Days Of Storage In Samples Research Articles

The Effect of UV-A / UV-B Radiation on Quality Changes of Harvested Curly Lettuce During the Storage

This study investigated the effects of UV-A and UV-B radiation on curly lettuce quality. Results focused on colour, total phenolic content, antioxidant activity, and ascorbic acid. The findings revealed that the highest phenolic content (46.1 mg GAE/100 g FL) had been observed in lettuce samples treated with high dose UV-B on the 7th day. The lowest phenolic content (13.7 mg GAE/100 g FL) was recorded in those treated with low dose UV-B on the same day of storage. Data showed an increase of 29.7% in antioxidant activity and 53.7% in total phenolic content after 7 days of storage in samples treated with high dose UV-B. High dose UV-A radiation was found to be the most effective in maintaining and enhancing the ascorbic acid content of the lettuce. UV applications did not cause yellowing in the stored lettuce leaves. Further research on different doses and optimization is recommended.

EP403: Finding merit in impurity: Designing a cost-effective workflow for saliva genome sequencing

Saliva is often the specimen of choice when selecting a non-invasive sample type. Properly collected, saliva is more stable and convenient to ship than blood. However, DNA extracted from saliva is notorious for its bacterial contamination, with bacterial content as high as 50% in some collections. While a high percentage of bacterial DNA may not interfere with many genetic tests, it constitutes an obstacle for genome sequencing (GS) by consuming valuable sequencing space. We aimed at designing and implementing cost-effective processes that would enable us to offer PCR-free GS using saliva-derived DNA as a clinical test. Saliva specimens were provided by volunteers from HudsonAlpha Institute of Biotechnology after written informed consent was obtained. Saliva specimens were collected with Oragene OGD-600 and OGD-675 kits (DNAgenotek). DNA was extracted with the QIAsymphony SP instrument. Libraries for PCR-free GS were generated using 0.5-1.5 μg of saliva-derived DNA with the TruSeq DNA PCR-free kit and IDT for Illumina TruSeq DNA Indices (Illumina). Sequencing was performed using the NovaSeq 6000 System, S4 flowcell, and v1.5 reagent kit. Data processing was performed with an in-house secondary pipeline that utilizes BWA-MEM (via Sentieon) for alignment, strelka2 for variant calling, and kraken2 for measuring percent human DNA versus percent bacterial contamination. Tertiary analysis was performed using an in-house tool, Codicem. Several development and optimization experiments were performed to assess: 1) input requirements for PCR-free GS from saliva-derived DNA; 2) correlation between percent aligned reads and percent human DNA; and 3) genome coverage requirements needed to accurately assess bacterial contamination. We have observed that an input of 0.5 - 1 μg can be used for saliva-derived DNA, consistent with inputs for blood-derived DNA. We also found that an initial low coverage run (1X) for saliva-derived DNA could be used to estimate bacterial contamination of a sample, and our analysis pipeline was able to accurately estimate percent human DNA at a coverage as low as 0.5X. The percent aligned reads differed largely between individuals due to high variability in bacterial DNA contamination. As expected, percent aligned reads correlated with percent human DNA (R2=0.998). The estimation of bacterial content could then be used to facilitate the most efficient sample processing by informing the amount of library required to achieve the desired coverage. We further investigated whether a different collection method of saliva allowed us to improve sequencing efficiency. A sponge collection kit (OGD-675) showed a substantial reduction in bacterial contamination with increase in percent human DNA and percent reads aligned compared to a spit collection kit (OGD-600). On average, human DNA content was 95.44% in sponge kits compared to 85.15% in spit kits. Furthermore, the distribution of percent aligned reads in GS data obtained from saliva specimens collected with sponge kits was much narrower than that for the samples collected with the spit kit (99.46-83.47% compared to 97.09-46.44%). Despite smaller collection volumes in sponge kits and subsequent lower total DNA yields (average of 7.8 μg in sponge kits compared to 12 μg in spit kits), we observed DNA amounts extracted from sponge kits to be sufficient for primary and confirmatory testing. A supplementary stability study performed using DNA isolated 0 and 31 days after collection showed that bacterial contamination did not significantly increase over time for either sponge or spit collection kits (average increase from 3.01% to 3.56% in sponge kits and from 10.27% to 12.31% in spit kits). However, we noted that percentage aligned reads decreased more during the 30 days of storage in samples with high bacterial contamination at initial extraction, with up to 8% increase in bacterial contamination observed for samples with initial human DNA content less than 60%. Consequently, we observed a narrower distribution of percentage aligned read changes over time in DNA isolated from the sponge collection kits (0.01-1.58% compared to 0.1-8.8%). HudsonAlpha Clinical Services Lab has validated PCR-free GS assay with saliva-derived DNA as an input. The workflow efficiency is increased due to the implementation of a preliminary sequencing to 1X coverage as a method to estimate bacterial contamination. This step allows us to triage samples and eliminate failures due to insufficient coverage, as well as balance sequencing pools to achieve desired coverage. As a result of our studies, we found that a sponge saliva collection kit provides sufficient DNA yields with relatively low bacterial contamination, making the sponge kit the preferred collection method for GS applications.

