Modified Atmosphere Research Articles

Multivariate statistical analysis for the identification of potential seafood spoilage indicators

Volatile organic compounds (VOCs) characterize the spoilage of seafood packaged under modified atmospheres (MAs) and could thus be used for quality monitoring. However, the VOC profile typically contains numerous multicollinear compounds and depends on the product and storage conditions. Identification of potential spoilage indicators thus calls for multivariate statistics. The aim of the present study was to define suitable statistical methods for this purpose (exploratory analysis) and to consequently characterize the spoilage of brown shrimp (Crangon crangon) and Atlantic cod (Gadus morhua) stored under different conditions (selective analysis). Hierarchical cluster analysis (HCA), principal components analysis (PCA) and partial least squares regression analysis (PLS) were applied as exploratory techniques (brown shrimp, 4 °C, 50%CO2/50%N2) and PLS was further selected for spoilage marker identification. Evolution of acetic acid, 2,3-butanediol, isobutyl alcohol, 3-methyl-1-butanol, dimethyl sulfide, ethyl acetate and trimethylamine was frequently in correspondence with changes in the microbiological quality or sensory rejection. Analysis of these VOCs could thus enhance the detection of seafood spoilage and the development of intelligent packaging technologies.

Different Oxygen Transmission Rate Packing Films During Modified Atmosphere Storage: Effects on Asparagus Spear Quality

The aim of this study was to determine suitable oxygen transmission rate (OTR) films for modified atmosphere (MA) storage of asparagus spears (Asparagus officinalis L.), and to examine the related changes in asparagus spear quality. Asparagus spears were packed with 10,000, 20,000, 40,000, 70,000, and 100,000 cc/m2·day·atm OTR film treatments for MA storage, and perforated film (conventional storage) was used as the control. The fresh weight loss rate was less than 1% in all OTR film treatments but not in the control. In all OTR film treatments, ethylene content rapidly increased on the first day of storage, and gradually decreased thereafter to 2.0 μL·L-1 by the final storage day. In the 10,000 cc and 20,000 cc OTR film treatments, carbon dioxide content was maintained within the permissible range for asparagus spears under recommended controlled atmosphere (CA) and MA conditions (5-12%). The oxygen content was maintained between 12% and 20% in all OTR film treatments. Hue angles and total chlorophyll content were highest in the 10,000 cc OTR film treatment in both tips and stems. Visual quality was maintained at a saleable level only in the 10,000 cc OTR film treatment until the final storage day (25 days). Based on sensory evaluation, the least off-odor was detected in the 10,000 cc OTR film treatment, and the most in the control treatment. While the soluble solids content decreased with all film treatments, it was maintained at the highest level in the 10,000 cc OTR film treatment. Vitamin C content decreased with all film treatments during storage, but was maintained at higher levels in the 10,000, 20,000, and 40,000 cc OTR film treatments. The firmness of tips and stems increased with storage duration in all film treatments, stems were firmer under the perforated film, 10,000, and 20,000 cc OTR film treatments. Given these results, the 10,000 cc OTR film treatment is considered the most appropriate for MA asparagus spear storage since visual quality and soluble solids content were maintained, and fresh weight loss, vitamin C content, off-odor, and yellowing were suppressed during storage.

Qualitative Performance and Consumer Acceptability of Starch Films for the Blueberry Modified Atmosphere Packaging Storage

1. Almenar E., Samsudin H., Auras R., Harte B., Rubino M., Postharvest shelf life extension of blueberries using a biodegradable package. Food Chem., 2008, 110, 120–127. Google Scholar

The influence of Intramuscular fat content and collagen characteristics on meat quality and toughness of bovine longissimus thoracisk

The effect of lupin protein concentrate (LPC) addition on selected physicochemical properties, lipid oxidation and sensory quality of pork patties was investigated. LPC was added at the level 1%, 2% and 3%. Patties were packed in vacuum and modified atmosphere (MA) and stored 42 days in a refrigerator while aerobically packed patties were stored 84 days in a frozen state. Patties with LPC showed a lower cooking loss, were less cohesive and juicy, and demonstrated a non-typical flavour compared to the control samples. The inhibitory effect of LPC on lipid oxidation was observed after cooking. During storage this effect was noted mainly in patties with 2% and 3% of LPC stored in frozen state while in vacuum- and MA-stored products it was demonstrated only at some measuring points. After 42 days of storage only sample with 3% LPC packed in modified atmosphere was scored below the borderline of overall acceptance.

