Weeks Of Cold Storage Research Articles

Evaluating serotype-specific survival of Listeria monocytogenes and Listeria innocua on wax-coated Granny Smith apples during storage

Listeria monocytogenes serotypes 1/2a, 1/2b, and 4b are implicated in over 90 % of human listeriosis cases; however, information regarding the serotype-specific survival of L. monocytogenes on apples remains limited. This study evaluated the survival dynamics of these serotypes, using two sets of strains, on Granny Smith apples (GSA) and examined the impact of wax-coating on their survivability during storage. The fate of Listeria innocua on GSA during commercial refrigerated air (RA) storage was also investigated. Results revealed distinct behaviors among L. monocytogenes serotypes. The culturable count of the serotype 4b strain on apples decreased significantly (P < 0.05) by 1.36 log CFU/apple within the first 48 h post-inoculation at ambient temperature. In contrast, counts of serotypes 1/2a and 1/2b strains significantly increased (P < 0.05) by 0.44 and 0.50 log CFU/apple, respectively, during this 48-h attachment period. Over the subsequent 12 weeks of cold storage, serotypes 1/2a and 4b remained stable on GSA, while 1/2b decreased by 1.68 log CFU/apple. Wax coating had a minor impact on L. monocytogenes survival on GSA under both cold and ambient storage conditions, regardless of serotypes. During 18 weeks of commercial RA storage, L. innocua exhibited a gradual decrease of 1.76–1.96 log CFU/apple on wax-coated GSA. Yeasts and molds showed no significant changes in populations due to wax coating, maintaining counts between 5.5 and 5.7 log CFU/apple by the end of the 18-week storage. Additionally, wax coating enhanced quality attributes, significantly preventing (P < 0.05) firmness loss and internal browning compared to unwaxed apples at the conclusion of storage. This study highlights the serotype-specific survival traits of selected L. monocytogenes produce-outbreak isolates on apples, emphasizing the importance of understanding the distinct behaviors of different serotypes.

Understanding the Genetic Basis of Blueberry Postharvest Traits to Define Better Breeding Strategies.

Blueberry (Vaccinium spp.) is among the most-consumed soft fruit and has been recognized as an important source of health-promoting compounds. Highly perishable and susceptible to rapid spoilage due to fruit softening and decay during postharvest storage, modern breeding programs are looking to maximize quality and extend the market life of fresh blueberries. However, it is uncertain how genetically controlled postharvest quality traits are in blueberries. This study aimed to investigate the prediction ability and genetic basis of the main fruit quality traits affected during blueberry postharvest to create breeding strategies for developing cultivars with an extended shelf life. To achieve this goal, we carried out target genotyping in a breeding population of 588 individuals and evaluated for several fruit quality traits after one day, one week, three weeks, and seven weeks of postharvest storage at 1 °C. Using longitudinal genome-based methods, we estimated genetic parameters and predicted unobserved phenotypes. Our results showed large diversity, moderate heritability, and consistent predictive accuracies along the postharvest storage for most of the traits. Regarding fruit quality, firmness showed the largest variation during postharvest storage, with a surprising number of genotypes maintaining or increasing their firmness even after seven weeks of cold storage. Our results suggest that we can effectively improve blueberry postharvest quality through breeding and use genomic prediction to maximize the genetic gains in the long term. We also emphasize the potential of using longitudinal genomic prediction models to predict fruit quality at extended postharvest periods by integrating known phenotypic data from harvest.

Effects of 2'-fucosyllactose on the viability of starter cultures and Bifidobacterium strains of human origin in yogurt during refrigerated storage.

