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Shelf-life
Kinds of Shelf-life Selected AbstractsUSING GELATIN-BASED ANTIMICROBIAL EDIBLE COATING TO PROLONG SHELF-LIFE OF TILAPIA FILLETSJOURNAL OF FOOD QUALITY, Issue 3 2002CHAN-YIN OU Skinless tilapia (Dreochromis niloticus x D. aureus) fillets were covered with a gelatin coating containing benzoic acid as an antimicrobial agent. Benzoic acid content of fish fillets was used to estimate the amount of gelatin coated on fillet surface, and it was found that the gelatin contents were between 16.3 mg and 17.3 mg per g of fillets. Aerobic and anaerobic microbial loads, volatile basic nitrogen (VBN) contents, and sensory evaluation were used as indicators to survey the feasibility of an antimicrobial gelatin coating to prolong the shelf-life of tilapia fillets under refrigeration. After 7 days of storage under refrigeration, tilapia fillets coated with gelatin containing benzoic acid had acceptable VBN contents, increased moderately in microbial loads, and showed no significant sensory difference (P < 0.05) from fresh fillets. The results indicate that an antimicrobial gelatin coating is suitable for preservation of tilapia fillets. [source] EFFECTIVENESS OF CHLORINE AND NISIN-EDTA TREATMENTS OF WHOLE MELONS AND FRESH-CUT PIECES FOR REDUCING NATIVE MICROFLORA AND EXTENDING SHELF-LIFE,JOURNAL OF FOOD SAFETY, Issue 4 2002DIKE O. UKUKU ABSTRACT Efficacy of nisin-EDTA treatments as a sanitizing treatment for reducing native microflora of whole melons and extending shelf-life of fresh-cut pieces was compared to chlorine treatments. Whole cantaloupe and honeydew melons were washed with water, nisin (10 ,g/mL)-EDTA (0.02 M), or 200 ppm chlorine for 5 min at , 20C before fresh-cut preparation and storage at 5C for 15 days with periodic microbiological sampling. In addition, some fresh-cut pieces were washed with 10 ,g/mL nisin-EDTA or 50 ppm chlorine for 1 min before storage. Changes in appearance, odor, overall acceptability and the shelf-life of the minimally processed fresh-cut melons were investigated. Preliminary studies indicated that water washes, EDTA (0.002 to 0.2 M) or nisin (5 to 10 ,g/mL) were not effective in reducing the microflora of whole melon when used individually. Nisin-EDTA and chlorine treatments were significantly (P < 0.05) more effective in reducing native microflora than water washes. Nisin-EDTA treatments were significantly (P < 0.05) more effective than chlorine in reducing populations of yeast and mold and Pseudomonas spp. on whole melon surfaces but were not as effective as chlorine treatments for reducing aerobic mesophilic bacteria, lactic acid bacteria and total gram-negative bacteria. Microbial contaminants on fresh-cut pieces washed with 50 ppm chlorine or nisin-EDTA were further reduced. However, microbial populations increased throughout refrigerated storage irrespective of treatments. Odor, appearance, and overall acceptability ratings for cantaloupe and honeydew fresh-cut pieces treated with nisin-EDTA or chlorine were not significantly (P > 0.05) different from each other throughout the storage period (15 to 21 days). However, both treatments led to significantly (P < 0.05) improved ratings compared to the controls for the fresh-cut pieces at 9 to 12 days of storage and thereafter. The results of this study suggest that treatments with nisin-EDTA before and after fresh-cut processing would improve the quality and extend the shelf-life of fresh-cut melon. [source] INFLUENCE OF HAZELNUT PASTE ON THE SENSORY PROPERTIES AND SHELF-LIFE OF DARK CHOCOLATEJOURNAL OF SENSORY STUDIES, Issue 2 2004L.A. NATTRESS ABSTRACT The addition of hazelnut paste to dark chocolate formulations altered the sensory profile. The flavors chocolate, burnt, rancid, hazelnut, green and metallic, and the texture attributes hardness, graininess, consistency of melt, viscosity and onset of melt determined by descriptive analysis were significantly (P < 0.05) influenced by the addition of up to 10% hazelnut paste. The shelf-life of dark chocolates containing hazelnut exceeded 10 months. The textural attributes of hardness, consistency of melt and onset of melt were highly correlated to instrumental measurements. [source] Retail Shelf-Life of Pork Dipped in Organic Acid before Modified Atmosphere or Vacuum PackagingJOURNAL OF FOOD SCIENCE, Issue 8 2005Nai-Yun Huang ABSTRACT Modified atmosphere packaging (MAP) is increasingly popular for meat, but raw, chilled pork in vacuum or anoxic environments has a purple color. The retail shelf-life of pork chops dipped in 500 ppm ascorbic acid, 250 ppm citric acid, or no acid dip and stored at 1 °C before simulated retail display in MAP with gas exchange or air-permeable packaging after vacuum pouch storage was determined. The 80% N2:20% CO2 in MAP was exchanged with 80% O2:20% CO2, and chops were removed from vacuum packages and overwrapped with permeable film (VP-PVC) on the 7th day before simulated retail display at 4 °C. Shelf-life traits were determined at 1, 7, 8, 10, 12, and 14 d postpackaging. The pH values changed with time, but returned to post-dipped, prepackaged levels at the end of simulated retail storage. Weight loss of chops increased (P < 0.05) in VP-PVC compared with MAP. The a* values increased (P < 0.05) and L* and b* values decreased during simulated retail display, with higher