Efficacy of Modified Atmospheres in Controlling Museum Insect Pests, Anthrenus verbasci (Coleopetra: Dermestidae) and Tinea pellionella (Lepidopetra: Tineidae) >>

This report presents the results of the first laboratory investigation for the control of insect pests of museums, using the modified atmosphere (MA). The efficacy of using (MA); including argon or nitrogen gases against the larvae and adults of Anthrenus verbasci and Tinea pellionella was evaluated. The lethal time (LT50 and LT95) was determined for different exposure periods at 20ᵒC and 30ᵒC. Argon atmosphere achieved higher mortality than nitrogen for both insect species. The adults were more sensitive than larvae and the mortality was generally higher at elevated temperature. The univariant factorial ANOVA was used to clarify the relationship between the types of gases, the time of exposure and temperature to achieve higher mortality percentages of adults and larvae of both pests. The exposure to an atmosphere of approximately 0.01% oxygen and 99.9% argon or nitrogen was successful in limiting survival of the tested pests among the developmental stages and this condition is accelerated by warmer temperature (30˚C), with the exposure time required to give complete kill, being shorter for argon.

Physicochemical properties, lipid oxidation and sensory attributes of pork patties with lupin protein concentrate stored in vacuum, modified atmosphere and frozen state

The effect of lupin protein concentrate (LPC) addition on selected physicochemical properties, lipid oxidation and sensory quality of pork patties was investigated. LPC was added at the level 1%, 2% and 3%. Patties were packed in vacuum and modified atmosphere (MA) and stored 42days in a refrigerator while aerobically packed patties were stored 84days in a frozen state. Patties with LPC showed a lower cooking loss, were less cohesive and juicy, and demonstrated a non-typical flavour compared to the control samples. The inhibitory effect of LPC on lipid oxidation was observed after cooking. During storage this effect was noted mainly in patties with 2% and 3% of LPC stored in frozen state while in vacuum- and MA-stored products it was demonstrated only at some measuring points. After 42days of storage only sample with 3% LPC packed in modified atmosphere was scored below the borderline of overall acceptance.

Effect of carboxymethylcellulose/candelilla wax coating containing potassium sorbate on microbiological and physicochemical attributes of pears

The main objective of this study was to assess the efficacy of a coating composed of carboxymethylcellulose (CMC), candelilla wax and potassium sorbate (KS) as a post-cold-storage treatment to prevent fungal infections in pears stored under simulated retail display conditions. Moreover, the effect of coating on the physiology and biochemistry of pears was investigated. The coating was very effective against Botrytis cinerea and Monilinia fructigena, while Rhizopus nigricans was the most resistant to KS. The KS-free coating also delayed the fungal growth rate, probably due to modification of the gaseous atmosphere within the fruit tissues. Coated pears showed slower ripening than the uncoated samples, as indicated by unaffected green skin color and inhibited loss of firmness. Unfortunately, coating induced anaerobic respiration and the symptoms of superficial scald in pears. Overall, the results showed that KS can be added into a coating formulation to control fungal growth; however, CMC-based emulsion is not a suitable carrier for KS, when coating is intended to be applied to pears exposed to postharvest cold storage.