2'-Fucosyllactose (2'-FL) is postulated to provide health benefits and promote the growth of probiotics. This work was undertaken to study the effects of 2'-FL on the viability of starter cultures and Bifidobacterium strains of human origin in yogurt during refrigerated storage. Yogurts were produced containing 2'-FL (0 or 2g/L) and Bifidobacterium strains of human origin (Bifidobacterium longum subsp. longum BB536 or Bifidobacterium longum subsp. infantis ATCC 15697) at a concentration of at least 109 CFU/mL. All yogurts were stored at 4°C for 5weeks. Results showed that 2'-FL was stable in yogurts for at least 5 weeks of cold storage, and the addition of 2'-FL did not significantly alter yogurt fermentation parameters, associated metabolites, and the viability of mixed yogurt starter cultures and Bifidobacterium strains (p>0.05). The addition of bifidobacteria had a negative impact (p<0.05) on the survival rate of starter cultures, Streptococcus thermophilus and Lactobacillus delbureckii subsp. bulgaricus. Meanwhile, it is difficult to maintain a high survival rate of bifidobacteria in final yogurt products, and the addition of 2'-FL could not enhance the viability of bifidobacteria. B. longum BB536 survived at a level higher than 106 CFU/g for 28 days, while B. infantis ATCC15697 maintained this level for only 7 days. In summary, this study has shown the impact of 2'-FL and bifidobacterial species on yogurt properties, and results suggest that it is promising to use 2'-FL in yogurt products as a prebiotic. PRACTICAL APPLICATION: Yogurt is known for its beneficial effects on human health and nutrition. This study reported the production of symbiotic yogurt containing bifidobacteria and 2'-fucosyllactose (2'-FL) as a functional food for specified health uses. The viability of yogurt starter cultures and probiotic bifidobacterial strains was analyzed in this study. Moreover, this research demonstrated that 2'-FL could be added to yogurt without affecting the characteristics of yogurt significantly.

Functional beverage production through lactic acid fermentation of black chokeberry (Aronia melanocarpa) juice

The aim of the present study was to evaluate the microbiological, physicochemical, and nutritional features of black chokeberries juice fermented by a novel potentially probiotic strain (Lacticaseibacillus paracasei SP5) immobilized on delignified wheat bran (DWB) and orange peel for 2 days at 30 °C and for 28 days at 4oC. In general, application of immobilization led to elevated viabilities of L. paracasei SP5 (>8.8 log cfu/mL) in all studied periods of fermentation and subsequently ameliorated fermentative capacities. The application of orange peel as immobilization support led to better total phenolic content of the fermented juice after the 48 h fermentation (10.4 GAE g/L) and the 4th week of cold storage at 4 °C (13.9 GAE g/L), compared to the respective results obtained through the application of immobilized on delignified wheat bran and the unfermented juice. Higher antioxidant activity (AA) was recorded in the fermented juices by immobilized cells in all studied periods compared to the unfermented juice. Specifically, remarkable levels were obtained through the application of immobilized L. paracasei SP5 on orange peel (79.8 mmol Trolox/L at the 3rd week of cold storage), while the respective values were slightly lower when delignified wheat bran applied and much lower in the case of unfermented juice. Chokeberry juices fermented by both immobilized cells retained sufficient volatile compounds (alcohols, ketones, and esters) even after the 4th week of cold storage, in contrast to unfermented chokeberry juice.

Predicting Soluble Solids Concentration of ‘Geneva 3’ Kiwiberries Using Near Infrared Spectroscopy

Near infrared (NIR) spectroscopy can be applied to nondestructively assess soluble solids concentration (SSC) of ripening, physiologically mature ‘Geneva 3’ kiwiberries (Actinidia arguta). Spectrographic signatures were captured using a handheld NIR produce quality meter to build predictive models of internal fruit quality for ‘Geneva 3’ kiwiberries that had been held under cold storage (CS) conditions (0 to 1 °C, &gt;90% relative humidity) as well as those not subjected to CS. The CS model, constructed using scans of 133 berries following 4 to 6 weeks in CS, predicts SSC using NIR wavelengths in the range of 729 to 975 nm. A total of 507 berries fresh from the vine were used to construct a predictive model for SSC of non-CS fruit using the same wavelength range. In each case, model predictive performance was investigated using split-half cross-validation, resulting in mean absolute error (MAE) values of 1.2% and 0.8% SSC for the CS and non-CS model, respectively. Each full model was then used to predict SSC of kiwiberries subjected to the alternative CS condition. The non-CS model maintained a low MAE (1.6% SSC) when applied to CS fruit, but the MAE of the CS model applied to non-CS fruit rose considerably (4.5% SSC). The performance of a combined model was tested against both CS and non-CS models, and a benefit to using tailored, CS-specific models was found, particularly in light of cross-seasonal results. As it has proven in many crops, NIR spectroscopy appears to be a promising tool for nondestructively assessing SSC in ‘Geneva 3’ kiwiberry fruit, with accuracy being enhanced by training models specific to postharvest regimes and/or defined ranges of SSC.

