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.     

Effects of novel modified atmosphere packaging on lipid quality and stability of sardine (Sardina pilchardus) fillets

Modified atmosphere packaging (MAP) is an efficient method to increase shelf-life of fishery products by inhibiting bacterial growth and oxidative reactions. Beside the traditional gases used for MAP, novel gases such as argon (Ar) and nitrous oxide (N₂O) were approved for food use in the European Union. The present research investigates the effect of MAP with unconventional gas mixtures, that previously positively affected microbial shelf-life, on colour, lipid oxidation and sensorial characteristics of sardine fillets during storage. Four atmosphere conditions were tested: Air (20.8% O₂/79.2% N₂), N₂ (30% CO₂/70% N₂), N₂O (30% CO₂/70% N₂O) and Ar (30% CO₂/70% Ar). Samples were stored for 12 days at 3 °C. Results showed that the removal of oxygen significantly inhibited the oxidation process; however, most of the investigated parameters related to fat oxidation did not show any improvement, except for a slight decrease in lipid hydrolysis and improvement in sensory properties in the packaging containing Ar.     

Effect of Modified Atmosphere Packaging on Shelf-Life of Iced Fresh Hake Slices

Shelf-life of hake slices (Merluccius merluccius) stored in the ice state (2±1°C) under modified atmosphere packaging (MAP) conditions was determined by measurements of pH, total volatile bases (TVB) and trimethylamine (TMA) content, mesophilic and psychrophilic bacterial counts, malonaldehyde content, exudation, protein functionality and sensorial analyses (colour and odour). The effect of different gas mixtures were evaluated: (1) 40% CO₂, 50% N₂, 10% O₂; (2) 60% CO₂, 30% N₂, 10% O₂; (3) 40% CO₂, 30% N₂, 30% O₂; (4) 60% CO₂, 10% N₂, 30% O₂ and (5) air (control). Important differences were found between MAP-stored and air-stored hake slices. Shelf-life of hake stored under MAP conditions was two-fold extended. Bacterial growth wasinhibited, increases of pH, TMA and TVB were reduced, and alterations inprotein functionality were delayed, and off-odours were not noted in MAP-stored hake slices after 21 days storage. Significant correlations were found between TMA content and total viable count (TVC), as well as between apparent viscosity and exudation. Hake slices could be stored in the ice state under MAP conditions for about three weeks without an important loss of quality. Fish freshness, handling practices and initial bacterial load have an important influence of shelf-life of hake.     

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.     

Maintenance of safety and quality of refrigerated ready-to-cook seasoned ground beef product (meatball) by combining gamma irradiation with modified atmosphere packaging

Abstract: Meatballs were prepared by mixing ground beef and spices and inoculated with E. coli O157:H7, L. monocytogenes, and S. enteritidis before packaged in modified atmosphere (3% O₂+ 50% CO₂+ 47% N₂) or aerobic conditions. The packaged samples were irradiated at 0.75, 1.5, and 3 kGy doses and stored at 4 °C for 21 d. Survival of the pathogens, total plate count, lipid oxidation, color change, and sensory quality were analyzed during storage. Irradiation at 3 kGy inactivated all the inoculated (approximately 10⁶ CFU/g) S. enteritidis and L. monocytogenes cells in the samples. The inoculated (approximately 10⁶ CFU/g) E. coli O157:H7 cells were totally inactivated by 1.5 kGy irradiation. D¹⁰‐values for E. coli O157:H7, S. enteritidis, and L. monocytogenes were 0.24, 0.43, and 0.41 kGy in MAP and 0.22, 0.39, and 0.39 kGy in aerobic packages, respectively. Irradiation at 1.5 and 3 kGy resulted in 0.13 and 0.36 mg MDA/kg increase in 2‐thiobarbituric acid‐reactive substances (TBARS) reaching 1.02 and 1.49 MDA/kg, respectively, on day 1. Irradiation also caused significant loss of color and sensory quality in aerobic packages. However, MAP effectively inhibited the irradiation‐induced quality degradations during 21‐d storage. Thus, combining irradiation (3 kGy) and MAP (3% O₂+ 50% CO₂+ 47% N₂) controlled the safety risk due to the potential pathogens and maintained qualities of meatballs during 21‐d refrigerated storage. Practical Application: Combined use of gamma irradiation and modified atmosphere packaging (MAP) can maintain quality and safety of seasoned ground beef (meatball). Seasoned ground beef can be irradiated at 3 kGy and packaged in MAP with 3% O₂+ 50% CO₂+ 47% N₂ gas mixture in a high barrier packaging materials. These treatments can significantly decrease risk due to potential pathogens including E. coli O157:H7, L. monocytogenes, and S. enteritidis in the product. The MAP would reduce the undesirable effects of irradiation on quality, and extend the shelf life of the product for up to 21 d at 3 °C.     