Lipid oxidation and color changes of goose meat stored under vacuum and modified atmosphere conditions

The objective of the work was to investigate the color and lipid oxidation changes of goose breast meat packaged in vacuum and modified atmosphere (MA) conditions consisting of 80% O2, 20% CO2, and stored in refrigerated conditions at 4°C. Color stability was monitored by determining total heme pigments concentration; relative concentration of myoglobin, oxymyoglobin, and metmyoglobin; parameters of color L*, a*, b*, and sensory evaluation of the surface color. Lipid stability was measured by determining thiobarbituric acid reactive substances (TBARS). The samples were examined in 24 h after slaughter (unpacked muscles) and on d 4, 7, 9, 11 of storage (muscles packed in vacuum and in MA). Through the time of storage, samples packed in MA had higher TBARS values in comparison to the meat packed in vacuum. For samples packed in two types of atmospheres, the total pigments concentration decreased gradually within 11 d of storage. It was observed that relative metmyoglobin concentration increased whereas relative oxymyoglobin concentration decreased in total heme pigments in the MA stored muscle. The relative concentration of all three myoglobin forms sample packed in vacuum remained unchanged. The color parameters (L*, a*, b*) did not change for 11 d of storage for the vacuum packed meat. The value of the color parameter a* decreased and the value of the color parameters L* and b* increased in the samples packaged in MA. The data prove that if you store goose meat in MA (consisting of 80% O2, 20% CO2) or vacuum, the unchanged surface color is preserved for 9 and 11 day, respectively.Vacuum appears to be a better method as regards the maintaining of lipid stability in goose meat.

Modified Atmospheres as an Environmental Friendly Procedure to Control the Fennel Wasp Systole sp. (Hymenoptera: Eurytomidae)

This study aimed to evaluate different modified atmospheres as an environmental friendly procedure for controlling the fennel wasp Systole sp. The tested modified atmospheres (MAs) contained 10, 20, 30, 40, 50, 60, 70 and 80 % of carbon dioxide (CO2) in air as well as 97 and 98 % of nitrogen (N2). Heavy infested fennel seeds were exposed to these MAs at 15, 25 and 35 °C combined with different exposure periods. The wasp emergence from the infested seeds exposed to MAs decreased gradually by increasing the exposure periods, CO2 or N2 contents and temperatures. MAs containing CO2 were more effective than those containing N2based on the reduction of the adult emergence. Complete reduction in emergence (100 % ) of CO2 treatments was recorded with 60, 70 and 80 % of CO2 at 35°C after 15 days of exposure. Meanwhile, in case of 97 and 98 % of N2, 25 days of exposure were needed to reach zero emergence at 25 and 35 °C. No effect was observed on the emergence of adult wasps from the infested seeds that were expose...

Correlation amongst gas barrier behaviour, temperature and thickness in BOPP films for food packaging usage: A lab-scale testing experience

Permeability of gases in polymers depends strongly upon the polymer structure, the gas type, as well as the conditions of temperature and film thickness. The in-use temperature and thickness of the polymer membrane can play the most important role on preservation and prolongation of food shelf-life. In this work the gas transmission parameters of six Bi-axially Oriented Polypropylene (BOPP) films were investigated as a function of temperature, gas type and thickness. O2, CO2, N2, N2O, C2H4, Air (79%N2/21%O2) and Modified Atmosphere (MA) of 79%N2O/21%O2 were used as test gas. In order to understand the kinetic of the process, by the activation energy determination, samples were tested at a different temperature, from 10 °C to 40 °C. Gas Transmission Rate (GTR), solubility (S) and diffusion (D) relationship was investigated. The gas/thickness/temperature correlation was reflected in the obtained perm-selectivity ratios and a good linear correlation was found only at 23 °C. Deviations recorded were attributed to temperature fluctuations. Gas transmission process follows the Arrhenius model while the solubility/diffusion process shows consistent deviation, correlated to the temperature and the thickness of the film. By Differential Scanning Calorimetry (DSC) a different crystallinity percentage was recorded, whose influence was evidenced only in the sorption/diffusion processes. The melting temperature remained unchanged. FT-IR Spectroscopy was also carried out to confirm the morphology.