Bee venom: A potential natural alternative to conventional preservatives for prolonging the shelf-life of soft cheese ‘Talaga’

The study aims to explore bee venom (honey-BV) as a potential natural preservative for "Tallaga" soft cheese. Characterization of the active compounds in honey-BV was conducted via chromatographic analyses. Antimicrobial efficacy against pathogenic bacteria and fungi was evaluated, and minimum inhibitory concentration (MIC) was determined. Subsequently, honey-BV was applied to Tallaga cheese at 15 mg/g concentrations. The main active ingredients identified in bee venom were apamin (2%) and melittin (48.7%). Both concentrations of bee venom (100 and 200 mg/mL) exhibited significant antifungal and antibacterial properties against tested organisms, with MIC values varied from 0.2 to 0.5 mg/mL for bacteria to 3–13 mg/mL for fungi. Application of honey-BV in Tallaga cheese resulted in complete elimination of Staphylococcal populations after 2 weeks of cold storage, with no detectable growth of molds or yeasts throughout the storage period. Additionally, a steady decrease in aerobic plate count was observed over time. In summary, honey-BV holds promise as a natural preservative for soft cheese, however, more investigation is required to optimize the concentration for economic viability, taking into account health benefits and safety considerations.

Tissue culture and cryopreservation in the utilization and conservation of genetic resources of Norway spruce (Picea abies) and elms (Ulmus glabra, U. laevis)

In this work, tissue culture techniques were developed for two purposes: the production of Norway spruce (Picea abies [L.] Karst.) forest regeneration material with somatic embryogenesis (I–III) and the conservation of genetic resources of European white elm (Ulmus laevis Pall.) and wych elm (Ulmus glabra Huds.) with cryopreservation and organogenesis (IV, V). In P. abies somatic embryogenesis, zygotic embryos are used as explants to produce embryogenic tissue, which can be matured into copies of the initial embryo for clonal propagation. In Paper I Plantform temporary immersion system bioreactors were tested for P. abies somatic embryogenesis. The production of cotyledonary embryos in bioreactors required adding steps to the protocol and the bioreactors were laborious to use. In Paper II growing embryogenic tissue in suspension culture was evaluated. Suspension culture is more scalable than propagation on a semi-solid media. However, it required rinsing the tissue before maturation and it could benefit from optimizing the media composition. Higher hydrogen peroxide content was observed in embryogenic tissue grown in suspension than on semi-solid media, but no conclusive evidence of higher oxidative stress in suspension culture was found. In Paper III, filter disc cultures grew faster than clumps on semi-solid media and produced slightly more embryos. The storage compound profile of somatic embryos was most similar to the zygotic embryos at 4–8 weeks of cold storage. In organogenesis, plant organs and new plants are clonally propagated from meristematic tissues or through a callus phase. In Paper IV, a micropropagation protocol was developed to regenerate U. laevis and U. glabra dormant buds from cryostorage. Both elm species are endangered in Finland and globally threatened by Dutch elm disease. The main challenges were surface sterilization and poor regeneration of U. glabra from cryostorage. In Paper V, dehydration was successfully implemented to improve the regeneration rate.

Salicylic Acid Treatment Improves the Shelf Life and Quality of ‘Cheonghyang’ Grapes during Cold Storage

The storage capacity of ‘Cheonghyang’ grapes, a promising grape cultivar developed in South Korea, is a critical factor affecting their commercial viability. This study investigates the impact of salicylic acid (SA) treatment on the storage capacity of ‘Cheonghyang’ grapes. The effects of SA treatment at different concentrations were assessed by comparing fruit characteristics and enzyme activity related to shelf life after two and four weeks of cold storage in comparison with an untreated control group. The findings reveal that SA-treated grapes exhibited reduced water loss and improved firmness, leading to a lower occurrence of unmarketable berries. Furthermore, enzymes involved in pectin degradation, such as pectate lyase and polygalacturonase, were reduced in the SA-treated group, while antioxidant activity-related enzymes, including catalase, peroxidase and superoxide dismutase, were more active than in the control group. The most effective control of enzyme activities was observed at an SA concentration of 2 mM, which demonstrated the least decline in fruit quality among the tested SA concentrations in this study. These results indicate that SA is a highly effective substance for maintaining the storability of ‘Cheonghyang’ grapes under conditions of low-temperature storage after harvest.

Antioxidant Systems and Quality in Sweet Cherries Are Improved by Preharvest GABA Treatments Leading to Delay Postharvest Senescence.