L*, a*, and b* color values for chops in MAP than VP-PVC. Log numbers of psychrotrophic microorganisms were higher (P < 0.05) on VP-PVC samples than for chops in MAP on days 12 and 14. Psychrotrophic counts on ascorbic acid-treated samples were decreased compared with citric acid or no dipping on pork during simulated retail display. Pork chops in MAP with gas exchange had lighter and redder color, increased weight retention, decreased psychrotrophic counts, and increased lipid oxidation compared with conventional vacuum and overwrap packaging systems. [source] Effects of high-pressure processing on Listeria monocytogenes, spoilage microflora and multiple compound quality indices in chilled cold-smoked salmonJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2004R. Lakshmanan Abstract Aims:, To evaluate the effect of high-pressure processing (HPP) on Listeria monocytogenes, microbial and chemical changes and shelf-life in chilled cold-smoked salmon (CSS). Methods and Results:, First, challenge tests with L. monocytogenes were carried out using HPP of the product at 0·1 (control), 150, 200 and 250 MPa. Secondly, storage trials with the naturally contaminated product and HPP at 0·1 (control) and 200 MPa were realized. Shelf-life, microbial changes and chemical changes were determined and existing predictive models and multiple compound quality indices evaluated. HPP with 250 MPa did not inactivate L. monocytogenes but significant lag phases of 17 and 10 days were observed at ca 5 and 10°C, respectively. HPP with 200 MPa had a marked effect on both colour and texture of CSS. Conclusions:, High-pressure processing was unable to prevent growth of L. monocytogenes or spoilage of chilled CSS. Existing mathematical models allowed growth rates of L. monocytogenes and shelf-life of samples without high-pressure treatments to be predicted. Significance and Impact of the Study:, High-pressure processing seems more appropriate for new types of salmon products than for a classical product like CSS where consumers expect specific quality attributes. [source] SENSORY ANALYSIS AND STORAGE STABILITY OF FLAVORED SOYBEAN SPREADS PRODUCED FROM HOT-GROUND SOYMILK,JOURNAL OF FOOD QUALITY, Issue 2 2002K.A. KHATIB Flavored and unflavored soybean spreads were produced from a soybean variety low in beany off-flavors. The stability of the spreads was evaluated by chemical, physical, and microbiological tests over 35 days at 4C and 50% RH. Descriptive, focus group and consumer acceptance analyses were also conducted. Spreads were rated for degrees of beany flavor, aroma, and aftertaste. Total plate and psychrotrophic counts increased during storage, but no syneresis nor coliforms were detected over the storage period for either flavored or unflavored spreads. No significant treatment by day interactions were noted among pH, moisture content, water activity, lightness, and saturation index of spreads. Flavored spreads scored 6.2 on a 9-point hedonic scale and were more accepted by consumers than unflavored spreads. Shelf-life of flavored and unflavored soybean spreads was estimated to be 28 days at 4C. [source] Effect of Plasticizer Concentration and Solvent Types on Shelf-life of Eggs Coated with ChitosanJOURNAL OF FOOD SCIENCE, Issue 4 2006Su Hyun Kim ABSTRACT:, Effects of plasticizer concentrations (0, 0.5, 1.0, 1.5, and 2.0% glycerol) and solvent types (1% acetic and 1% lactic acid) on internal quality of eggs coated with 2% chitosan solution were evaluated during 5 wk of storage at 25 °C. In comparison of plasticizer concentrations, eggs coated with chitosan dissolved in acetic acid containing 2% glycerol showed significant reduction in weight loss compared with the noncoated eggs during 5 wk of storage. At 2% glycerol, the Haugh unit and yolk index values suggested that chitosan-coated eggs can be preserved for at least 3 wk longer than the control noncoated eggs during 5 wk of storage at 25 °C. Use of acetic acid rather than lactic acid as a chitosan solvent was more advantageous in view of shelf-life extension of eggs. [source] Development of emulsion from rhizobial fermented starch industry wastewater for application as Medicago sativa seed coatENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2010Rojan Pappy John Abstract Starch industry wastewater was efficiently employed for the production of Sinorhizobium meliloti and the concentrated culture was used for the development of a biofertilizer formulation. Tween-80 (0.02,g/L) acted as the best emulsifier for a Sinorhizobium,canola oil emulsion. The stability of the emulsion and survival of the organism was enhanced by supplementation of xanthan gum at pH 8. The refrigerated condition was most favorable for stability and survival of the microorganism. The survival of microorganism at 4±1°C was 2.78×1010 and 2.01×1010,CFU (colony forming unit)/mL on storage for 1 and 2 months, respectively. The values were higher than the prescribed cell count (×103,CFU/mL) for field application. At 40°C, the survival of bacteria reduced from 3×1010,CFU/mL to 8.1×109 and 8.8×106,CFU/mL in 1 and 2 months, respectively. Emulsion-coated seed was incubated at different temperatures and a cell count of 105,CFU/seed was observed after 2 months of storage at 4°C, which was equal to the highest level of the described requirement (103,105,CFU/seed). Emulsion supplemented with