Microbiological,physical and chemical characteristics of freshwater prawns (Macrobrachium rosenbergii) in modified‐atmosphere packaging

This study evaluated the influence of packaging atmosphere (air versus 50% N₂/50% CO₂) on microbiological (mesophiles, psychrotrophs), physical (gas measurement) and chemical (pH, total volatile basic nitrogen [TVB‐N], NH₃, H₂S and biogenic amines) parameters in freshwater prawns during storage at 0 ± 1 °C for 240 h. To select the most appropriate packaging, 21 batches of each treatment were analysed. Both the packaging permeability and the combination of gases affected the shelf life, but the modified‐atmosphere packaging (MAP) was more efficient than air packaging, increasing the shelf life by 40 h. The parameters of pH and TVB‐N showed no statistical difference between the two atmosphere conditions all along the storage period. The biogenic amine agmatine showed potential for use as a quality indicator due to the increased concentration during storage. In further studies, this amine can be applied as an indicator for public health issue.     

Retail Shelf-Life of Pork Dipped in Organic Acid before Modified Atmosphere or Vacuum Packaging

Modified atmosphere packaging (MAP) is increasingly popular for meat, but raw, chilled pork in vacuum or anoxic environments has a purple color. The retail shelf‐life of pork chops dipped in 500 ppm ascorbic acid, 250 ppm citric acid, or no acid dip and stored at 1 °C before simulated retail display in MAP with gas exchange or air‐permeable packaging after vacuum pouch storage was determined. The 80% N₂:20% CO₂ in MAP was exchanged with 80% O₂:20% CO₂, and chops were removed from vacuum packages and overwrapped with permeable film (VP‐PVC) on the 7th day before simulated retail display at 4 °C. Shelf‐life traits were determined at 1, 7, 8, 10, 12, and 14 d postpackaging. The pH values changed with time, but returned to post‐dipped, prepackaged levels at the end of simulated retail storage. Weight loss of chops increased (P < 0.05) in VP‐PVC compared with MAP. The a* values increased (P < 0.05) and L* and b* values decreased during simulated retail display, with higher L*, a*, and b* color values for chops in MAP than VP‐PVC. Log numbers of psychrotrophic microorganisms were higher (P < 0.05) on VP‐PVC samples than for chops in MAP on days 12 and 14. Psychrotrophic counts on ascorbic acid‐treated samples were decreased compared with citric acid or no dipping on pork during simulated retail display. Pork chops in MAP with gas exchange had lighter and redder color, increased weight retention, decreased psychrotrophic counts, and increased lipid oxidation compared with conventional vacuum and overwrap packaging systems.     

Effect of muscle,ageing time and modified atmosphere packaging conditions on the colour,oxidative and microbiological stability of packed beef

The objective of this study was to evaluate the influence of two different vacuum ageing times (7 and 14 days) and the impact of the modified atmosphere packaging (MAP) configuration (gas/product ratios: 0.5 and 1 and gas composition: 70% O₂ + 30% CO₂ and 40% O₂ + 30% CO₂ + 30% N₂) on the quality of fresh beef during subsequent storage at 4 °C. For this purpose, three separate experiments were performed. For each experiment, two different muscles (Longissimus dorsi and Biceps femoris) were sampled from four double‐muscled Belgian Blue beef carcasses. Next to colour, also the evolution in microbial load, pH, O₂ and CO₂ in the headspace and lipid oxidation at the meat surface were evaluated. A vacuum ageing for 14 days compared with 7 days resulted in a higher initial microbial load on the day of MAP packaging, which resulted finally in a significantly shorter shelf life. This ageing effect was less pronounced on the colour stability and lipid oxidation of the meat samples. No significant influence of the packaging configuration on any of the analysed parameters (colour, microbial load, pH and lipid oxidation at the meat surface) was observed.     