γ-Aminobutyric acid (GABA) plays important roles in plant development, including the maintenance of fruit quality when applied as postharvest treatment. However, little information is available about the effects of preharvest GABA treatments. Thus, GABA (10, 50 and 100 mM) was applied as foliar spray at key points of fruit development in three sweet cherry cultivars and over two years. The results show that quality parameters, such as total soluble solid content, titratable acidity and firmness were higher in the fruit from GABA-treated trees than in the controls, either at harvest or during four weeks of cold storage. In addition, the total phenolic and total and individual anthocyanin concentrations were also enhanced by GABA treatments and the fruit color was improved. The activities of the antioxidant enzymes catalase, ascorbate peroxidase and peroxidase were also enhanced by the GABA treatments. The most effective concentration was 50 mM, which led to extending the storage period of sweet cherries with high quality traits to up to four weeks, while for the controls this was two weeks. Thus, GABA treatment had a clear effect on delaying the postharvest ripening and senescence processes in sweet cherries, with an additional effect on enhancing the content of bioactive compounds, such as phenolics and anthocyanins, with antioxidant properties and health benefits.

Mechanism of enhanced freshness formulation in optimizing antioxidant retention of gold kiwifruit (Actinidia chinensis) harvested at two maturity stages

Kiwifruit exhibits a climacteric ripening pattern and has as an extremely perishable nature. Considering that high perishability leads to a loss in antioxidants and overall nutritional quality. This study aimed to examine the efficacy of enhanced freshness formulation (EFF), a hexanal-based formulation containing antioxidants such as geraniol, α-tocopherol and ascorbic acid, on maintaining the bioactive compounds of gold kiwifruit (cv. ‘Y368’) harvested at two maturity stages. Kiwifruits were treated with three treatments, namely, control (untreated fruit), 0.01 and 0.02% (v/v) EFF. Fruits were treated with 8 weeks of cold storage at 0°C and 90% relative humidity, then transferred to 20°C for 8 days. Three bioactive compounds (ascorbic acid, total phenolics and flavonoids), antioxidant capacities using DPPH and FRAP assays, polyphenol oxidase, ascorbate oxidase, phenylalanine and tyrosine ammonia lyase enzyme activities were evaluated. The results showed that EFF significantly (p &amp;lt; 0.05) influenced bioactive compounds, antioxidant capacities and the activity of enzymes involved in the synthesis and oxidation of bioactive compounds. The maturity stage significantly influenced the content of bioactive compounds. Later harvested kiwifruit had greater content of bioactive compounds, compared to earlier harvested kiwifruit. The total phenolic content was 0.77, 1.09 and 1.22 mg GAE g−1 FW for control, 0.01 and 0.02% EFF, respectively. The FRAP antioxidant concentration was 0.76, 0.91 and 0.96 μmol Fe (II) g−1 FW for control, 0.01 and 0.02% EFF. The findings illustrate the capacity of EFF to optimize bioactive compounds and storability of kiwifruit during postharvest storage.

Influence of temperature and exposure time of cold storage on the fitness of Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae)

Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) is an important biological control agent that parasitizes larvae and pupae of Coleopteran pests. Cold storage can extend the shelf life of parasitoids for use in biological control programs. To understand the effects of cold storage on performance of A. calandrae, the adult survival, longevity, parasitism rate, and fecundity of A. calandrae after cold storage were investigated. Newly emerged A. calandrae females were stored at three constant temperatures (5, 10, and 15 °C) for 1, 2, 3, 4, 5, and 6 weeks. Both temperature and storage period significantly affected longevity, parasitism, progeny, and sex ratio of A. calandrae. Significant reduction in longevity was observed at 5 °C. After 1 week of cold storage, the longevity of A. calandrae at 5 °C decreased to 8 d, compared to 11 d in the control. However, there was no significant difference on the longevity and parasitism rate when the female wasps were stored at 15 °C for 3 weeks compared to control. The number of progeny gradually decreased with increasing storage period at 15 °C, and the maximum of progeny was observed for the control, 83.33 followed by 75.46 (1 week), 71.26 (2 weeks), and 68.40 (3 weeks). After cold storage at 5 °C for 1 week and 15 °C for 3 weeks, female-biased sex ratios in progeny were 0.53 and 0.55, respectively. Overall, storage at 15 °C for 3 weeks had the least negative impact on adult survival, longevity, parasitism rate, and progeny of A. calandrae wasps.

First Report of Black Spot Disease Caused by Alternaria alternata on Persimmon Fruit in China.