xanthan gum improved the shelf-life under optimized conditions (Sinorhizobium concentrate,,,canola oil (1:1) emulsion with 0.02,g/L Tween-80; storage at pH 8 and temperature 4±1°C) and this emulsion with the required cell count and prolonged viability was used for the pre-inoculation of seed or for in situ soil application. [source] Coffee ,avour: an overviewFLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2004Roberto A. Buffo Abstract This paper is a concise review of the research on coffee ,avour to serve as a rapid reference on the subject. It covers the process of roasting coffee beans, the volatile and non-volatile components generated by the process and the chemical reactions responsible for their formation. Volatile compounds signi,cant on the determination of coffee aroma are given according to the most recent research. Finally, the paper discusses the chemical indexes used over the years to characterize coffee ,avour deterioration and estimation of shelf-life. Copyright © 2004 John Wiley & Sons, Ltd. [source] Low-Temperature Solution-Processed Memory Transistors Based on Zinc Oxide NanoparticlesADVANCED MATERIALS, Issue 30 2009Hendrik Faber We report on thin!film transistors based on ZnO nanoparticles processed from solution and with a maximum temperature of 100,°C. Electron mobilities up to 2.5,cm2V,1s,1 are obtained, and top-gate TFTs show non-volatile memory properties with a large, stable hysteresis and a memory ratio of 105. Memory TFTs operate in ambient, have good shelf-life (>6 months), and useful endurance properties. [source] Novel Structural Modulation in Ceramic Sensors Via Redox Processing in Gas BuffersINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 3 2006Abdul-Majeed Azad High selectivity, enhanced sensitivity, short response time, and long shelf-life are some of the key features sought in the solid-state ceramic-based chemical sensors. As the sensing mechanism and catalytic activity are predominantly surface-dominated, benign surface features in terms of small grain size, large surface area, high aspect ratio and, open and connected porosity, are required to realize a successful material. In order to incorporate these morphological features, a technique based on rigorous thermodynamic consideration of the metal/metal oxide coexistence is described. By modulating the oxygen partial pressure across the equilibrium M/MO proximity line, formation and growth of new oxide surface on an atomic/submolecular level under conditions of "oxygen deprivation," with exotic morphological features, has been achieved in potential sensor materials. This paper describes the methodology and discusses the results obtained in the case of potential semiconducting ceramic oxide-based carbon monoxide and hydrogen sensors with enhanced characteristics. [source] Original article: Effect of modified atmosphere packaging using different CO2 and N2 combinations on physical, chemical, microbiological and sensory changes of fresh sea bass (Dicentrarchus labrax) filletsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2010Laura Provincial Summary The effect of different modified atmosphere packaging (MAPs) on physical, chemical, microbiological and sensory changes of sea bass fillets when stored at 4 °C and standard light conditions was investigated for up to 21 days and compared to a control batch stored in overwrap. Sea bass fillets were packed using different CO2 and N2 combinations (40% CO2,60% N2; 50% CO2,50% N2; 60% CO2,40% N2), and quality assessment was based on instrumental, chemical, microbiological and sensory analysis. The results showed that MAP extended shelf-life of sea bass fillets from 7 days (overwrap packaging) to 14 days. Drip loss, pH values and thiobarbituric acid reactive substances (TBARS) measurements were higher in overwrap samples but no differences (P , 0.05) were found between MAP samples. Bacteria grew most quickly and showed higher counts in overwrap samples followed by 40% CO2,60% N2; 50% CO2,50% N2 and finally 60% CO2,40% N2. Sensory analyses were in good relation with chemical and microbiological results establishing best scores and an extended shelf-life for MAP samples especially in MAPs with high CO2 levels. [source] The effects of soluble gas stabilisation on the quality of packed sardine fillets (Sardina pilchardus) stored in air, VP and MAPINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 11 2008Rogério Mendes Summary Sardine (Sardina pilchardus) is a species that for its abundance assumes great importance in the Portuguese fishing sector. In order to contribute for a better utilisation of this species, the aim of this study was to investigate the effect of the pre-treatment with soluble gas stabilisation (SGS) (100% CO2 at 2 bar, during 15 and 30 min) on the quality and shelf-life of sardine fillets, packed in air (AP), vacuum (VP) and modified atmosphere (MAP: 5% O2/35% CO2/60% N2). During the chilled storage, the quality changes were evaluated by sensory evaluation, chemical and microbiological analysis. The total volatile basic nitrogen content remained almost constant, between 16 and 19 mg N/100 g muscle, during the storage period, for all samples. The TBARs values increased with storage time, for all batches and storage conditions. The application of SGS treatment to sardine fillets, resulted in a bacteriostatic effect, contributing