臭氧水清洗结合气调包装对鲜切杭白菜保鲜效果的研究

以1.8mg/L臭氧水清洗的鲜切杭白菜为试验材料,研究不同气体组分的气调包装(CK为空气;A为5%O_2+5%CO_2+90%N_2;B为5%O_2+10%CO_2+85%N_2;C为10%O_2+5%CO_2+85%N_2;D为10%O_2+10%CO_2+80%N_2)对鲜切杭白菜保鲜效果的影响。结果表明:B组低氧高二氧化碳的包装能有效地抑制鲜切杭白菜上微生物的生长,保持其较好的感官品质,同时延缓VC、叶绿素及可溶性固形物含量的降低,防止杭白菜过快失水,有效地保证鲜切杭白菜的货架期在15d以上。     

Extending the shelf life of fresh ewe’s cheese by modified atmosphere packaging

This study evaluated the effect of modified atmosphere packaging (MAP) in extending the shelf life of a fresh ewe’s cheese stored at 4 °C for 21 days. Three batches were prepared with 20, 30 or 50% CO₂ with N₂ as filler gas. MAP controlled well the microbial growth, and the best result was obtained with 50% CO₂. Pathogens were not detected in any sample. Softening of cheese was best reduced by 30% or 50% CO₂. The sensory characteristics of the cheeses markedly decreased during storage. Only the sample stored with 50% CO₂ obtained an overall score above the acceptability at 14 days.     

Nondestructive and Continuous Monitoring of Oxygen Levels in Modified Atmosphere Packaged Ready‐to‐Eat Mixed Salad Products Using Optical Oxygen Sensors,and Its Effects on Sensory and Microbiological Counts during Storage

The objective of this study was to determine the percentage oxygen consumption of fresh, respiring ready‐to‐eat (RTE) mixed leaf salad products (Iceberg salad leaf, Caesar salad leaf, and Italian salad leaf). These were held under different modified atmosphere packaging (MAP) conditions (5% O₂, 5% CO₂, 90% N₂ (MAPC—commercial control), 21% O₂, 5% CO₂, 74% N₂ (MAP 1), 45% O₂, 5% CO₂, 50% N₂ (MAP 2), and 60% O₂, 5% CO₂, 35% N₂ (MAP 3)) and 4 °C for up to 10 d. The quality and shelf‐life stability of all packaged salad products were evaluated using sensory, physiochemical, and microbial assessment. Oxygen levels in all MAP packs were measured on each day of analysis using optical oxygen sensors allowing for nondestructive assessment of packs. Analysis showed that with the exception of control packs, oxygen levels for all MAP treatments decreased by approximately 10% after 7 d of storage. Oxygen levels in control packs were depleted after 7 d of storage. This appears to have had no detrimental effect on either the sensory quality or shelf‐life stability of any of the salad products investigated. Additionally, the presence of higher levels of oxygen in modified atmosphere packs did not significantly improve product quality or shelf‐life stability; however, these additional levels of oxygen were freely available to fresh respiring produce if required. This study shows that the application of optical sensors in MAP packs was successful in nondestructively monitoring oxygen level, or changes in oxygen level, during refrigerated storage of RTE salad products.     

Different MAP conditions to improve the shelf life of sea bass

Shelf life of cultured sea bass packaged in air, vacuum, and gas mixture packages stored for 40 days at 2.90±0.02°C was compared. The gas mixtures used contained CO₂, O₂, and N₂ at difference percentages (M1: 75% CO₂/25% N₂; M2: 60% CO₂/40% N₂; M3: 30% O₂/30% CO₂/40% N₂). Sensory and physical parameters, chemical changes, and microbiological counts were monitored during storage. Storage with a gas mix including 75 and 60% CO₂ was more effective than vacuum processing and packaging with a gas mix that included oxygen. Vacuum was the most effective method for preventing lipid oxidation. The optimum method for sea bass in view of all analysis results was modified atmosphere packaging (MAP) and the most suitable gas mix ratio was 75% CO₂/25% N₂. The best days for consumption of sea bass packaged with air, MAP (M1, M2, and M3), and vacuum were 4^th, 28^th, 28^th, 16^th, and 20^th days, respectively.     