Sweet persimmon is native to Japan and valued for its fruit, which are high in sugar and vitamins. In October 2021, symptoms were observed on persimmon (Diospyros kaki L. cv. Yangfeng) fruits in cold storage room in Suiping county, Henan Province (32.59 °N, 15 113.37 °E). Initially, small circular dark-brown spots were visible on the fruit rind, turning into irregular sunken dark areas, and eventually rotting 15% of 200 fruits after four weeks of cold storage (10°C, 95% relative humidity). To isolate the causal agent, 10 fruits of symptomatic tissues (4 mm2) were surface-sterilized in 2% sodium hypochlorite (NaOCl) for 1 minute, washed three times in sterile distilled water, then aseptically transferred to potato dextrose agar (PDA) and incubated for 7 days at 25°C. Fungal colonies were isolated from plant tissue, and on three colonies of similar morphology, single-spore isolation was performed. On PDA, the isolates produced circular colonies of fluffy aerial mycelia, gray-brown in the center with gray-white margins. Conidia were dark brown, obclavate or pyriform, with 0 to 3 longitudinal septa and 1 to 5 transverse septa, and a size range of 19.2 - 35.1 × 7.9 - 14.6 μm (n=100). Conidiophores were olivaceous, septate, straight, or bent, with a length of 18 - 60 × 1 - 3 μm (n=100). These morphological characteristics identify the isolates as Alternaria alternata (Simmons. 2007). Genomic DNA was extracted from a representative isolate YX and re-isolated strain Re-YX by cetyltrimethylammonium bromide (CTAB). The primers of ITS1/4, Alt-F/R, GPD-F/R, EF1/2, EPG-F/R (Chen et al. 2022), RPB2-5F/7cR (Liu et al. 1999), and H3-1a/1b (Lousie et al. 1995) were used to amplify the partial internal transcribed spacer (ITS) region, Alternaria major allergen (Alt a1), Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), translation elongation factor 1-alpha (TEF), endo-polygalacturonase (endoPG), RNA polymerase second largest subunit (RPB2) and Histone 3 (His3), respectively. GenBank accession No of ITS, Alt a1, GAPDH, TEF, endoPG, RPB2, His3 were ON182066, ON160008 to ON160013 for YX and OP559163, OP575313 to OP575318 for Re-YX respectively. Sequence data of Alternaria spp. were downloaded from GenBank and the BLAST analysis showed 99%-100% homology between various A. alternata strains (ITS: MT498268; Alt a1: MF381763; GAPDH: KY814638; TEF: MW981281; endoPG: KJ146866; RPB2: MN649031; His3: MH824346). A phylogenetic analysis based on ITS, Alt a1, GAPDH, TEF, and RPB2 sequences using MEGA7 (Molecular Evolutionary Genetics Analysis) revealed that the isolate YX and Re-YX were clustered in A. alternata clade (Demers M. 2022). For the pathogenicity test, seven-day-old cultures were used to create spores suspensions (5.0 × 105 spores/mL) of each of the three isolates. Ten µL aliquots from each isolate were inoculated onto ten needle-wounded persimmon fruits; ten additional fruits were inoculated with water only to serve as controls. The pathogenicity test was three replications. Fruits were deposited in a climate box at 25°C, 95% relative humidity. Seven days post-inoculation, the wounded fruit treated with spore suspensions displayed black spot symptoms similar to the symptoms on the original fruit. There were no symptoms on the control fruits. The strain Re-YX was re-isolated from the symptomatic tissue of inoculated fruits and its identity confirmed using the morphological and molecular methods previously mentioned, fulfilling Koch's postulates. The persimmon fruit rot caused by A. alternata had been reported in Turkey and Spain (Kurt et al., 2010, Palou et al., 2012). According to our knowledge, this is the first report of black spot disease on persimmon fruits caused by A. alternata in China. The disease could infect persimmon fruits during cold storage, so more control methods should be developed to prevent postharvest disease of persimmon in the future.

Cold storage as part of a Varroa management strategy: effects on honey bee colony performance, mite levels and stress biomarkers

Placing honey bee colonies in cold storage has been proposed as a way to induce a pause in brood production as part of a Varroa mite treatment plan. Here, we exposed colonies to combinations of with or without an October cold storage period and with or without a subsequent miticide application. We then measured the effects of those treatments on colony-level variables (i.e. colony size, Varroa infestation level, survivorship and hive weight and temperature) and pooled individual-level variables that are associated with nutritional and stress responses. Colonies were assessed before and after cold storage, and again post winter, for a total duration of about 5 months, and the experiment was repeated. Brood levels were significantly lower after cold storage, and hive temperatures indicated that most or all brood had emerged after about two weeks in cold storage. However, Varroa levels at the end of the experiments in February were not significantly different among treatment groups. Colonies kept outside (not subjected to cold storage) and treated with a miticide had higher survivorship on average than any other treatment group, but no other group comparisons were significant, and long-term impact of cold storage on adult bee populations and on colony thermoregulation was low. The bee forage environment was also very different between the 2 years of the study, as rainfall and bee forage availability were much higher the second year. Colonies were over 2.5 times larger on average the second year compared to the first, both in terms of adult bee mass and brood area, and expression levels of nutrition and stress response genes were also significantly higher the second year. The results indicate that limited cold storage would likely have little long-term impact on most colony and individual measures of health, but for such a strategy to succeed levels of stressors, such as Varroa, may also need to be low.