Effects of modified atmosphere, anti‐browning treatments and ultrasound on the polyphenolic stability, antioxidant capacity and microbial growth in fresh‐cut apples

AbstractThis study addressed the changes in polyphenolic stability and antioxidant capacity in fresh‐cut apples packaged in modified atmosphere (MAP) as a result of (i) minimal processing parameters (type of cultivar, anti‐browning treatments, and the length of storage); (ii) superficial browning; (iii) ultrasound treatment; and (iv) microbial growth during storage at 4 °C for 14 days. Studied cultivars were Cripps Pink and Golden Delicious. Anti‐browning agents were ascorbic with citric acid and sole Ca‐ascorbate that were both combined with the ultrasound. Identified phenolic compounds in all samples were chlorogenic and p‐coumaroylquinic acid, quercetin, epicatechin, and phloridzin. Cripps Pink was richer on flavonoids and had the higher antioxidant capacity than Golden Delicious. Application of any anti‐browning treatments did not influence quantities of phenolic compounds, but they showed an improved antioxidant capacity in comparison with untreated samples. Phenolic compounds were stable and antioxidant capacity decreased during storage. Microbial growth had no association with the majority of phenolic compounds (except epicatechin), where it was possible that microorganisms oxidized epicatechin to quercetin together with apple respiratory processes.Practical applicationsFresh‐cut production represents large portion of the international food markets as consumers increasingly demand ready‐to‐eat products. However, these products have a very short shelf‐life with strong impacts on economic gains from such production. Modified atmosphere packaging (MAP) is a very popular industrial preservation technique for prolonging freshness of ready‐to‐eat apples and other foods. Polyphenolics naturally present in apples have various health benefits and favorable influence on nutritive value. Currently, there is a scarcity of available data that simultaneously associates changes in polyphenolic content with minimal processing; apple respiration; storage and superficial browning. This type of data has both, economic and nutritive value for the fresh‐cut production as it is associated with extension of the shelf‐life, plus it is directly related with the superficial browning in this perishable produce.

Light-Induced Discoloration of Sliced Packaged Salami is Non-Reversible

Objectives Sliced fermented salami sausages packaged in modified atmospheres (MA) are prone to discoloration by a combination of residual O2 in the headspace and light at retail display. To avoid discoloration, packages of uncooked salami should be stored in darkness until all O2 is removed by internal processes in the product, usually within a few days. The aim of this study was to determine if the color of salami could return from brown to red by extended illuminated display in pack-ages with MA`s, in which residual O2 was present in the early, but not the later stage of display. Materials and Methods Dry fermented raw salami was produced with pork, pork fat, beef, starter culture, salt, sugars and 120 ppm sodium nitrite. Packages with 150 g sliced salami were inserted with air and CO2 through self-sealing septas to contain approximately 5% O2, 50% CO2 and 45% N2 with a gas to product ratio of 1.1 to 1. The lower and up-per films for the packages were laminates with EVOH as O2 barrier. The transparent packages were exposed to continuous LED light type 68 W 830 (Glamox AS, Oslo, Norway) of 3.5 W/m2 (1100 lux) for 10 d at 20°C. Concentrations of O2 in the packages were measured at the time of packaging and d 1, 2, 3, and 4 of display with a Checkmate 3 instrument (Dansensor, Ringsted, Denmark). CIE L*a*b* values (lightness, redness and yellowness) were analyzed through the packaging films at d 0, 1, 2, 3, 4, 7, and 10 of display with a Minolta Chroma Meter CR-400 (Konica Minolta Inc., Tokyo, Japan). The experiment included 3 batches of salami with 5 packages per batch. Analysis of variance was performed for all data using a general linear model in Minitab 17 Statistical Software (Minitab Inc., State College, PA, USA), and means were separated by Tukey’s multiple comparison test. Results Concentrations of O2were reduced from the initial 5% to 0% at d 4 of display. The initial a* values of sausages from the 3 batches were approximately 16, which is fully red. Within 2 d of display, a* values were substantially reduced to 9 to 10 (P