Preservation of precut white cheese by modified atmosphere packaging

Effects of modified atmosphere packaging (MAP) on storage stability and quality of precut fresh and aged white cheese were investigated. Fresh or aged white cheese was cut into small cubes and packaged in five different atmospheres [0% O₂ + 0% CO₂ + 100% N₂ (MAP1), 10% O₂ + 0% CO₂ + 90% N₂ (MAP2), 0% O₂ + 75% CO₂ + 25% N₂ (MAP3), 10% O₂ + 75% CO₂ + 15% N₂ (MAP4) and aerobic (air)]. Control samples were packaged in brine and vacuum for fresh and aged white cheese, respectively. Changes in gas composition, total plate count, lactococci, lactobacilli, yeast and mould counts, proteolysis, lipolysis, pH, colour, texture and sensory properties were investigated during refrigerated storage. The best packaging treatment for the fresh cheese was MAP3, as it inhibited mould growth and protected the hardness. MAP2 can be recommended for the packaging of the aged cheese, as it decreased lipolysis.     

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     

The effect of modified atmosphere packaging on the microbiological,physical, chemical and sensory characteristics of broadtail squid (Illex coindetii)

The aim of this work was to evaluate the effect of various atmosphere compositions (20% CO₂/80% N₂ for modified atmosphere packaging (MAP) 1, 50% CO₂/50% N₂ for MAP 2, 70% CO₂/30% N₂ for MAP 3 and vacuum packaging) on the microbial (mesophiles, psychrophiles, Pseudomonas spp., Brochothrix thermosphacta and Enterobacteriaceae), physical, chemical [trimethylamine (TMA) and total volatile basic nitrogen (TVBN)] and sensorial characteristics of broadtail squid (Illex coindetii) stored for 10 days at 2 ± 1 °C. All microbial populations were severely restrained by MAP 3 with the exception of Enterobacteriaceae, which seemed to take advantage of the lack of competitive microflora and had enhanced microbial counts on MAP samples (P < 0.05). Colour attributes were better maintained on MAP‐stored samples. Drip loss was less on vacuum‐packaged squids. MAP 2 was the best atmosphere for the preservation of tissue consistency. TMA and TVBN formation was limited by high CO₂ atmospheres, even though both elevated in all studied conditions. Shelf life based on sensory characteristics was determined to be 10, 8, 6, 6 and 4 days for MAP 3, MAP 2, MAP 1, vacuum and control samples, respectively.     

Effect of modified atmosphere packaging and vacuum packaging on the shelf-life of refrigerated chub mackerel (<Emphasis Type="Italic">Scomber japonicus</Emphasis>): biochemical and sensory attributes

The effect of modified atmosphere packaging (MAP 1: 70% CO₂/30% N₂ and MAP 2: 50% CO₂/30% N₂/20% O₂) and vacuum packaging (VP), on the shelf-life of chub mackerel (Scomber japonicus) fillets stored under refrigeration was studied. Quality assessment was based on sensory analysis and biochemical indices determination. Increase in total volatile basic nitrogen (TVBN) and trimethylamine nitrogen (TMAN) followed the order: MAP 1 < MAP 2 < VP < air (control samples). The presence of oxygen into the fish package (air or MAP) resulted in an increase in the 2-thiobarbituric acid (TBA) values in comparison with samples packaged in the absence of oxygen. The most effective MAP used was MAP 1 which contributed to a considerably slower rate of fish spoilage. Based primarily on odour scores it was observed that raw chub mackerel fillets stored in the presence of air remained acceptable up to ca. 11 days, VP and MAP 2 samples up to ca. 15–16 days, while MAP 1 samples up to ca. 20–21 days of storage. On the other hand, flesh texture and flesh colour of all packaged samples received scores above or equal than the acceptability limit up to ca. 13–14 days of storage.     

Sensory comparison of commercial low and high oxygen modified atmosphere packed sirloin beef steaks

The objectives of this study were to investigate the effects of using commercially low and high modified atmosphere packaging (MAP) on quality characteristics of sirloin beef steaks. Gas mixtures used included 80% O₂:20% CO₂ (O₂80), 70% O₂/30% CO₂ (O₂70) and 50% O₂/30% CO₂:20% N₂ (O₂50) and for commercial packs O₂75 ± 5%, CO₂25 ± 5%, < 5% N₂-(O₂Com). All samples were packed in similar tray and packaging film formats. The experimental parameters monitored included microbiological, physiochemical and sensory measurements (naïve assessors). Microbial counts did not exceed the recommended legal ranges over the storage period. However the numbers of LAB (lactic acid bacteria) were the highest for commercially-packed samples (O₂Com) in comparison to laboratory packaged samples (O₂80, O₂70 and O₂50). Commercially-packaged samples eventually spoiled due to the occurrence of off-flavours and off-odours and subsequently were the least acceptable to sensory naïve assessors.     