Evaluating the effect of an emerging microwave-assisted induction heating (MAIH) on the quality and shelf life of prepackaged Pacific white shrimp Litopenaeus vannamei stored at 4°C in Taiwan

Microwave-assisted induction heating (MAIH) is an emerging alternative technology for shrimp cooking over traditional heating technologies. This study evaluated the effect of the MAIH and boiling in salt solution on the quality and shelf life of prepackaged Pacific white shrimp L . vannamei stored at 4 °C in Taiwan. Samples were treated for 80 s at 130 °C or for 100 s at 90 °C with the MAIH technology, and 130 s at 90 °C with boiling in salt solution, respectively. Cooked shrimps were stored 28 days at 4 °C to determine changes in aerobic plate count (APC), psychrotrophic bacteria count (PBC), color, texture, pH, and total volatile basic nitrogen (TVBN). Results showed that the levels of APC and PBC were not detectable (<2.0 log CFU/g) during first 12 days of storage in samples treated with the MAIH technology, but they slowly increased afterward, reaching to 3.0 log CFU/g on the 28th day of storage, compared to the traditional boiling technology, when the levels of APC and PBC were gradually increased throughout 28 days of storage, exceeding 8.7 log CFU/g at the end of the storage. In terms of color and TVBN, all cooked samples showed a decreasing trend in lightness ( L* ), redness ( a* ), and whiteness ( W ) but an increasing trend in yellowness ( b* ), absolute color difference ( ΔE ), and the TVBN during the storage period. However, these decreasing and increasing trends occurred slower in samples treated by the MAIH than by boiling ( p < 0.05). In terms of texture, samples treated by the MAIH demonstrated greater hardness and cohesiveness during the storage than samples boiled in salt solution ( p < 0.05). Compared with traditional boiling method, the treatment of shrimp samples with the MAIH delayed the degradation of color and texture and inhibited the growth of microorganisms during refrigerated storage. Therefore, the MAIH technology offers a potential alternative over boiling method for preventing the deterioration and quality loss of shrimps more effectively and extending the refrigerated shelf life of prepackaged Pacific white shrimps stored at 4 °C. • Effect of MAIH and boiled heating on quality of shrimp stored at 4 °C were evaluated. • The MAIH effectively pasteurized and retarded bacterial growth of shrimp until 12 d. • The boiled samples had higher aerobic plate counts and lower physicochemical values. • MAIH can delay reduction of color ( L* , a* , W ) and hardness in samples during storage. . • Shrimps heated by MAIH maintained lower TVBN and extended shelf life from 8 d to 28 d .

THE EFFECT OF TEMPERATURE AND TIME ON THE MIGRATION OF LEAD METAL (PB) IONS IN CANNED ORANGE JUICE DRINK USING ATOMIC ABSORPTION SPECTROPHOTOMETRY ANALYSIS