Evaluation of the antioxidant activity of Betula pendula leaves extract and its effects on model foods

Context: Betula pendula Roth (Betulaceae) exhibits many pharmacological activities in humans including anticancer, antibacterial, and antiviral effects. However, the antioxidant activity of BP towards lipid degradation has not been fully determined. Objective: The BP ethanol and methanol extracts were evaluated to determine antioxidant activity by an in vitro method and lyophilized extract of BP was added to beef patties to study oxidative stability. Materials and methods: Antioxidant activities of extracts of BP were determined by measuring scavenging radical activity against methoxy radical generated by Fenton reaction 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (TEAC) radical cation, the oxygen radical absorbance capacity (ORAC) and the ferric reducing antioxidant power (FRAP) assays. The lipid deterioration in beef patties containing 0.1% and 0.3% (w/w) of lyophilized extract of BP stored in 80:20 (v/v) O2:CO2 modified atmosphere (MAP) at 4 °C for 10 days was determined using thiobarbituric acid reacting substances (TBARS), % metmyoglobin and colour value. Results: The BP methanol extract revealed the presence of catechin, myricetin, quercetin, naringenin, and p-coumaric acid. The BP ethanol (50% w/w) extract showed scavenging activity in TEAC, ORAC and FRAP assays with values of 1.45, 2.81, 1.52 mmol Trolox equivalents (TE)/g DW, respectively. Reductions in lipid oxidation were found in samples treated with lyophilized BP extract (0.1% and 0.3% w/w) as manifested by the changes of colour and metmyoglobin concentration. A preliminary study film with BP showed retard degradation of lipid in muscle food. Conclusion: The present results indicated that the BP extracts can be used as natural food antioxidants.

Rationalization of storage atmospheric composition of freshly treated white button mushroom (Agaricus bisporus) packed with moisture absorber

Mushrooms are fast respiring and highly perishable commodities. Thus, modification of the storage atmosphere as an adjunct to low temperature can be effective in extending their shelf-life. Therefore, the present study was conducted to investigate effect of moisture absorber on respiration rate of packed white button mushroom stored at two different conditions. The freshly harvested mushrooms after washing with different solutions of CaCl2, KMS and NaCl were packed in polypropylene and stored at ambient (22+2° C) and refrigerated (4+2° C) conditions. Analysis conducted at 3 days interval showed the polypropylene pack containing the mushroom treated with 0.5 % CaCl2 + 0.5 % KMS + 0.5 % NaCl had less fluctuation in O2 and CO2 content at 3 days after treatment at ambient condition and 9 days after treatment at refrigerated condition. In another study, the mushrooms were packed with 12 g moisture absorber and subjected to the storage period of 0, 3, 6 and 9 days at ambient and refrigerated conditions. Mushrooms stored at refrigerated condition after washing with 0.5 % CaCl2 + 0.5 % KMS + 0.5 % NaCl and packing in polypropylene pouches with 12 g absorber showed best results when compared with mushroom packed without absorber.

Shiitake mushroom packages tuned in active CO2 and moisture absorption requirements