Microbiological,chemical and sensory assessment of mussels (<Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis>) stored under modified atmosphere packaging

Wild mussels (Mytilus galloprovincialis), were packaged aerobically under vaccum packaging(VP) and modified atmosphere packaging (MAP (50%/50% CO₂/N₂: M1, 80%/20% CO₂/N₂: M2, 65%/35% CO₂/N₂: M3), and stored at 2 ± 1 °C. Quality evaluation was carried out using microbiological, chemical and sensory analyses. Microbiological results revealed that M2 and M3 delayed microbial growth compared to M1. Of the chemical indices determined, the TVB-N and TMA-N values of M2 remained lower than the proposed acceptability limits of 35 mg N/100 g and 8 mg N/100 g, respectively, up to 8 days of storage. All of the MAP and VP mussel samples exceeded these limits after 12 days of storage. All samples retained desirable sensory characteristics during the first 8 days of storage. Based on microbiological and chemical analyses along with sensory evaluation, M2 and M3 gave a longer shelf-life compared with VP and M1. M2 gas mixture was the most effective for mussel preservation.     

Effect of modified atmosphere packaging on the growth of spoilage microorganisms and Listeria monocytogenes on fresh cheese

Queso Fresco has a limited shelf life and has been shown to support the rapid growth of Listeria monocytogenes during refrigerated storage. In addition to improving quality and extending shelf life, modified atmosphere packaging (MAP) has been used to control the growth of pathogenic microorganisms in foods. The objectives of this study were to determine the effects of MAP conditions on the survival and growth of spoilage microorganisms and L. monocytogenes during storage of Queso Fresco manufactured without starter cultures. For L. monocytogenes experiments, cheeses were surface inoculated at ～4 log₁₀ cfu/g before packaging. Inoculated and uninoculated (shelf life experiments) cheeses were placed in 75-µm high-barrier pouches, packaged under 1 of 7 conditions including air, vacuum, or combinations of N₂ and CO₂ [100% N₂ (MAP1), 30% CO₂:70% N₂ (MAP2), 50% CO₂:50% N₂ (MAP3), or 70% CO₂:30% N₂ (MAP4), 100% CO₂ (MAP5)], and stored at 7°C. Samples were removed weekly through 35 d of storage. Listeria monocytogenes counts were determined for inoculated samples. Uninoculated samples were assayed for mesophilic and psychrotolerant counts, lactic acid bacteria, coliforms, and yeast and mold. In general, cheeses packaged under conditions consisting of higher contents of CO₂ had lower pH levels during storage compared with those stored in conditions with lower levels or no CO₂ at all. Similarly, the antimicrobial efficacy of MAP in controlling spoilage microorganisms increased with increasing CO₂ content, whereas conditions consisting of 100% N₂, vacuum, or air were less effective. Mean L. monocytogenes counts remained near inoculation levels for all treatments at d 1 but increased ～2 log₁₀ cfu/g on cheeses packaged in air, vacuum, and 100% N₂ (MAP1) conditions at d 7 and an additional ～1.5 log₁₀ cfu/g at d 14 where they remained through 35 d. In contrast, treatments consisting of 70% CO₂ (MAP4) and 100% CO₂ (MAP5) limited increases in mean L. monocytogenes counts to <1 log₁₀ cfu/g through 14 d and ～1.5 log₁₀ cfu/g by d 21. Mean L. monocytogenes counts increased to levels significantly higher than inoculation (d 0) on cheeses stored in MAP2 and MAP3 on d 21, on d 28 for MAP4, and on d 35 for cheeses stored under MAP5 conditions. Overall, significant treatment × time interactions were observed between air, vacuum, and MAP1 when each was compared with MAP2, MAP3, MAP4, and MAP5. These data demonstrate that packaging fresh cheese under modified atmospheres containing CO₂ may be a promising approach to extend shelf life while limiting L. monocytogenes growth during cold storage.     

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.