Background: Indonesia is a country that has a tropical climate throughout the year along with relatively less difference of temperature during both dry and rainy seasons. The mobile community influences people’s interest in packaged drinks, including canned fruit juice. However, the first obstacle is the condition of the place and the temperature-related heavy metal lead (Pb) migration in canned orange juice drinks. Methods: This study focused on the relationship between Pb metal content, storage treatment, storage temperature, and storage time. This study used a canned orange juice drink from the distributor warehouse of Palembang city, standard Pb(NO3)2 (Merck) powder, 0.5 mol/l concentrated HNO3 solutions (Merck), concentrated HCl solution (Merck), demineralized water, Buffer pH 4.7, and 10. The sample was conducted from 5 °C to 40 °C with the testing period within 1-30 days. The sample at certain day intervals would then be tested to change pH and Pb ion concentration using the Atomic Absorption Spectrophotometry (AAS) test. Results and Discussion: In this study, the sample of orange juice was given different treatments, and each treatment has a differentiated analysis code consisting of S-SBJ-1-1 (Distributor warehouse) for one day of storage time, and the codes for 10 of storage time are SSBJ-10-1 (Freezer, temperature 5 °C), S-SJB-10-2 (Refrigerator, temperature 20 °C), S-SJB-10-3 (Homeroom, temperature 28 °C), S-SJB-10-4 (Oven, temperature 40 °C), S-SJB-10-5 (Open space, temperature 22°C - 38 °C). Furthermore, codes for 30 days of sample storage are S-SBJ-30-1 (Freezer, temperature 5 °C), S-SJB-30-2 (Refrigerator, temperature 20 °C), S-SJB-30-3 (Room house, temperature 28 °C, S-SJB-30-4 (Oven, temperature 40°C), and S-SJB-30-5 (Open space, temperature 22 °C-38 °C). Conclusions: Temperature and time have a significant influence on the migration of the heavy metal lead (Pb) from the can to orange juice drinks, and, for the minimum pH value, there is a less significant change. Overall, canned fruit juice should be stored at a temperature below 28 °C, and the drink is protected from direct sunlight and high humidity.

Long-term surface modification of PEEK polymer using plasma and PEG silane treatment

Despite the several advantages of the Polyetheretherketone (PEEK) polymer, its wide application is limited due to its hydrophobic nature and poor surface adhesion performance. The plasma treatment can effectively transform the hydrophobic surface to hydrophilic. However, their effects are for a short duration, and the modified surfaces gradually lose their wetting and surface adhesion properties. In this work, we have reported a combined effect of plasma and PEG Silane treatment for permanent hydrophilic modification and improved adhesion strength of PEEK surfaces. The time-dependent changes in the contact angles, XPS, and ATR-FTIR spectra results were carefully recorded to investigate the surface properties of the modified surfaces. It was observed that the functional groups and polar component of surface energy played a pivotal role in long-term modification of PEEK surfaces. The Plasma and PEG Silane treated PEEK surface retained a very low contact angle and high content of hydroxide, carboxylic acid, and peroxide groups as compared to the plasma-treated PEEK surfaces. The lap shear test confirms the long-term effects of Plasma and PEG Silane treatment on adhesion properties with high bonding strength after 48 days of sample storage, which was dropped for Plasma treated surface just after 7 days of storage.

Stability of interleukin-1β, -4, -6, -8, -10, -13, interferon-γ and tumor necrosis factor-α in human sera after repetitive freeze-thaw cycles and long storage

IntroductionCytokines (CKs) are one of the key components of the molecular network modulating multiple immunological interactions. Within such biological systems, CKs functions are associated with several processes, thus quantification of these analytes in serum samples, as well as a faithful determination of its concentration, are crucial for the translational aspect of many studies. AimThis study is focused on the evaluation of the effects of storage duration and multiple freeze-thaw cycles on CKs stability. Materials and methodsSerum samples were obtained from 24 healthy participants. Samples were prospectively stored at 4 °C for 1–7 and 30 days, and also underwent multiple freeze-thaw cycles. Afterwards, CK levels were determined by enzyme-linked immunosorbent assay. ResultsAmong the 8 examined CKs all of them showed significant degradation (determined with the two-way ANOVA and post-hoc test) after 4 days of sample storage at 4 °C. Serum were affected by freezing at −20 °C and thawing, and 2 of CKs (IL-1β and IL-8) showed significant concentration decrease after following 2 freeze-thaw cycles. It has been also determineded that CKs in serum samples after multiple freeze-thaw cycles had better stability, when samples were stored at −80 °C (compared to storage at −20 °C). ConclusionsThis study demonstrates that long storage at 4 °C, as well as multiple freeze-thaw cycles of serum samples, must be avoided and CK concentrations should be measured immediately after sample collection.

