuum packaging on the shelf-life of “morcilla”, a traditional cooked blood sausage, was investigated. A total of 99 “morcillas” were packaged under vacuum and in modified atmosphere using three different gas mixtures: 15:35:50/O₂:N₂:CO₂ (atmosphere 1), 60:40/N₂:CO₂ (atmosphere 2) and 40:60/N₂:CO₂ (atmosphere 3), and stored during 2, 4, 6 and 8 weeks at 4 °C. Shelf life evaluation was based on pH, water activity (a_w), colour (CIE L*, a*, b*, C* and h*), TBARS formation and microbial counts. The results indicated that, in general, storage time affected (P < 0.05) all parameters whereas no significant differences were observed (P > 0.05) among packaging conditions. Based on the microbial counts, the shelf-life of “morcilla” would be greater than 8 weeks for all packaging conditions. Samples packaged with high CO₂ concentrations (40:60/N₂:CO₂) showed the lowest values of TBARS at the end of storage.     

Evaluation of modified casings and chitosan‐PVA packaging on the physicochemical properties of cooked Sichuan sausages during long‐term storage

The effects of a modified casing and chitosan‐poly‐vinyl alcohol antimicrobial packaging (CP packaging) on sausage colour, texture, microbial spoilage and volatile compounds after 29‐days storage were investigated. Casings were modified by surfactant solution (composed of soy lecithin and soy oil) and lactic acid. For samples stored in CP packaging, there were no significant differences between day 1 and day 29 in relation to sausage hardness and springiness (P > 0.05). Redness increased over storage time regardless of treatments and packagings. Total plate counts of samples packaged by CP packaging were lower than 1 log cfu g^?1 during 29‐days storage. Cyclohexene, 1‐methyl‐4‐(1‐methylethylidene)‐ and α‐copaene were found in samples with control casings and CP packaging after 15‐days storage. The improved characteristics of the natural casing will enable meat processors or manufactures to enhance sausage production with a low sausage burst incidence, while the CP packaging will inhibit the intensive microbial growth.     

Shelf life of fresh foal meat under MAP, overwrap and vacuum packaging conditions

The objective of this study was to investigate the physico-chemical properties, the microbial counts and the sensory properties' changes of foal steaks packed under various conditions. The experimental packaging systems were: (i) vacuum packaging (VP), (ii) overwrap packaging and (iii) two modified atmosphere packaging methods (MAP): high O(2) MAP (80% O(2)+20% CO(2)) and low O(2) MAP (30% O(2)+70% CO(2)). The meat was stored at 2°C during 14days and tested for pH, colour, lipid and protein oxidation, microbial counts and sensory assessment of odour, colour and appearance. Of the two MAP, overwrap and VP, both MAP were the most effective treatments for the inhibition of the total viable counts (TVC), Pseudomonas spp., psychrotrophic aerobic bacteria, lactic acid bacteria, Enterobacteriaceae as well as moulds and yeast. According to the sensory evaluation, foal steaks packed under overwrap and MAP treatments resulted unacceptable after 7days of storage, whereas the vacuum-packed meat was still acceptable. Moreover, the redness value decreased significantly (P<0.001) with all treatments during the storage time, except for the vacuum packs, which increased significantly (P<0.001). Finally, foal steaks from overwrap packaging and MAP conditions had a greater increase of TBAR'S values and carbonyl content during the storage time. High O(2) levels affected foal meat quality negatively, while anaerobic conditions extended the meat's shelf life up to 14days.     

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.     

Colour of hot paprika from the La Vera and Murcia regions packaged in different atmospheres during storage

This study compared the behaviour of hot paprika (Capsicum annuum L.) samples from the district of La Vera and the region of Murcia packaged in five different conditions during storage. The following five different packaging conditions were used in this study: modified atmosphere packaging with three different conditions (100% N₂; 50% N₂ and 50% CO₂; and 100% CO₂), vacuum packaging and traditional packaging (product packaging system without modifying the atmosphere). After the samples were packaged, they were stored for 8 months at room temperature (normal storage conditions). The following parameters were used to indicate the quality of the samples: Aw, ASTA colour, CIE_L*a*b* colour parameters, and the composition of red and yellow compounds. The results indicate that the modified atmosphere packaging and vacuum packaging exerted a protective effect on the paprika quality characteristics regardless of the paprika origin. However, no clear differences were detected between the effect of vacuum packaging and the different modified atmosphere packaging conditions.