Effects of high-pressure treatment on the microflora of oysters (Crassostrea gigas) during chilled storage

The microbiological quality of oysters high-pressure (HP)-treated in-shell at 260 MPa for 3 min, or 500 or 800 MPa for 5 min and then stored at 2 °C, were investigated. Microbial counts after HP treatment showed that the bacterial load was reduced after treatment at all pressures to levels below the detection limit. Randomly-selected isolates from the total aerobic viable counts of untreated and HP-treated oysters after 14 days of storage were identified by the API identification system. Bacteria isolated from oysters HP-treated at 260 MPa were Shewanella putrifaciens and Pseudomonas fluorescens. For oysters HP-treated at 500 or 800 MPa, the main bacteria isolated were Pseudomonas spp. Vibrio spp. comprised 44% of the microflora in untreated oysters after storage for 14 days at 2 °C, but no Vibrio were detected in HP-treated oysters. This study confirmed that HP processing can inactivate microorganisms and delay microbial growth in chilled stored oysters.

Industrial relevance

High-pressure (HP) treatment is being increasingly employed for commercial processing of oysters but no studies of the microflora of HP-treated in-shell oysters have been reported. HP treatment significantly changed the microflora of oysters and apparently has good potential for inactivation of Vibrio spp as HP treatment, in combination with adequate chilled storage, can improve the microbiological shelf-life and safety of oysters.     

Effect of sulphur dioxide on microbial growth in refrigerated pre-peeled potatoes packaged in plastic films

Microbial growth in pre-peeled potatoes was analysed to determine the simultaneous effect of sodium bisulphite concentration (105–219 mg kg^?1), storage temperature (4, 7 and 10°C) and gaseous permeability of the packaging plastic film (polyethylene and EVA—SARAN—EVA used in vacuum) on product storage life. Composition of the microbial flora was determined at the beginning and the end of the storage period, and the principal microorganisms causing spoilage of the product were observed to be Pseudomonas spp and Enterobacteriaceae. Lag phase duration and specific rate constants were determined for these microorganisms in samples stored at each condition. In polyethylene-packaged samples microbial growth was observed at various temperatures and SO₂ concentrations were tested. With vacuum packaging in low oxygen permeability films and residues of 100 mg SO₂ kg^?1, microbial counts were maintained in the lag phase; larger residues produced microbial inhibition at 4, 7 and 10°C.     

Properties of starches separated from potatoes stored under different conditions

Starches from 11 potato cultivars stored at five temperatures (4, 8, 12, 16 and 20 °C) for 120 days were evaluated for physicochemical, thermal and pasting properties. Amylose content and swelling power increased with increase in storage temperatures. The proportion of small size granules was higher in starches from potatoes stored at 4 °C. The starch granules of stored potatoes were slightly rough-surfaced and pitted; the effect was pronounced in those stored at 4 °C. Starches from potatoes stored at 4 °C showed lower onset gelatinization temperature and conclusion temperature than did starches from potatoes stored between 8 and 20 °C. Starches from potatoes stored at higher temperature (20 °C) showed higher peak viscosity, set back, as well as gel hardness, chewiness and gumminess than did starches from those stored between 4 and 16 °C. Amylose content showed significant positive correlation with gumminess and setback while swelling power showed significant positive correlation with peak viscosity and hot-paste viscosity.     

Effects of modified atmosphere and vacuum packaging on the growth of spoilage and inoculated pathogenic bacteria on fresh poultry

Fresh chicken breast meats inoculated withYersinia enterocolitica andAeromonas hydrophila were packaged in glass jars either containing different compositions of modified atmospheres (MA) (100% CO₂; 80% CO₂/20% N₂), or in vacuo or containing air, and were stored at 3±1°C and 8±1°C. The changes in gas composition as well asY. enterocolitica, A. hydrophila, total aerobic bacterial, total psychrotrophic, Lactobacilli and Enterobacteriaceae counts were determined after 0,1,3,7,9,11 and 14 days of storage. The results show that while the growth ofY. enterocolitica andA. hydrophila were retarded following MA storage, the pathogens were capable of growth in MA and vacuum storage at both temperatures, for the inoculation levels studied. For total aerobic bacterial counts, there were no differences between the values for chicken breast meats kept in different atmospheres. Being packaged in CO₂ had the greatest inhibitory effect on the growth of psychrotrophic aerobic bacteria during the first 3 days. Lactic acid bacteria levels of samples stored in MA conditions and in vacuo increased rapidly when compared to those levels of samples stored in air. It was also found that the effect of MA storage increased at 3±1°C.     