Blood Serum Stability Limit and Maximum Storage Time of Bovine Samples

Background: Measuring metabolic parameters in the blood has been an indispensable tool for assessing the productive and health status of dairy cows for more than 100 years. The values of laboratory parameters depend on various preanalytical, analytical and postanalytical factors. The most important preanalytical factors are sample transport time and temperature, hemolysis, anticoagulant type, and sample volume.Preanalytical factors can lead to reduced stability of the analyte in the sample, which changes their concentration. Loss of stability changes the time of storage and manipulation of the sample, which determines the criteria for its acceptance or rejection. The two stability indicators are stability limit and maximum permissible instability. A stability limit (SL) is defined as the period of time in which a property variation does not exceed a maximum permissible instability (MPI). The aim of this study was to determine the SL and MPI for each analyte in the blood serum of cows and to determine whether SL differs in the function of the presence of preanalytical errors in the blood sample.Materials, Methods &amp; Results: Three hundred samples of dairy cow origin in different periods of lactation participated in this research. They were classified into 6 groups of 50 samples: according to the time from sampling to processing in the laboratory (0-4 h, 4-8 h and over 8 h; all transported on dry ice, protected from environmental factors, without preanalytical errors) and according to the presence of preanalytical errors (group with hemolysis, a group transported at ambient temperature and a group with a small sample volume). Each sample was aliquoted in two portions. One portion was left at +4°C and tested once a day for 6 days of sample storage, and the second portion, placed at -20 °C, was tested once a month for 6 months. The MPI had a value ranging from 1.55 to 8.4. Metabolic profile analytes with lower MPI values (1.51-3.22) were albumin (ALB), total protein (TPROT), UREA, glucose (GLU), calcium (Ca), and phosphorus (P). Higher MPI values (5.1-8.3) were found for nonesterified fatty acids (NEFA), beta-hydroxybutirate (BHB), cholesterol (CHOL), triglycerides (TGC), total bilirubin (TBIL) and aspartat aminotransferase (AST). For most parameters, we can conclude that their PD% changed faster in storage conditions at +4 °C compared to the regime of -20 °C. The largest number of biochemical analytes in bovine blood serum shows preserved stability in the first 6 days at +4°C or 6 months at -20°C if transported to the laboratory within 8 h after sampling in ideal conditions and without the action of preanalytical errors. Prolonged transport under ideal conditions or the existence of preanalytical errors such as transport at room temperature, hemolysis or small sample volume shorten the stability of the ALB, NEFA, GLU, UREA and P. Concentration of all analytesdecreasesduring the stability test except for UREA, NEFA, BHB and for CHOL and TGC in some groups. Variations in parameters such as BHB, NEFA, TBIL, AST, and Ca have shown potential clinical significance. At storage conditions at +4°C, clinically significant variations at at least one measurement point were found for AST (7.5% of samples), BHB (6.1% of samples), NEFA (9.9% of samples) and for TBIL (in 7% of samples).Discussion: This study can help define acceptable delay times and storage conditions for bovine blood samples, which is of great importance because in working with farm animals it is often not possible to take samples in a short time and deliver them to the laboratory, and samples are often burdened with certain preanalytical errors with limited possibilities of re-sampling.

1540 nm LIBS Investigation of Healthy and Pathological Human Nails

The paper discusses the possibility of using laser-induced breakdown spectroscopy (LIBS) as a method for the diagnosis of human nail onychomycosis. LIBS spectra obtained with excitation of plasma on the surface of healthy and onychomycotic nails by pulses of Q switched Yb, Er: Glass laser radiation with a wavelength of 1540 nm were compared for the first time. The spectrum of onychomycotic nail contained unique lines additional to characteristic spectral lines of healthy nails. These additional lines disappeared after 90 days of sample storage in air at room temperature 20 ± 3 °C.

Effects of temperature and storage time on the motility, viability, DNA integrity and apoptosis of processed human spermatozoa.