Effects of Harvest Maturity on Storability, Ripening Dynamics, and Fruit Quality of ‘Geneva 3’ Kiwiberries

Maturity at harvest is an important determinant of fruit quality in kiwiberry [Actinidia arguta (Siebold &amp; Zucc.) Planch. ex Miq.], a climacteric fruit that is harvested after reaching physiological maturity but not yet ready-to-eat ripeness. Although a recommended cultivar for commercial kiwiberry producers in the northeastern United States is ‘Geneva 3’, no published research exists regarding recommended harvest and postharvest practices for this variety. In this study, conducted across two seasons, ‘Geneva 3’ kiwiberries were harvested at a range of mean maturities (6.5, 8.0, and 10.0°Brix), held in cold storage for various durations (4, 6, and 8 weeks), and then ripened at room temperature. At regular time points during ripening (0, 3, 6, 9, and 12 days), visual quality was assessed, and measurements were taken of soluble solids content, dry matter content, and firmness as a means of characterizing fruit quality. Results show that berries harvested at 6.5°Brix largely became visually unacceptable under cold storage conditions and resulted in lower overall quality fruit. Harvesting at 8.0°Brix resulted in high-quality fruit amenable to cold storage, and such quality was not enhanced by delaying harvest to 10.0°Brix. Fruit harvested at 8.0°Brix after 4 weeks in cold storage was found to be acceptable for consumption for, on average, a 3-day window after ripening at room temperature for 4 days. After 6 weeks in cold storage, the consumability window shortened to ∼2 days, starting after 3 days of ripening at room temperature. After 8 weeks in cold storage, the fruit were found to be largely visually unacceptable for fresh eating. In summary, the results indicate that harvesting ‘Geneva 3’ kiwiberries at 8.0°Brix produces berries with the greatest storability (at least 6 weeks in cold storage), the longest window of peak consumability, and the highest overall quality, while mitigating the risks associated with leaving physiologically mature fruit to ripen further in the field.

Biotechnological Features of a Functional Non-Dairy Mixed Juice Fermented with Lacticaseibacillus paracasei SP5

In the present study, a wild-type Lacticaseibacillus paracasei SP5 (L. paracasei SP5) potential probiotic strain (previously isolated from kefir grains) was applied for the 1-day fermentation of an apple–orange–carrot mixed juice. After the fermentation, the mixed juice was refrigerated in cold storage at 4 °C, and the microbiological stability, characterization of volatiles, physicochemical properties (pH, total titratable acidity (TTA), residual sugar content and organic acids content), the sensorial validation (aroma, taste and overall acceptability) of the juice, and the viability of the potential probiotic strain were analyzed. The stored juice exhibited zero colonies of yeasts/fungi and simultaneously the viability of L. paracasei SP5 was retained to 8.28 Log CFU/mL, even after the 4th week of cold storage. The pH values ranged from 3.80 to 3.35 and the TTA values ranged from 0.1344% to 0.1844% lactic acid for the unfermented juice up until the 4th week of cold storage. Furthermore, the organic acids content consisted mostly of lactic acid (4.6 to 9.1 g/L), while malic acid (3.7 to 1.5 g/L), acetic acid (0.6 g/L) and propionic acid (0.3 g/L) were detected only after the 4th week of cold storage. Residual sugar content ranged from the initial value of 122.2 g/L and 106.6 g/L at the end of cold storage. As far as the volatiles’ characterization is concerned: 9 esters, 2 organic acids, 12 alcohols, 3 aldehydes, 1 ketone, 6 terpenes and 4 sesquiterpenes (37 in total) were detected in the unfermented mixed juice and 33 compounds in the fermented juice after 4 weeks of cold storage. The sensorial properties (aroma, taste and overall acceptability) of the fermented mixed juice samples were positively influenced. Consequently, L. paracasei SP5 potential probiotic strain may be applied for the production of probiotic mixed juices, with satisfying viability, volatile profile and organoleptic results.