Incidence, radioresistance, and behavior of Psychrobacter spp. in rabbit meat

The relative incidence of Psychrobacter spp. in rabbit meat, the radioresistance of these bacteria, and the growth of nonirradiated and irradiated psychrobacter isolates, alone and in coculture, during chilled storage of inoculated sterile rabbit meat was investigated. Psychrobacter spp. accounted for 4.2% of the storage psychrotrophic flora of 30 rabbit carcasses. The radiation D10-values of 10 Psychrobacter isolates, irradiated at 4 degrees C in minced rabbit meat, ranged from 0.8 to 2.0 kGy, with significant (P < 0.05) differences among strains. Over 12 days of storage at 4 degrees C, pure cultures of two nonirradiated psychrobacter strains (D10 = 2 kGy) were capable of substantial increases (up to 3 log CFU/g) in sterile rabbit meat, but when the fastest growing strain was cocultured with Pseudomonas fluorescens and Brochothrix thermosphacta isolates, maximum cell densities and growth rates were significantly (P < 0.01) lower. After irradiation (2.5 kGy) of pure cultures in sterile rabbit meat, surviving cells of both Psychrobacter strains decreased for a period of 5 to 7 days and then resumed multiplication that, at day 12, resulted in a similar increase (1.6 to 1.7 log CFU/g) over initial survivor numbers. When irradiated in combination with the spoilage bacteria, one of the strains required 12 days to reach initial numbers. In conclusion, Psychrobacter spp. are radioresistant nonsporeforming bacteria with a low relative incidence among the storage flora of rabbit meat, unable to compete with food spoilage bacteria in this ecosystem and apparently not a major contributor to the spoilage of rabbit meat after irradiation.     

Storage Stability of Intermediate Moisture Mullet Roe

A storage stability study was performed on intermediate moisture roe (a_w= 0.84, salt content = 4%). Samples were stored at various temperatures for up to 1 month. Microbial analyses indicated that bacteria could grow from 5–25°C. Fungi grew at 15° and 25°C while their growth was inhibited at 5°C; however, a lag phase was detected at 15°C. TBA values increased linearly during storage. Microbial analyses, chemical determination of rancidity and sensory evaluations showed that the product was still acceptable after 30 days storage at 5°, 15° or 25°C.     

Alterations of the phylloepiphytic bacterial community associated with interactions of Escherichia coli O157:H7 during storage of packaged spinach at refrigeration temperatures

This study investigated the effects of packaging and storage temperature on the spinach phylloepiphytic bacterial community and fate of Escherichia coli O157:H7. Freshly harvested spinach was rinsed and/or disinfected, packaged and stored under typical retail conditions (4 °C) or under temperature abuse conditions (10 °C) for a period of 15 days. The final population size of culturable epiphytic bacteria after 15 days of storage was not affected by the temperature of storage or the presence of E. coli O157:H7. However, analysis of the bacterial community using denaturing gradient gel electrophoresis of 16s rDNA revealed changes with time of storage and the presence of E. coli O157:H7. Excision and sequencing of prominent DGGE bands identified that the majority of sequences belonged to the phyla Actinobacteria, Bacteroidetes, Firmicutes and Alphaprotebacteria. After 10 days of storage at 4 °C or 10 °C the population became more dominated by psychrotrophic bacteria. Removal of the epiphytic bacteria resulted in significant increases in numbers of E coli O157:H7 at 10 °C and was associated with decreased expression of E. coli O157:H7 virulence (stxA, curli, eaeA) and stress response (rpoS, sodB) genes. In conclusion, storage temperature and time of storage of packaged spinach affected the diversity of the epiphytic spinach microbiota which influenced the growth, establishment, physiology and potentially virulence of E. coli O157:H7.     