to the improvement of the microbiological quality of fillets. Considering a sensory criteria, the shelf-life of SGS pre-treated sardine fillets was found to be 5 days in AP and MAP while in VP-treated fillets a shelf-life of 8 days was reported. At sensory rejection, sardine fillets presented a K -value of 30% in AP and MAP batches and 40% in VP batch. [source] Effect of temperature and initial moisture content on sorption isotherms of banana dried by tunnel drierINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2008Zhengyong Yan Summary Sorption isotherms of intermediate moisture content (IMC) products are essential to predict shelf-life of packaged moisture-sensitive product by modelling moisture uptake during storage and distribution. The effect of temperature and initial moisture content (MC) of IMC banana on the relationship between MC and water activity were investigated. Raw bananas were dried in a tunnel dryer at 2% relative humidity (RH), 70 °C, and a 3.2 ± 0.2 m s,1 air velocity. Drying procedure was carried out a number of times until various IMC levels were obtained (5%, 14%, 22% and 33% db for banana). Sorption isotherms of bananas were determined at 10, 20, 30 and 40 °C. The initial MC of IMC banana had no significant effect on the relationship between MC and water activity according to statistical analysis. All the sorption curves were found to be Type II. BET, GAB, modified GAB, Oswin, Halsey and modified Freundlich models were fitted to the data and it was found that the best results were obtained with a modified Freundlich equation. A secondary modified Freundlich model was built accounting for the effect of aw and temperature on the sample MC. [source] Prevalence and characterisation of Bacillus cereus in vacuum packed potato pureeINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2006Andreja Rajkovic Summary Refrigerated processed foods of extended durability (REPFED) potato puree was analysed for Bacillus cereus contamination along the production line and during the product shelf-life. Isolated B. cereus strains were tested for their psychrotrophic character and the ability to produce enterotoxins. Bacillus cereus contamination during four subsequent productions was in the range of 2.3,4.0 log cfu g,1. Productions five and six were significantly less contaminated with B. cereus (,1 log cfu g ,1). All B. cereus isolates from the first four productions were able to grow at 7 ° and 10 °C, whereas the majority of the isolates from productions five and six did not. No B. cereus isolates grew at 4 °C. randomly amplified polymorphic DNA (RAPD) fingerprinting showed that the most of B. cereus contamination originated from one source. In total, 30.4% of isolates expressed enterotoxic character. The present study points out the necessity to prevent an ,in house' colonisation and contamination during food processing in order to accomplish the safety of REPFED throughout the shelf-life. It also indicates the most critical steps in the production line of ready-to-eat potato puree and impact of failures regarding the food safety. The data provided can be used for risk assessment studies regarding B. cereus in REPFED. [source] Preparation of tofu using chitosan as a coagulant for improved shelf-lifeINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2004Hong Kyoon No Summary The potential of chitosan as a coagulant in commercial tofu preparation was investigated with six chitosans of different molecular weights using various treatments. The following optimum processing conditions for tofu preparation were proposed: chitosan with a molecular weight of 28 kDa; chitosan solution type, 1% chitosan/1% acetic acid; chitosan solution to soymilk ratio, 1 : 8; coagulation temperature, 80 °C; coagulation time, 15 min. However, the sensory quality of tofu was notably improved using a 1 : 1 mixture of 1% acetic acid and 1% lactic acid instead of 1% acetic acid alone as a chitosan solvent. Tofu prepared with chitosan had lower ash and higher protein content than those of commercial products tested. In storage tests, the chitosan-tofu had a longer shelf-life, about 3 days, than tofu made with CaCl2. This added shelf-life is significant in view of the magnitude (366 000 tonnes year,1) of tofu produced from commercial tofu plants (1407 plants as of 1998) in Korea. [source] The effects on the quality of Cavendish bananas, which have been treated with ethylene, of exposure to 1-methylcyclopropeneINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2003N. Bagnato Summary After 48 h of ethylene treatment (300 ,L L,1), to induce ripening of mature, green bananas (Musa sp., AAA type, Cavendish subgroup, cv. Williams), fruit were exposed to 0 (control), 3, 300 nL L,1, or 30 ,L L,1 1-methylcyclopropene (1-MCP) for 24, 48 or 72 h at 20 °C. Bananas treated with 300 nL L,1 1-MCP had a 6-day shelf-life compared with 3 days for non-treated fruit, and 4 days for fruit treated with 3 nL L,1 1-MCP. Increased shelf-life (half-ripe to over-ripe) occurred without affecting the green life (unripe to half-ripe) of bananas, peel appearance, pulp texture, soluble solid concentrations or aroma profiles. Fruit treated with 30 ,L L,1 were externally and internally commercially unacceptable, as fruit developed crown rot prior to ripening. Application of 1-MCP at suitable concentrations could extend