Effects of nitrite-rich and pigment-rich substitutes for sodium nitrite on the quality characteristics of emulsion-type pork sausages during cold storage

This study was conducted to evaluate the effects of nitrite-rich (celery powder; CP) and pigment-rich (purple sweet potato powder, PSP; red beet powder, RB) substitutes for synthetic sodium nitrite (CON) on the quality characteristics of emulsion-type pork sausages during four weeks of cold storage. Natural substitutes decreased the pH, lightness, and textural properties of pork sausages during storage (P < 0.05). Pigment-rich substitutes showed a decreased antioxidant effect after two weeks of storage when compared to the nitrite-rich groups (CON and CP; P < 0.05). Pigment-rich substitutes also accelerated the discoloration of pork sausages by increasing yellowness (RB and PSP) and decreasing redness (PSP) during storage (P < 0.05). However, these two pigment-rich substitutes showed different trends in redness (higher in PSP and lower in RB) and yellowness (higher in RB and lower in PSP) when compared to the nitrite-rich groups (CON and CP). Different types (nitrite-rich and pigment-rich) of natural substitutes for sodium nitrite had different effects on the quality characteristics of emulsion-type pork sausages throughout the four weeks of storage evaluated in this study.

Effects of Pomegranate Peel Extract and/or Lactic Acid as Natural Preservatives on Physicochemical, Microbiological Properties, Antioxidant Activity, and Storage Stability of Khalal Barhi Date Fruits

The use of natural preservatives in the storage of fresh fruits is a promising approach to healthier and more sustainable food processing. The current study was conducted to evaluate the effect of pomegranate peel extract (PPE) and lactic acid (LA) as natural preservatives on the shelf life of Khalal Barhi date fruits. Physicochemical properties, antioxidant activity, color parameters, texture profile, sensory characteristics, and microbiological quality of date fruits were evaluated during six weeks of cold storage (4 ± 1 °C). The bioactive compounds in PPE were determined by HPLC analysis, which showed that PPE is a rich source of bioactive compounds, particularly phenolics and flavonoids. The results exhibited decreased moisture content (from 68.36-68.43 to 62.13-63.11%) and an increased soluble solids content (from 27.16-27.24 to 31.45-33.91%) in all samples with prolonged storage. Likewise, a slight decrease in the pH (from 6.00-6.28 to 4.89-5.29) with an increase in acidity (from 0.12-0.14 to 0.23-0.27%) during storage was observed. Generally, treated samples showed lower changes in moisture content, soluble solids content, pH, and acidity than the control. A decrease in total phenolic content (TPC) (from 8.22-12.36 to 3.19-5.17 mg GAE/g) and antioxidant activity (from 44.11-68.26 to 23.84-38.52%) of all samples was observed with progressed storage, meanwhile, the treatment with PPE significantly (p < 0.05) increased TPC with a concomitant increase in antioxidant activity and maintained higher values of both throughout storage. The results exhibited a decrease in L* (from 54.87-55.92 to 41.68-45.68) and b* (from 36.25-37.09 to 23.59-25.42) values of all samples, while the a* value of all samples increased (from 1.29-1.40 to 2.22-2.43) with storage. Dipping treatment in PPE solution improved the color, exhibited the lowest change in color parameters, and maintained better texture properties during storage. Similarly, sensory properties decreased (from 8.21-8.66 to 6.71-7.21) during storage with insignificant (p > 0.05) differences among samples. Dipping treatments inhibited the growth of yeasts and molds over time, with the lowest microbial count recorded in the PPE-treated samples. It can be concluded that PPE was found to have protective effects on Khalal Barhi date fruit quality by controlling post-harvest changes and lowering the microbial load.

Fate of Listeria innocua on wax-coated Fuji apple surfaces under commercial refrigerated air storage