Microbiological, Chemical and Sensory Properties of Pre-cooked Roast Beef Preserved with Horseradish Essential Oil

Pre-cooked roast beef slices were stored 28 days at 4±2°C in air or 100% N₂ with and without vaporized horseradish essential oil (HEO). Addition of 20 μL HEO/L restricted growth of most spoilage bacteria. Pseudomonas spp. and Enterobacte-riaceae were strongly inhibited by HEO. Lactic acid bacteria were more resistant to the antimicrobial effect and dominated spoilage flora. Sensory evaluation and headspace analysis by gas chromatography/mass spectrometry revealed that development of off-flavors and odors derived from fat oxidation products was delayed by HEO. Cooked meat color was also preserved in samples stored under HEO.     

Technology-induced selection towards the spoilage microbiota of artisan-type cooked ham packed under modified atmosphere

The microbiota associated with a highly-perishable Belgian artisan-type cooked ham was analyzed through plating and (GTG)₅-fingerprinting of isolates throughout its processing chain. The raw tumbled meat was characterized by the presence of a versatile microbiota around 4.8 log(cfu g⁻¹), consisting of lactic acid bacteria, staphylococci, Brochothrix thermosphacta, Gram-negative bacteria, and yeasts. Pasteurisation of the ham logs reduced bacterial counts below 2 log(cfu g⁻¹) and subsequent manipulations selected for leuconostocs and carnobacteria. Also, B. thermosphacta and several Enterobacteriaceae were found at this stage. During storage in an intermediate high-care area for 2 days, a selection towards certain Enterobacteriaceae (Hafnia alvei, Enterobacter spp., and Pantoea agglomerans) and lactic acid bacteria (mainly vagococci and Streptococcus parauberis) was observed. B. thermosphacta, Leuconostoc carnosum and carnobacteria were also detected, but only after allowing bacterial outgrowth by incubating the meat logs at 7 °C for four weeks. After a mild post-pasteurisation process and subsequent handling, incubation of the meat logs at 7 °C for four weeks led to outgrowth of Enterobacteriaceae (mainly Enterobacter spp. and Serratia spp.). B. thermosphacta, and lactic acid bacteria (Enterococcus faecalis, Leuc. carnosum, and Carnobacterium maltaromaticum) were also found. After slicing and packaging under modified atmosphere, the microbiota of the refrigerated end-product consisted of leuconostocs, carnobacteria, and B. thermosphacta.     

Microbial background flora in small-scale cheese production facilities does not inhibit growth and surface attachment of Listeria monocytogenes

The background microbiota of 5 Norwegian small-scale cheese production sites was examined and the effect of the isolated strains on the growth and survival of Listeria monocytogenes was investigated. Samples were taken from the air, food contact surfaces (storage surfaces, cheese molds, and brine) and noncontact surfaces (floor, drains, and doors) and all isolates were identified by sequencing and morphology (mold). A total of 1,314 isolates were identified and found to belong to 55 bacterial genera, 1 species of yeast, and 6 species of mold. Lactococcus spp. (all of which were Lactococcus lactis), Staphylococcus spp., Microbacterium spp., and Psychrobacter sp. were isolated from all 5 sites and Rhodococcus spp. and Chryseobacterium spp. from 4 sites. Thirty-two genera were only found in 1 out of 5 facilities each. Great variations were observed in the microbial background flora both between the 5 producers, and also within the various production sites. The greatest diversity of bacteria was found in drains and on rubber seals of doors. The flora on cheese storage shelves and in salt brines was less varied. A total of 62 bacterial isolates and 1 yeast isolate were tested for antilisterial activity in an overlay assay and a spot-on-lawn assay, but none showed significant inhibitory effects. Listeria monocytogenes was also co-cultured on ceramic tiles with bacteria dominating in the cheese production plants: Lactococcus lactis, Pseudomonas putida, Staphylococcus equorum, Rhodococcus spp., or Psychrobacter spp. None of the tested isolates altered the survival of L. monocytogenes on ceramic tiles. The conclusion of the study was that no common background flora exists in cheese production environments. None of the tested isolates inhibited the growth of L. monocytogenes. Hence, this study does not support the hypothesis that the natural background flora in cheese production environments inhibits the growth or survival of L. monocytogenes.     