banana shelf-life, by enhancing marketing and consumer expectations without compromising banana quality. [source] Effects of CO2 absorbent and high-pressure treatment on the shelf-life of packaged Kimchi productsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2003Joo W. Lee Summary The effects on extending the shelf-life of commercial Kimchi products and preventing pouch inflation by absorbing CO2 with calcium hydroxide, were compared with a treatment using high-hydrostatic pressure. The changes in the quality factors of Kimchi, such as CO2 accumulation in the headspace of the pouch, pH, total acidity and the microbial population of both total viable cells and lactic acid bacteria were measured during storage for 24 days at 10 °C. Pressurization at 400 and 600 MPa for 5 min at 20 °C were both effective in preventing inflation of the Kimchi pouches during storage at 10 °C, as was CO2 absorption at the level of 0.5 g CO2 absorbent per 80 g Kimchi. [source] A review of modified atmosphere packaging of fish and fishery products , significance of microbial growth, activities and safetyINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2002Morten Sivertsvik Modified atmosphere packaging (MAP) extends shelf-life of most fishery products by inhibiting bacterial growth and oxidative reactions. The achievable extension of shelf-life depends on species, fat content, initial microbial population, gas mixture, the ratio of gas volume to product volume, and most importantly, storage temperature. The shelf-life of fishery products is usually limited by microbial activity, although for some fatty fishes or at superchilled storage, it can be limited by nonmicrobial activity. Packaging of fishery products under modified atmospheres (MA) increases shelf-life compared with those packaged under air, but confers little or no additional shelf-life increase compared with vacuum packaging. The specific spoilage organism (SSO) of MA packaged cod at 0 °C has been found to be Photobacterium phosphoreum. Whether or not this bacterium is the general SSO for all marine temperate fishes at different storage temperatures and under various CO2/N2/O2 mixtures needs to be resolved. Without proper control of storage temperature, the benefits of MAP may be lost. Higher temperatures inevitably lead to less dissolved CO2 in the product and consequently loss of inhibitory effect, which may result in higher microbial and enzymatic activity, and uncertainties concerning the microbial safety, as food-borne pathogens might be present in the product. [source] Comparison of different methods of bacterial detection in blood componentsISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2009M. Schmidt Background, Over the last two decades, the residual risk of acquiring a transfusion-transmitted viral infection has been reduced to less than 1 : 1 000 000 via improvements in different techniques (e.g. donor selection, leuco-depletion, introduction of 3rd or 4th generation enzyme-linked immunosorbent assays and mini-pool nucleic acid testing (MP-NAT). In contrast, the risk for transfusion-associated bacterial infections has remained fairly stable, and is estimated to be in a range between 1 : 2000 and 1 : 3000. Platelets are at an especially higher risk for bacterial contamination, because they are stored at room temperature, which provides good culture conditions for a broad range of bacterial strains. To improve bacterial safety of blood products, different detection systems have been developed that can be divided into culture systems like BacT/ALERT or Pall eBDS, rapid detection systems like NAT systems, immunoassays and systems based on the FACS technique. Culture systems are used for routine bacterial screening of platelets in many countries, whereas rapid detection systems so far are mainly used in experimental spiking studies. Nevertheless, pathogen-reduction systems are currently available for platelet concentrates and plasma, and are under investigation for erythrocytes. Methods, In this review, the functional principles of the different assays are described and discussed with regard to their analytical sensitivity, analytical specificity, diagnostic sensitivity, diagnostic specificity and clinical efficiency. The detection methods were clustered into three groups: (i) detection systems currently used for routine screening of blood products, (ii) experimental detection systems ready to use for routine screening of blood products, and (iii) new experimental detection systems that need to be investigated in additional spiking studies and clinical trials. Results, A recent International Society of Blood Transfusion international forum reported on bacterial detection methods in 12 countries. Eight countries have implemented BacT/ALERT into blood donor screening, whereas in three countries only quality controls were done by culture methods. In one country, shelf-life was reduced to 3 days, so no bacterial screening was implemented. Screening data with culture methods can be used to investigate the prevalence of bacterial contamination in platelets. Differing results between the countries could be explained by different test definitions and different test strategies. Nevertheless, false-negative results causing severe transfusion-related septic reactions have been reported all over the world due to a residual risk of sample