Abstract Active packages of shiitake mushrooms with CO 2 - and moisture-absorbing sachet or pad were designed and tested in their effectiveness in quality preservation for a given shelf life of 5 days at 10 °C. Sachets of sodium carbonate (SC) and mix of SC and calcium hydroxide (CH), and SC-impregnated cotton pad were characterized in their CO 2 and moisture absorption properties to calculate proper amounts of the active components capable of scavenging the required amounts of CO 2 and water vapour. The demands of CO 2 and water vapour absorptions to maintain the desired modified atmosphere (MA) and avoid moisture condensation inside the packages were determined from mass balance relationships comprising the mushroom respiration/transpiration and gas transmission through the package layer. Super-absorbent polymer (SAP) of polyacrylate was added as a supplement material to bring about the water vapour absorption required further to attain non-saturated humidity condition. Sachet combined of SC and SAP attached inside the package of 180 g mushrooms maintained its atmosphere of 10.7–11.6% O 2 and 7.1–8.9% CO 2 concentrations at steady state helping to preserve the quality best. Proper combination of CO 2 and moisture absorbers can be useful tool to create the desired MA and alleviate saturated humidity conditions in packages of the commodities sensitive to high CO 2 and moisture condensation.

Effect of Product Microstructure and Process Parameters on Modified Atmosphere Packaged Bread

The objective of this study was to examine bread microstructure, oxygen diffusion properties, and gas exchange between bread and headspace after packaging in modified atmosphere (MA). Breads were produced at laboratory scale, and industrially produced breads were included as a reference. X-ray microtomography was applied to characterize the microstructure of the bread samples. For each sample type, oxygen diffusivity was calculated based on microstructural parameters. The samples for gas analyses were packaged under MA using vacuum compensation, using two vacuum strengths during the air evacuation step. The total porosity of all laboratory samples was above 75%, except for the side and bottom crusts which had a lower porosity (<70%). The porosities of the crumb and the side crust of the commercial bread were 80 and 76%, respectively. The connectivity density of the crumbs of the laboratory and commercial breads was 8 and 10 mm−3, respectively. The crust showed a larger resistance to oxygen diffusion than the crumb, but for both bread regions, the diffusivity was maximally ten times smaller than that of oxygen in air. When considering all data obtained from the gas analysis in the headspace immediately after packaging, oxygen levels of 0.1 ± 0.1% for strong vacuum and 3.8 ± 2.9% for weak vacuum were obtained, which differed significantly (p < 0.05). The results of the laboratory samples corresponded well to those of industrially baked breads. It was concluded that vacuum strength during packaging determines gas transport in bread after packaging.

CFD Analysis of Coffee Packaging in Capsules using Gas Flushing Modified Atmosphere Packaging

Abstract The aim of this work is to analyze, by means of CFD (Computational Fluid Dynamics), the gas flow in a packaging machine used to fill polymeric capsules with coffee. The final goal is to optimize the geometric shape of some mechanical components in the machine’s sealing station in order to reduce the inert gas consumption achieving an O2 residual which is constantly equal or below 1 % by mass in the center of the capsule. The fluid domain has been obtained starting from the 3D CAD model of the sealing station of the packaging machine. The CAD software SolidWorks has been used to design the system, while Ansys CFX 14.5 software has been used for the CFD analysis. The CFD model has been validated by comparing its results with those obtained by experimental tests. The modified solution allows reducing the average O2 residual from about 3 % to less than 1 %.

Impacts of low and super-atmospheric oxygen concentrations on quality attributes, phytonutrient content and volatile compounds of minimally processed pomegranate arils (cv. Wonderful)

This study investigated the impact of modified atmosphere (MA) storage: at low oxygen (O2) (MA-1; 5kPa O2+10kPa CO2+85kPaN2), (MA-2; 10kPa O2+5kPa CO2+85kPaN2); super-atmospheric O2 (MA-3; 70kPa O2+10kPa CO2+85kPaN2); and air (MA-4; 21kPa O2+0.03kPa CO2+78kPaN2) on the physicochemical, phytonutrient, volatile organic compounds (VOCs) and microbiological quality of minimally processed ‘Wonderful’ pomegranate arils stored at 5°C for 12 d. In addition, the effect of temperature fluctuation on the physical and microbiology quality of arils was evaluated. Samples were removed from cold storage on each sampling day, and kept for 2 d at ambient (20°C) condition. Low O2 atmosphere (MA-1) best maintained phytonutrient content of arils at 5°C. Aerobic mesophilic bacteria, yeast and mould counts were found to be significantly lower under super-atmospheric O2 (MA-3) storage in comparison to other treatments at 5°C and ambient. A total of 25 volatile organic compounds (VOCs) were detected and identified for pomegranate ‘wonderful’ across the different MA conditions. Highest relative composition of VOCs was found in samples stored under MA-3. Temperature fluctuation had a significant impact on the physical and microbiology quality of pomegranate arils.