Use of eye fluid refractive index in sardine (<Emphasis Type="Italic">Sardina pilchardus</Emphasis>) as a freshness indicator

In this study the usage of eye fluid refractive index as a freshness indicator for sardine (Sardina pilchardus) was investigated. Eye fluid refractive index measurements and quality control analyses of sardine during storage at 0°C and +4°C were performed at 24h intervals. According to the sensory analysis results, the sardines stored at 0°C and +4°C had a shelf life of 6 and 4days, respectively. The changes in eye fluid refractive index values during storage at 0°C were not significant while the changes at +4°C were significant (p<0.01). TVB-N and TMA-N values significantly (p<0.01) increased. No microbiological growth was observed at 0°C, however the increase in microorganism counts was significant at +4°C. As a result, eye fluid refractive index measurements can be used as a quality criterion for sardine freshness, when stored at +4°C.     

A comparative study of changes in the microbiota of apple juice treated by high hydrostatic pressure (HHP) or high pressure homogenisation (HPH)

The objective of this study was to assess the effect of High Pressure Homogenisation (HPH) compared with High Hydrostatic Pressure (HHP) on the microbiological quality of raw apple juice during storage at ideal (4 °C) and abuse (12 °C) temperatures. In the case of HPH, only low numbers of micro-organisms were detected after treatment at 300 MPa (typically between 2 and 3 log.ml⁻¹). These were identified as Streptomyces spp., and numbers did not increase during storage of the juice for 35 days, irrespective of storage temperature. In the case of HHP, the total aerobic counts were also reduced significantly (p < 0.05) after treatment for 1 min at 500 and 600 MPa and the numbers did not increase significantly during storage at 4 °C. However, during storage at 12 °C the counts did increase significantly (p < 0.05) and by day 14 counts at 500 MPa were not significantly different from the control juice. This confirms that good temperature control is important if the full benefits of HHP treatment are to be realised.Frateuria aurantia dominated the microbiota of the HHP apple juice stored at 12 °C along with low levels of Bacillus and Streptomyces spp.The HPH and HHP juices both turned brown during storage indicating that neither treatment was sufficient to inactivate polyphenol oxidase. The enzyme is known to be pressure resistant and this discolouration was controlled by a heat treatment (70 °C for 1 min) used in commercial practice and given prior to HP treatment.     

MICROBIAL PROLIFERATION AND MATHEMATICAL INDICES OF VACUUM-PACKED BOVINE MEAT

Microbial proliferation on red meat carcasses stored at low temperatures is known to occur, and this proliferation is to a large extent dependent on the types of organisms present as well as on the initial microbial concentration. In this study, the microbial shelf life of vacuum‐packed bovine meat stored at 5 and 18C was investigated, and mathematical indices were generated. This was carried out to investigate the proliferation of the various microbiota at initial storage temperatures as well as to simulate conditions where a breach in the cold chain might occur. Throughout the 5C storage period, the numbers of Enterococcus spp. and Proteus spp. decreased, whereas those of the remaining microorganisms studied increased at a relatively slow pace. Lactose‐fermenting Enterobacteriaceae, Pseudomonas aeruginosa, Enterococcus spp. and total coliform counts decreased after 10 days of incubation at 18C. In addition, Shigella spp. was also detected after a prolonged period of storage at high storage temperature. Strong positive correlations were noted between several genera at both storage temperatures. Mathematical indices were also generated to circumvent any hazardous risks associated with vacuum‐packed bovine meat spoilage in the future. The results show that at these two temperatures, the various genera reacted totally differently with specific hazards originating from the predominance of certain groups. The initial microbial load played a pivotal role in the patterns of growth at both 5 and 18C.     

Modeling the Growth of Epiphytic Bacteria on Kale Treated by Thermosonication Combined with Slightly Acidic Electrolyzed Water and Stored under Dynamic Temperature Conditions

The growth of epiphytic bacteria (aerobic mesophilic bacteria or Pseudomonas spp.) on kale was modeled isothermally and validated under dynamic storage temperatures. Each bacterial count on kale stored at isothermal conditions (4 to 25 °C) was recorded. The results show that maximum growth rate (μ_max) of both epiphytic bacteria increased and lag time (λ) decreased with increasing temperature (P < 0.05). The maximum population density (N_max) of Pseudomonas spp. was significantly greater than that of aerobic mesophilic bacteria, particularly in treated samples and/or at 4 and 10 °C (P < 0.05). The relationship between μ_max of both epiphytic bacteria and temperature was linear (R² > 0.97), whereas lower R² > 0.86 and R² > 0.87 was observed for the λ and N_max, respectively. The overall predictions of both epiphytic bacterial growths under nonisothermal conditions with temperature abuse of 15 °C agreed with the observed data, whereas those with temperature abuse of 25 °C were greatly overestimated. The appropriate parameter q₀ (physiological state of cells), therefore, was adjusted by a trial and error to fit the model. This study demonstrates that the developed model was able to predict accurately epiphytic bacterial growth on kale stored under nonisothermal conditions particularly those with low temperature abuse of 15 °C.     