errors. Rapid screening systems NAT and FACS assays have improved over the last few years and are now ready to be implemented in routine screening. Non-specific amplification in NAT can be prevented by pre-treatment with Sau3AI, filtration of NAT reagents, or reduction of the number of polymerase chain reaction cycles. FACS systems offer easy fully automated handling and a handling time of only 5 min, which could be an option for re-testing day-5 platelets. New screening approaches like immunoassays, detection of bacterial adenosine triphosphate, or detection of esterase activity need to be investigated in additional studies. Conclusion, Bacterial screening of blood products, especially platelets, can be done with a broad range of technologies. The ideal system should be able to detect one colony-forming unit per blood bag without a delay in the release process. Currently, we are far away from such an ideal screening system. Nevertheless, pathogen-inactivation systems are available, but a system for all blood components will not be expected in the next few years. Therefore, existing culture systems should be complemented by rapid systems like NAT or FACS especially for day-5 platelets. [source] Whey-cheese production using freeze-dried kefir culture as a starterJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2007D. Dimitrellou Abstract Aims:, The aim of the present study was to evaluate the use of a freeze-dried kefir culture in the production of a novel type of whey-cheese similar to traditional Greek Myzithra-cheese, to achieve improvement of the quality characteristics of the final product and the extension of shelf-life. Methods and Results:, The use of kefir culture as a starter led to increased lactic acid concentrations and decreased pH values in the final product compared with whey-cheese without starter culture. The effect of the starter culture on production of aroma-related compounds responsible for cheese flavour was also studied using the solid phase microextraction gas chromatography/mass spectrometry technique. Spoilage in unsalted kefir-whey-cheese was observed on the thirteenth and the twentieth day of preservation at 10 and 5°C, respectively, while the corresponding times for unsalted whey-cheese preservation were 11 and 14 days. Conclusions:, The cheeses produced were characterized as high-quality products during the preliminary sensory evaluation. An indication of increased preservation time was attributed to the freeze-dried kefir culture, which also seemed to suppress growth of pathogens. Significance and Impact of the Study:, The results suggested the use of kefir culture as a means to extend the shelf-life of dairy products with reduced or no salt content. [source] Effects of high-pressure processing on Listeria monocytogenes, spoilage microflora and multiple compound quality indices in chilled cold-smoked salmonJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2004R. Lakshmanan Abstract Aims:, To evaluate the effect of high-pressure processing (HPP) on Listeria monocytogenes, microbial and chemical changes and shelf-life in chilled cold-smoked salmon (CSS). Methods and Results:, First, challenge tests with L. monocytogenes were carried out using HPP of the product at 0·1 (control), 150, 200 and 250 MPa. Secondly, storage trials with the naturally contaminated product and HPP at 0·1 (control) and 200 MPa were realized. Shelf-life, microbial changes and chemical changes were determined and existing predictive models and multiple compound quality indices evaluated. HPP with 250 MPa did not inactivate L. monocytogenes but significant lag phases of 17 and 10 days were observed at ca 5 and 10°C, respectively. HPP with 200 MPa had a marked effect on both colour and texture of CSS. Conclusions:, High-pressure processing was unable to prevent growth of L. monocytogenes or spoilage of chilled CSS. Existing mathematical models allowed growth rates of L. monocytogenes and shelf-life of samples without high-pressure treatments to be predicted. Significance and Impact of the Study:, High-pressure processing seems more appropriate for new types of salmon products than for a classical product like CSS where consumers expect specific quality attributes. [source] Hybrid modeling of inulinase bio-production processJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2010Marcio A. Mazutti Abstract BACKGROUND: A potential application of inulinase in the food industry is the production of fructooligosaccharides (FOS) through transfructosilation of sucrose. Besides their ability to increase the shelf-life and flavor of many products, FOS have many interesting functional properties. The use of an industrial medium may represent a good, cost-effective alternative to produce inulinase, since the activity of the enzyme produced may be improved or at least remain the same compared with that obtained using a synthetic medium. Thus, inulinase production for use in FOS synthesis is of considerable scientific and technological appeal, as is the development of a reliable mathematical model of the process. This paper describes a hybrid neural network approach to model inulinase production in a batch bioreactor using agroindustrial residues as substrate. The hybrid modeling makes use of a series artificial neural network to estimate the kinetic parameters of the process and the mass