The aim of this study was to evaluate motility, viability, DNA integrity and apoptosis of spermatozoa when washed semen samples were kept for up to 12days at 4-6°C and 25°C. In this experimental study, 26 normozoospermic semen samples were washed twice in Modified Ham's F10 and resuspended in IVF fertilisation medium. Half of the specimens were stored at 4-6°C, and the other half was kept at 25°C for 12days. The proportions of viable, motile, spermatozoa with double-stranded DNA and apoptotic spermatozoa were examined during storage time. Apoptosis was measured using annexin V-PI staining followed by flow cytometry. Results showed that sperm motility and viability decreased during 12days of sample storage (p<.001). There was no significant difference between the two temperatures in terms of motility and viability for up to 2days (p<.05). The percentage of spermatozoa with double-stranded DNA remained unchanged during the 12days of storage at both temperatures (p>.05). Although there was no difference between the two temperatures in terms of motility, viability and apoptosis during the first two days of storage, storage of spermatozoa at 4-6°C is better than storage for a longer period than storage at 25°C. Sperm DNA resisted against denaturation during storage.

Oxidative stability of lipid fractions of sponge-fat cakes after green tea extracts application

Oxidative stability of lipid fractions extracted from sponge-fat cakes enriched with green tea extracts and synthetic antioxidant (BHA) directly after baking and after 28 days of storage was investigated. This was achieved by the determination of peroxide (PV), p-anisidine (p-AnV) and acid values (AV), and using Rancimat test or differential scanning calorimetry method, respectively. The results showed that the lipid fractions extracted from sponge-fat cakes containing the addition of BHA (0.02%) and green tea extract at concentrations of 1% exhibited a greater resistance to oxidation than those from cakes without additives. AV values were the lowest for lipids extracted from sponge-fat cakes enriched with 1% green tea extract up to the end of storage. The incorporation of BHA and green tea extract (1%) into cakes caused a gradual increase of PV and p-AnV values during 21 days of sample storage. The values of these parameters increased significantly for samples without any additives, especially in regard to PV. What is more, thermal analysis showed that samples enriched with 1% green tea extract and with BHA were characterized by higher onset temperature (tON), activation energy, and induction time (τ) than samples without any additives, especially during 21 days of storage. The increase of green tea extract concentration to 1% in cookies reduced L* (from 63.85 to 51.15) and b* (from 34.64 to 29.11) values, while a* value showed an increase from 8.43 to 11.17.

High Pressure Homogenization of Porcine Pepsin Protease: Effects on Enzyme Activity, Stability, Milk Coagulation Profile and Gel Development.

This study investigated the effect of high pressure homogenization (HPH) (up to 190 MPa) on porcine pepsin (proteolytic and milk-clotting activities), and the consequences of using the processed enzyme in milk coagulation and gel formation (rheological profile, proteolysis, syneresis, and microstructure). Although the proteolytic activity (PA) was not altered immediately after the HPH process, it reduced during enzyme storage, with a 5% decrease after 60 days of storage for samples obtained with the enzyme processed at 50, 100 and 150 MPa. HPH increased the milk-clotting activity (MCA) of the enzyme processed at 150 MPa, being 15% higher than the MCA of non-processed samples after 60 days of storage. The enzyme processed at 150 MPa produced faster aggregation and a more consistent milk gel (G’ value 92% higher after 90 minutes) when compared with the non-processed enzyme. In addition, the gels produced with the enzyme processed at 150 MPa showed greater syneresis after 40 minutes of coagulation (forming a more compact protein network) and lower porosity (evidenced by confocal microscopy). These effects on the milk gel can be associated with the increment in MCA and reduction in PA caused by the effects of HPH on pepsin during storage. According to the results, HPH stands out as a process capable of changing the proteolytic characteristics of porcine pepsin, with improvements on the milk coagulation step and gel characteristics. Therefore, the porcine pepsin submitted to HPH process can be a suitable alternative for the production of cheese.

Changes in the fatty acid profile of intramuscular fat in goose meat packed in different atmospheres

Summary Atmosphere type and storage time had significant effects on the fatty acid (FA) profile of goose breast muscle lipid. The FA profile did not change during 14 days of storage in muscle packed in vacuum. The percent of saturated FA (SFA) and monounsaturated FA (MUFA) increased gradually during 14 days of storage in samples packed in modified atmosphere, whereas the level of polyunsaturated FA (PUFA) decreased in the same period. The muscle packed in vacuum were characterised by a higher PUFA/SFA ratio and greater PUFA content concerning n-3 FA after storage in comparison to the samples packed in modified atmosphere (MA).