Identification of bacteria crucial to histamine accumulation in pacific mackerel during storage

Bacterial growth and histamine formation in Pacific mackerel during storage at 0, 4, 15, and 25 degrees C were monitored. To identify bacterial species contributing to histamine formation, several groups of bacteria were isolated by using selective media under temperatures corresponding to the various storage conditions. Initially, low counts of bacteria were found in the gill, skin, and intestine of fresh fish, and only weak histamine formers were found in the gill. Histamine was found in the muscle when fish were stored above 4 degrees C, and aerobic plate counts reached 10(6) CFU/g. When fish became unsuitable for human consumption by abusive storage, toxicological levels of histamine were always found. The highest level of histamine formed was 283 mg/100 g in 2 days. The optimum temperature for supporting growth of prolific histamine formers was 25 degrees C. The most prolific and prevalent histamine former was Morganella morganii, followed by Proteus vulgaris, both of which were isolated on violet red bile glucose (VRBG) agar. At 15 degrees C, a significant level of histamine was still produced in fish muscle, although prolific histamine formers were less frequently detected than at 25 degrees C. The isolates on thiosulfate citrate bile salts sucrose (TCBS) agar were weak histamine formers and identified as Vibrio parahaemolyticus and Vibrio alginolyticus. At 4 degrees C, less than 57.4 mg/100 g of histamine was found in fish stored for 14 days. Most isolates were natural bacterial flora in the marine environment and identified as weak histamine formers. At 0 degrees C, neither histamine former nor histamine production was detected up to 14 days of storage.     

Modelling the relation between bacterial growth and storage temperature in pasteurized milks of varying hygienic quality

The shelf-life of pasteurized milk was mainly determined by the level of contamination with Gram-negative psychrotrophic bacteria. The length of lag phase of the bacteria was also important, although the generation times of the naturally contaminating flora seemed to be of little relevance except for milks where the shelf-life exceeded 10 days at 6°C. The effect of temperature on growth of the contaminants could be accurately determined by the 'square root' plot but the conceptual minimum temperature for growth (T_o) varied. The variation was related to the quality of the pasteurized milk. Effects of temperature on generation time, length of lag phase and shelf-life were most marked at temperatures below 15°C.
The microflora of pasteurized milk varied significantly with storage temperature. At refrigeration temperatures, spoilage was mainly due to the growth of Pseudomonas spp. Enterobacteriaceae and Gram-positive bacteria assumed greater importance in the spoilage of milks stored at temperatures above 10°C. Milks of good quality also contained Bacillus spp and this group of bacteria were not detectable in milks with short shelf-lives.     

Tracking spoilage bacteria in commercial poultry processing and refrigerated storage of poultry carcasses

Four trials were conducted to examine the effect of commercial processing and refrigerated storage on spoilage bacteria in the native microflora of broiler carcasses. Prescalded, picked, eviscerated, and chilled carcasses were obtained from a commercial processing facility, and psychrotrophs in the bacterial flora were enumerated on Iron Agar, Pseudomonas Agar, and STAA Agar. The size of the population of spoilage bacteria on processed carcasses stored at 4 degrees C for 7, 10, or 14 days was also determined. Bacterial isolates were identified and dendrograms of the fatty acid profiles of the isolates were prepared to determine the degree of relatedness of the isolates. Findings indicated that although some processing steps increased the level of carcass contamination by selected bacteria, the number of spoilage bacteria recovered from processed carcasses was significantly (P< or = 0.05) less than the number of bacteria recovered from carcasses entering the processing line. Acinetobacter and Aeromonas spp. were the primary isolates recovered from carcasses taken from the processing line. During refrigerated storage, there was a significant (P < or =0.05) increase in the population of bacteria on the carcasses, and Pseudomonas spp. were the predominant bacteria recovered from these carcasses. Dendrograms of the fatty acid profiles of the isolates indicated that bacterial cross-contamination of carcasses occurs during all stages of processing and that some bacteria can survive processing and proliferate on carcasses during refrigerated storage. Furthermore, cross-contamination was detected between carcasses processed on different days at the same facility. Findings indicate that although poultry processing decreases carcass contamination by psychrotrophic spoilage bacteria, significant levels of bacterial cross-contamination occur during processing, and bacteria that survive processing may multiply on the carcasses during refrigerated storage.     