balance as constitutive equations. RESULTS: The proposed model was shown to be capable of describing the complex behavior of inulinase production employing agroindustrial residues as substrate, so that the mathematical framework developed is a useful tool for simulation of this process. CONCLUSION: The hybrid neural network model developed was shown to be an interesting alternative to estimate model parameters since complete elucidation of the phenomena and mechanisms involved in the fermentation is not required owing to the black-box nature of the ANN used as parameter estimator. Copyright © 2010 Society of Chemical Industry [source] Accelerated stability model for predicting shelf-lifeJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 5 2002Robert T. Magari Abstract Second- and higher-order degradation reactions sometimes cannot be approximated with linear or exponential relationships and need to be appropriately modeled. Events above the COULTER® HmX Analyzer white blood cell (WBC) counting threshold were recorded for the HmX PAK reagent system stored at five elevated temperatures. An accelerated stability model for a second-degree polynomial degradation pattern was used. The shelf-life of the reagent, along with 95% lower bound confidence intervals, is predicted using the same pattern of degradation as well as the Arrhenius approximation. Experiments indicated that the degradation of the HmX PAK reagent occurred in two phases, the lag phase and the degradation phase, in all tested temperatures. The phase durations are temperature-dependent, and the Arrhenius approximation is appropriate (P=0.639). The degradation of the reagent during the lag phase was experimentally undetectable. Changes of the reagent were nonsignificant for a predicted period of 164 days at 25°C. The rate of degradation increased significantly later on during the degradation phase. The lower bound of the 95% confidence interval of this prediction indicated that it would take at least 326 days before the HmX PAK reagent would have any performance issue related to aging at storage temperature. J. Clin. Lab. Anal. 16:221,226, 2002. © 2002 Wiley-Liss, Inc. [source] INVOLVEMENT OF PEROXIDASE AND POLYPHENOL OXIDASE IN MANGO SAP-INJURYJOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2002K. SABY JOHN ABSTRACT Sap (latex) that oozes out from mango during harvest, upon contact with the fruit, causes dark spots (sap-injury) on the peel and reduces consumer acceptance and shelf-life of fruit. In this investigation different components responsible for sap-injury were identified. Mango saps from four Indian varieties were collected and separated into aqueous and nonaqueous phases. Whole sap, aqueous phase and nonaqueous phase were tested for their ability to cause sap-injury (browning) on mangoes. The nonaqueous phase caused maximum injury and the extent of injury caused by nonaqueous phases from different varieties was varied. Limonene, ocimene and ,-myrcene, the major terpenoids identified in saps of Indian varieties, caused injury. Similar type of injury on mangoes was also caused by organic solvents. Damage on Totapuri mango fruit was significantly lower compared to other varieties, whereas Totapuri nonaqueous phase caused injury on all other varieties. The peel of Totapuri variety had very low level of polyphenol oxidase, peroxidase and polyphenols compared to other varieties. Thus, a clear relation was found between the peel polyphenol oxidase, peroxidase activities, the polyphenol content in the peel and the extent of injury. Further, nonaqueous phase applied on peels previously heat-treated at 95C for 5 min, neither caused injury nor showed any enzyme activity. Thus, the results indicated that the terpenoid components of sap and polyphenol oxidase, peroxidase, polyphenols of peel are involved in sap-injury. [source] EFFECT OF GLYCEROL ON PHYSICAL PROPERTIES OF CASSAVA STARCH FILMSJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2010P. BERGO ABSTRACT In this work, the effect of glycerol on the physical properties of edible films were identified by X-ray diffraction (XRD), differential scanning calorimetry (DSC), infrared (FTIR) and microwave spectroscopy. According to XRD diffractograms, films with 0 and 15% glycerol displayed an amorphous character, and a tendency to semicrystallization, for films with 30% and 45% glycerol. From DSC thermograms, the glass transition (Tg) of the films decreased with glycerol content. However, two Tgs were observed for samples with 30% and 45% glycerol, due to a phase separation. The intensity and positions of the peaks in FTIR fingerprint region presented slight variations due to new interactions arising between glycerol and biopolymer. Microwave measurements were sensitive to moisture content in the films, due to hydrophilic nature of the glycerol. The effect of plasticizer plays, then, an important rule on the physical and functional properties of these films, for applications in food technology. PRACTICAL APPLICATIONS Edible and/or biodegradable films are thin materials used mainly in food recovering, food packaging and other applications, in substitution of the films obtained by synthetic ways. In view of these applications, these films must satisfy some of the exigencies in order to increase the food shelf-life, or in other words, they must be flexible, transparent, resistant