Wax coating is a common practice to improve glossiness, reduce water and weight loss, and extend the shelf-life of fresh apples. Apples can be contaminated with Listeria monocytogenes during waxing and other steps within preharvest and postharvest processing and handling; however, little is known about the fate of Listeria spp. on wax-coated apples during commercial cold storage. The objective of this study was to assess the fate of Listeria innocua on wax-coated Fuji apples subjected to eighteen weeks of commercial refrigerated air (RA) storage operated at 0.6 °C and ∼ 90 % relative humidity within two cropping seasons. Wax application and the subsequent 2-min drying at 22–60 °C had no impact on the fate of L. innocua and endogenous yeasts and molds on apple surfaces right after drying and over twelve weeks of cold storage. During eighteen weeks of commercial RA storage in the first cropping season, L. innocua was decreased by 1.9 log10 CFU/apple on unwaxed apples and 2.2–2.4 log10 CFU/apples on wax-coated apples at the end of storage. In the following cropping season, the fate of L. innocua on unwaxed apples was not significantly different from that of the first cropping season; there were 1.7 and 1.9–2.0 log10 CFU/apple reduction of L. innocua on unwaxed and waxed apples, respectively, at the end of eighteen weeks’ storage. Wax coating did not impact the survival of endogenous yeasts and molds on apples during eighteen weeks of commercial RA storage in both cropping seasons; there was a 0.4–0.7 log10 CFU/apple increase of yeasts and molds on unwaxed and waxed apples regardless of wax type during the storage. The application of wax coating increased the glossiness of apples and maintained apple weight and diameters but could not prevent firmness and titratable acidity loss during eighteen weeks of commercial RA storage. This study provides the apple industry with information about the behavior of Listeria on waxed fruit during commercial RA storage and highlights the need to develop alternative and effective intervention methods to control Listeria on wax-coated apples.

Gas Absorbent Based Modified Atmosphere Packaging to Optimize Dragon Fruit Shelf Life

Dragon fruit is a promising export commodity for Indonesia. But its short shelf-life is a big challenge for an international shipping by sea. This study aims to prolong the dragon fruit shelf life by implementing gas absorbent based Modified Atmosphere Packaging (MAP) in combination with cold storage. This technique decreases the fruit physiological processes by lowering O2 concentration (%) inside the MAP. The selected dragon fruit was packed with gas absorbent-based MAP with different O2 absorber capacities (30 cc; 60 cc; and 120 cc) and plastic types (biodegradable plastic and LDPE). Each treatment was also varied with the use of H2O absorbent and perforation. Then, the dragon fruit in MAP was stored at 5°C and 90% RH for 6 weeks as shipping simulation. After storage, the dragon fruit was transferred to 27°C room temperature without MAP. The results showed that the application of gas absorbent-based MAP, additional treatments, and low temperature were generally able to maintain the quality of dragon fruit up to 6 weeks in cold storage. However, dragon fruit developed signs of chilling injury, increased water loss, increased weight loss, decreased hardness, skin damage, fin withering, and mold growth after transfer at 27°C room temperature without MAP.

Market potential and value-added opportunities of cold-hardy berries and small fruits in the Intermountain West, USA.

Novel cold-hardy berries and small fruits represent an opportunity for growers in the Intermountain West, USA, as the harsh environment is not suited for other common berries and small fruits. This study analyzed the fresh market and value-added potential of haskap berries (Lonicera caerulea), saskatoon berries (Amelenchier alnifolia), and dwarf sour cherry (DSC) fruit (Prunus x kerrasis) by instrumental and consumer studies. Fresh and 2-week stored haskap (cv. Aurora), saskatoon (Lee 3), and DSC (Romeo) were measured for fruit weight, flesh firmness, bulk titratable acidity, pH, and soluble solid content. Participants (n=115) in at-home sensory tests scored these fruits for overall liking (OL, 9-point hedonic scale), purchase intent (PI, 5-point scale), and willingness-to-pay (WTP, 5-point scale). Ten participants further shared insight on these fruits in focus groups. Instrumental testing found a significant decrease in flesh firmness for 2-week stored haskap, but the consumers' OL was still comparable to fresh haskap. The fresh and 2-week stored haskap received significantly higher OL, PI, and WTP scores (7.7±1.0, 3.8±1.0, and $3.7±1.0; 7.7±1.2, 3.8±1.1, and $3.7±1.0, respectively) compared to saskatoon (6.1±1.8, 2.8±1.1, and $3.0±0.9, respectively) and DSC (5.6±2.2, 2.5±1.2, and $3.1±1.0, respectively) (α=0.05). The focus groups indicated that participants want to support local produce. The participants expressed interest in fresh unprocessed haskap berries, but preferred saskatoon and DSC in different value-added formats. Hence, this study concluded that there is an untapped fresh-market potential for haskap berries and there are value-added opportunities to extend the sale season and improve the palatability of saskatoon and DSC. PRACTICAL APPLICATION: This research has examined consumer perception of three species of novel small fruits by determining fresh-market potential and linking this to the opportunity for value-added product development. For haskap berries, the study not only indicated fresh market potential, but for the cultivar Aurora, consumer liking was not meaningfully altered by 2 weeks of cold storage. These results are meaningful because they will assist growers in the Intermountain West with market planning, including the possibility of formulating products that utilize these novel crops. This study provides growers the opportunity to diversify their income stream by utilizing local produce.