AVALIAÇÃO PRELIMINAR DA ESTABILIDADE DE EMULSÕES NÃO IÔNICAS CONTENDO ÁCIDO KÓJICO A 2,0 % MANIPULADAS EM FARMÁCIAS MAGISTRAIS

Formulações emulsionadas contendo ácido kójico são comuns entre os produtos cosméticos para clareamento cutâneo. Neste trabalho, avaliou-se a estabilidade preliminar de loções não iônicas contendo ácido kójico a 2,0 %, manipuladas em farmácias magistrais. As formulações foram adquiridas em 04 estabelecimentos farmacêuticos do município de Porto Alegre-RS. As amostras, em frascos de polietileno, foram submetidas à estocagem a 25 e 45ºC e analisadas nos tempos zero, 7, 15, 30 e 60 dias. As amostras foram avaliadas através das seguintes determinações: características organolépticas, pH, teste de centrifugação e determinação de peso da embalagem. Os caracteres organolépticos se apresentaram com modificações a partir de 7 dias de estocagem, em amostras a 45 ºC. Quanto ao pH, as amostras a 45 ºC apresentaram redução do valor inicial, com acréscimo de acidez ao longo do tempo. Neste caso, a centrifugação das amostras não provocou modificação no parâmetro avaliado, nem levou à separação de fases. Para a determinação de peso, os resultados ilustraram uma leve modificação no peso das amostras estocadas a 45 ºC, ilustrando a necessidade de atenção para o material de acondicionamento. Os ensaios desenvolvidos reforçam a importância de atenção na estabilidade de produtos cosméticos contendo ácido kójico, em especial no conhecimento da base galênica e no armazenamento do produto.

Effect of disinfection and storage on the flexural strength of ocular prosthetic acrylic resins

To evaluate the influence of chemical disinfection and storage duration on the flexural strength of acrylic resins commonly used to make ocular prostheses. A total of 260 samples were manufactured with N1 resin and colourless resin. Both resins were thermopolymerised using a microwave oven. Samples were stored and periodically disinfected and were divided into groups: control (no disinfection) (I), neutral soap (II), Opti-free (III), Efferdent (IV), 1% hypochlorite (V) or 4% chlorhexidine (VI). The flexural strength was measured before and after 60 and 120 days of storage. Data were analysed by anova and Tukey test (0.05). The flexural strength of the N1 resin was higher than that for the colourless resin. There was a significant difference in the flexural strength before and after 60 and 120 days of storage with disinfection, regardless of the resin and disinfectant. Group I in the initial period exhibited greater flexural strength, with significant difference only in group VI after 120 days. It can be concluded that the flexural strength only changed after 120 days of storage for samples disinfected with chlorhexidine. However, all flexural strength values obtained herein were acceptable clinical limits for the acrylic resins.

EFFECT OF COSMOS CAUDATUS, POLYGONUM MINUS AND BHT ON PHYSICAL PROPERTIES, OXIDATIVE PROCESS, AND MICROBIOLOGY GROWTH OF QUAIL MEATBALL DURING REFRIGERATION STORAGES

ABSTRACT Cosmos caudatus ([CC]/ulam raja), Polygonum minus ([PM]/kesum) extracts and butylated hydroxyanisole (BHT) were evaluated to examine the effects of physical properties, pH, thiobarbituric acid (TBA), free fatty acid (FFA), peroxide value (PV) and microbial growth in a quail meatball during 21 days of storage. No significant difference in physical properties and pH was observed. The TBA, FFA and PV after 21 days of storage in samples formulated with CC, PM and BHT were lower compared with control. The TBA, FFA and PV were 0.137 mg MA/kg, 3.93%/g, and 4.02 meq/kg sample, respectively, in the sample formulated with CC and 0.132 mg MA/kg, 3.84%/gr, and 4.31 meq/kg sample, respectively, in the PM. The addition of CC, PM and BHT significantly reduced the aerobic plate count. This study shows that CC and PM are potential sources of natural antioxidants that have similar characteristics as the synthetic antioxidant BHT. PRACTICAL APPLICATIONS In recent years, natural antioxidants have increasingly replaced artificial preservatives in food products. Natural antioxidants like Cosmos caudatus and Polygonum minus have many of the same functions as artificial antioxidants like butylated hydroxyanisole; they can increase the shelf life of stored products without affecting other qualities that are important to consumers. This research explores the effects of natural antioxidants on quality changes of quail meatball during refrigeration storage.