Effects of packaging type and storage temperature on the growth of foodborne pathogens on shredded ‘Romaine’ lettuce

Fresh produce can be a vehicle for the transmission of pathogens capable of causing human illnesses and some of them can grow on fresh-cut vegetables. The survival and growth of Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes inoculated onto shredded lettuce was determined under modified atmosphere packaging conditions, at various storage temperatures. We also monitored changes in pH and gas atmospheres within the packages and the growth of psychrotrophic and mesophilic microorganisms. After pathogen inoculation, shredded lettuce was packaged in films of different permeability and stored at 5 and 25 °C. After 10 days at 5 °C populations of E. coli O157:H7 and Salmonella decreased approximately 1.00 log unit while L. monocytogenes increased about 1.00 log unit, in all package films. Moreover, the pathogens level increased between 2.44 and 4.19 log units after 3 days at 25 °C. Psychrotrophic and mesophilic bacteria had similar growth at both temperatures with higher populations in air than in the other atmospheres. The composition of the storage atmosphere within the packaging of lettuce had no significant effect on the survival and growth of the pathogens used in this study at refrigeration temperatures. The results obtained can be considered as a warning indicator, which reinforces the necessity for corrective measures to avoid contamination of vegetables.     

Biogenic amine changes in barramundi (Lates calcarifer) slices stored at 0 °C and 4 °C

The biogenic amines formation in barramundi (Lates calcarifer) slices kept for 15 days at 0 °C and 4 °C were investigated using nine biogenic amines, total plate counts and biogenic amines formers. Significant differences in biogenic amines concentrations of barramundi slices stored at 4 °C and at 0 °C after 3 days of storage were observed. All amines, except tryptamine, 2-phenylethylamine, tyramine and agmatine in the slices increased with time during storage at both temperatures. At the end of the storage period, histamine concentrations were 82 mg/kg and 275 mg/kg for samples kept at 0 °C and 4 °C, respectively. At day 15, the total plate count was approximately 8.6 log CFU/g for sample kept at 0 °C and 9.7 log CFU/g for samples kept at 4 °C. Histamine-forming bacteria (HFB) in all samples ranged from 5.4 to 6.1 log CFU/g at 0 °C and 4 °C, respectively. The observed shelf-life of barramundi slices were 6–9 days.     

Physicochemical and microbiological changes of “Souvlaki” – A Greek delicacy lamb meat product: Evaluation of shelf-life using microbial,colour and lipid oxidation parameters

Fresh Souvlaki-type lamb meat was packaged under vacuum (VP) and modified atmospheres (MAs) and stored under refrigeration (4 °C) for a period of 13 days. The following gas mixtures were used: M1: 30%/70% (CO₂/N₂) and M2: 70%/30% (CO₂/N₂). Identical samples were aerobically-packaged and used as control samples. Quality evaluation of product stored under the above packaging conditions was conducted using physicochemical and microbiological analyses. Of the chemical parameters determined, pH values of product showed no significant differences for all packaging treatments as a function of storage time. Lipid oxidation of lamb meat was enhanced by aerobic storage and gas mixture M1, whereas VP and gas mixture M2 controlled lipid oxidation to a greater extent. Souvlaki colour stability (as determined by a^∗, b^∗ and L^∗ values) was not negatively affected by either VP or MA conditions during the 13 days of storage. Of the two MAs and VP used, gas mixture M2 and VP were the most effective treatments for the inhibition of total viable counts (TVC), Pseudomonas spp., yeasts and Brochothrix thermosphacta in Souvlaki meat. Lactic acid bacteria (LAB) and Enterobacteriaceae were also found in the microbial flora of Souvlaki and increased during storage under all packaging conditions used. Based on microbiological analysis data and on the proposed a^∗ values, the use of VP and MAP (M2: 70%CO₂/30N₂) extended the shelf-life of “Souvlaki” meat stored at 4 °C by approximately 4–5 days compared to aerobic packaging.