Characterization of microbial population of breba and main crops (Ficus carica) during cold storage: Influence of passive modified atmospheres (MAP) and antimicrobial extract application

The purpose of this work was to study the changes of bacterial and fungal population of breba fruits such as ‘Banane’ and ‘San Antonio’ as well as ‘Cuello Dama Negro’, ‘Cuello Dama Blanco’ and ‘San Antonio’ fig cultivars stored in passive modified atmospheres (MAP) by the use of three different microperforated films (M10 with 16 holes; M30 with five holes and M50 with three holes). Moreover the effects of the application of aqueous soy polyphenolic antimicrobial extract (APE), alone or combined with MAP, were also studied for ‘Cuello Dama Negro’ and ‘Cuello Dama Blanco’ fig cultivars. Bacteria and fungi isolates were identified by PCR-RFLP of 16S rRNA and ITS regions, respectively, and subsequently sequence of the different patterns obtained. The results indicated that Pseudomonas gessardii, Pantoea agglomerans and Enterobacter asburiae were the main species of bacteria found in all the treatments studied. The fungal species identified were Aureobasidium pulullans, Cladosporium cladosporioides and Alternaria alternata, which were found in a lower percentage in fruit stored in MAP and fruits treated with antimicrobial extracts, as this treatments allowed to reduce the microbial growth of moulds and yeasts. Thus, the application of treatments such as M30, M50 or the combination of MAP with antimicrobial extract was highly effective to control fruit spoilage in fig and breba crops.

Bacterial population dynamics and sensorial quality loss in modified atmosphere packed fresh-cut iceberg lettuce

The end of shelf life of fresh-cut iceberg lettuce packed in modified atmosphere (MA) is determined by its visual quality and by its microbial load. The total microbial load should not exceed 6–7 log CFUg−1 mesophilic counting and be free of human pathogens. Not much is known about specific interactions between the levels of specific spoilage micro-organisms and the sensorial quality attributes of the fresh-cut product. We studied the changes in sensorial quality attributes and the growth and population dynamics of microorganisms in three independent batches of MA packed fresh-cut iceberg lettuce stored at 7°C.The sensorial quality of the fresh-cut product was daily evaluated by visual determination of color, shape (indication of crispness) and discoloration (browning); together these attributes were translated into an Overall Visual Quality (OVQ) value. In addition, off-odour and sourness production were scored immediately after opening of the bags. Samples of the fresh-cut product were taken to determine the total microbial load and to investigate the bacterial species composition using mass sequencing analysis.The decrease of OVQ over time showed a down sigmoid curve, reaching the limit of consumer acceptance after about eight days. Total bacterial counts increased from about 5 log at day 1 to about 8 log colony forming units (CFU) per gram at day 7. Initially, Pseudomonas species were dominant but when the package became anaerobic, lactic acid bacteria (LAB), in particular Leuconostoc spp. and Lactococcus spp. became more abundant and dominated the bacterial population. Especially the rapid growth of Leuconostoc species correlated with development of a sour off-odour, represented by the accumulation of acetic and lactic acids in the product and the decrease in OVQ. Results indicate that metabolites produced by LAB are responsible for off-odour production and loss of sensorial quality.Based on this knowledge, new strategies for shelf-life improvement may be designed to prevent the dominance of LAB in fresh cut lettuce or make shelf-life better predictable based on initial counts of LAB, that may assist the industry and retail to reduce food waste.