PACKAGING TECHNOLOGY INFLUENCE ON THE SHELF LIFE EXTENSION OF FRESH RASPBERRIES

Raspberries have been classified as a non-climacteric fruit - they have high physiological post-harvest activity, short ripening and a senescence period. The objective of this study was to examine the possibility of shelf life extension of primocane raspberry cultivar 'Polana' by packaging in different materials. The experiments were performed in the Latvia University of Agriculture Faculty of Food Technology, Jelgava and in the Latvia State Institute of Fruit Growing, Dobele during the year 2007. Contents of ascorbic acid, anthocyanins, color in the L * a * b * measuring system, changes of moisture content and pH were analyzed during the storage period of three weeks. Oxygen and carbon dioxide dynamics in hermetic packages were analyzed by gas analyzer. The effect of packaging materials for shelf life extension was determined by using different packages: PP (polypropylene) trays inserted in pouches made from PLA (polylactic acid) films of different thickness 25 and 40 μm; cardboard boxes placed in PLA film pouches of different thickness 25 and 40. PP boxes manufactured with holes and cardboard boxes covered with net were used as control packaging in the experiments. The content of vitamin C rapidly increased during the first two days of storage in samples of all packaging materials but after four days ascorbic acid content started to decrease. The influence of packaging materials on the ascorbic acid content of raspberry samples was not significant. The anthocyanin content of all samples packaged in PLA material was quite stable during the whole storage time. The lowest weight losses were obtained in the PLA-40-PP sample (2.6%) although the other packaged samples did not exceed 5.2%. All samples placed in PLA (polylactic acid) film pouches by thickness 25 μm had optimal gasses composition (10 to 20% CO 2 and 5 to 10% O 2 ) for storage of primocane raspberry cultivar 'Polana'.

Comparison of different application strategies of divergicin M35 for inactivation of Listeria monocytogenes in cold-smoked wild salmon

Cold-smoked salmon treated with divergicin M35-producing Carnobacterium divergens M35, C. divergens ATCC 35677 (a non-producer of bacteriocin), purified divergicin M35 or supernatants of C. divergens M35 culture in snow crab hepatopancreas (SCH) medium or MRS broth was challenged with Listeria monocytogenes (up to 10 3 CFU/g). Samples were stored at 4 °C for up to four weeks. L. monocytogenes, total bacterial and lactic acid bacterial counts were determined along with changes in total volatile base nitrogen (TVBN) and biogenic amine production as well as texture, color and odor. A 2.6 log CFU/g reduction in L. monocytogenes was obtained for up to 10 days of storage in samples treated with C. divergens M35. Purified divergicin M35 (50 μg/g), SCH supernatant or MRS supernatant brought reductions of 1 log CFU/g at the beginning of storage. However, the anti-listerial activity of the supernatants lasted for 15 days compared to 3 days for purified divergicin M35. Color and texture were affected little in samples containing C. divergens M35 compared to un-inoculated samples. TVBN and biogenic amine production, particularly tyramine, remained below the maximum acceptable level in fish appreciation. These results clearly show the potential of C. divergens M35 culture as well as divergicin M35 bio-ingredient for application to the inactivation of L. monocytogenes in ready-to-eat seafood.

A time‐resolved immunofluorometric assay for porcine C‐reactive protein quantification in whole blood

A time-resolved immunofluorometric assay (TR-IFMA) for C-reactive protein (CRP) determination in whole blood of pigs was developed and validated. CRP was isolated from porcine acute-phase serum by affinity chromatography on agarose, coupled with phosphorylethanolamine and polyclonal antibodies to porcine CRP were purified from antiserum raised in sheep immunized with porcine CRP. Intra- and inter-assay coefficients of variation (CVs) were in the range 3.13-7.19% and 7.06-15.66%, respectively, showing good precision. The assay measured the CRP values in a proportional and linear manner (r=0.99); additionally, CRP concentrations measured in whole blood by the present TR-IFMA and in serum by an established immunoturbidimetric assay were highly correlated (R(2)=0.97). The limit of detection of the method was 0.0028 mg/L. Significantly lower CRP concentrations were observed after 7 days of sample storage at 4 degrees C. The injection of turpentine oil caused a significant increase in CRP concentrations and significantly higher CRP concentrations were observed in pigs with pathological processes compared to healthy animals.

Real-time quantitative reverse transcription-PCR for cyclin D1 mRNA in blood, marrow, and tissue specimens for diagnosis of mantle cell lymphoma.

Overexpression of cyclin D1 mRNA, found in mantle cell lymphoma (MCL), is a critical diagnostic marker. We investigated the use of real-time reverse transcription-PCR (RT-PCR) for cyclin D1. We studied 97 fresh specimens (50 blood, 30 bone marrow, 15 lymph node, and 2 other samples) from patients diagnosed with a variety of lymphoproliferative diseases, including 25 cases of MCL. We used real-time quantitative RT-PCR to evaluate cyclin D1 mRNA expression. Because blood and marrow specimens may contain only a minority of potentially malignant cells (as opposed to most lymph nodes) and to increase sensitivity, we normalized the cyclin D1 mRNA concentrations to mRNA of a B-cell-specific marker, CD19, as well as to previously characterized beta(2)-microglobulin mRNA. In 16 of 21 cases of MCL with overt disease, the ratio of cyclin D1 mRNA to beta(2)-microglobulin mRNA was increased, but all 21 cases showed increased ratios of cyclin D1 mRNA to CD19 mRNA. Cyclin D1 mRNA was low or undetectable in various lymphoproliferative diseases, including cases of ambiguous immunophenotype. The mRNA ratios were stable over 3-7 days of sample storage. Quantitative RT-PCR for cyclin D1 mRNA normalized to CD19 mRNA can be used in the diagnosis of MCL in blood, marrow, and tissue.

Control of Listeria monocytogenes with Combined Antimicrobials after Postprocess Contamination and Extended Storage of Frankfurters at 4° C in Vacuum Packages

Contamination of ready-to-eat foods, such as frankfurters, with Listeria monocytogenes, is a major concern that needs to be addressed in order to enhance the safety of these products. The objective of this study was to determine the effectiveness of combinations of antimicrobials included in the formulation of frankfurters against L. monocytogenes inoculated (103 to 104 CFU/cm2) on their surface after peeling and before vacuum packaging. In addition, the antilisterial effect of immersing the packaged products, prepared with or without antimicrobials, in hot (75 or 80°C) water for 30 to 90 s was evaluated. Samples were stored at 4°C for up to 120 days and periodically analyzed for pH and for microbial growth on tryptic soy agar plus 0.6% yeast extract (TSAYE) and PALCAM agar. Sodium lactate (1.8%; 3% of a 60% commercial solution) used alone inhibited growth of L. monocytogenes for 35 to 50 days, whereas when used in combination with 0.25% sodium acetate, sodium diacetate, or glucono-δ-lactone (GDL), sodium lactate inhibited growth throughout storage (120 days). Immersing packaged frankfurters in hot water (80°C, 60 s) reduced inoculated populations of L. monocytogenes by 0.4 to 0.9 log CFU/cm2 and reduced its growth by 1.1 to 1.4 log CFU/cm2 at 50 to 70 days of storage in samples containing 1.8% sodium lactate alone. However, immersion of frankfurters containing no antimicrobials in hot water (75 or 80°C) did not inhibit growth of the pathogen for more than 10 to 20 days, unless one frankfurter was placed per bag and heat treated for 90 s. These results indicate that the inclusion of 1.8% sodium lactate with 0.25% sodium acetate, sodium diacetate, or GDL in cured meat formulations may control L. monocytogenes growth during refrigerated (4°C) storage. Additional studies are required to evaluate the effects of these combinations at abusive temperatures of storage, as well as on additional processed meat formulations and on the sensory quality and shelf life of products.