to some gases such as oxygen, as well as resistant to water vapor. The addition of plasticizers alters the functional properties of the films. Thus, the physical characterization of these films becomes fundamental in order to increase their potential use in industry. [source] MATHEMATICAL MODELLING OF THIN-LAYER DRYING OF KIWIFRUIT SLICESJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2009M DOYMAZ ABSTRACT The effect of temperature on the drying kinetics of kiwifruit was investigated. The drying process was carried out at temperatures of 50, 55 and 60C, air velocity of 2.4 m/s and relative humidity between 10,25%. Drying time decreased considerably with increased air temperature. Drying process took place in the falling rate period. Twelve mathematical models available in the literature were fitted to the experimental data. The models were compared by four statistical parameters; i.e., determination of coefficient, mean relative percent error, reduced chi-square and root mean square error, and the best-fit model was selected. The modified Henderson and Pabis and Verma et al. models were given the best results in describing thin-layer drying of kiwifruits. The effective diffusivity of water during air-drying varied from 1.743 to 2.241 × 10,10 m2/s over the temperature range investigated, with activation energy equal to 22.48 kJ/mol. PRACTICAL APPLICATIONS Drying can be described as an industrial preservation method in which water content and activity of agricultural products are decreased by heated air to minimize biochemical, chemical and microbiological deterioration. Kiwifruit has a very short life because of softening and vitamin loss during cold storage. The use of drying prolongs the shelf-life of the kiwifruit, as the water content reduction slows down deterioration reactions. In this study, drying characteristics of kiwifruits were studied in a convectional hot-air dryer. The objectives of the present study were to determine experimentally the thin-layer drying characteristics and rehydration capacity of samples, and to fit the experimental data to 12 mathematical models available from the literature. [source] STORAGE QUALITY OF PASTEURIZED AND UV TREATED APPLE CIDERJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2003KAWALJIT TANDON Two studies were conducted to assess the effect of hot-fill pasteurization at 63C and UV irradiation at 14 mJ/cm2 on the quality and shelf-life of apple cider packaged under controlled conditions with minimal packaging contamination, and under pilot plant conditions resembling commercial operations. The processed cider was stored at 7C for up to 14 weeks in the first study and 4 weeks in the second. Microbiological, chemical and sensory tests were conducted weekly on cider samples. There were no significant differences among the fresh processed ciders with regard to taste and preference. All treatments achieved a reasonable reduction in microbial counts, although hot-fill pasteurization provided longer shelf-life. There were significant changes in pH, titratable acidity, soluble solids and turbidity of samples during storage. Hot-fill at 63C is a comparable alternative to flash pasteurization at 71C for 6 s for the production of safe quality cider at small cider mills. [source] DESIGN, CONSTRUCTION AND VALIDATION OF A SANITARY GLOVE BOX PACKAGING SYSTEM FOR PRODUCT SHELF-LIFE STUDIESJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2001ZEHRA AYHAN A glove box has been constructed as pan of an integrated pilot plant scale pulsed electric field processing and packaging system to facilitate studies of product shelf-life with selected packaging materials. The glove box was sanitized using combination of hydrogen peroxide and germicidal UV light. A HEPA air filter provided positive pressure of bacteria-free air. Nonselective nutrient broth was sterilized and filled into presanitized bottles inside the glove box. Negative and positive controls were included in the experiment. All bottles were incubated at 22C and 37C for two weeks and checked for rnicrobial growth by measuring optical density at 600 nm using a spectrophotometer and by plating on plate count agar and potato dextrose agar for total aerobic and, yeast and mold counts, respectively. No turbidity or microbial growth was observed in the media filled in the sanitized bottles using the sanitized glove box at 22 and 37C. PEF processed orange juice using this system had a shelf-life of more than 16 weeks at 4C. [source] THE EFFECT of MODIFIED ATMOSPHERE PACKAGING ON the MICROBIAL ECOLOGY IN REQUEIJÃO, A PORTUGUESE WHEY CHEESEJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2000MANUELA E. PINTADO The effects of modified atmosphere packaging on growth of adventitious microorganisms in Portuguese whey cheese (Requeijão) were studied following a response surface methodology using storage time (2, 6, 10 and 15 days), storage temperature (4, 12 and 18C) and fraction of CO2 in the overhead gaseous mixture also containing nitrogen (0, 50 and 100%) as manipulated variables. the viable numbers of Enterobacteriacea, staphylococci, yeasts and spore-forming bacteria in the experimental whey cheeses did not increase within 15 days when storage was at 4C under 100% CO2; those of enterococci increased significantly after 6 days under similar conditions, and a similar inhibiting effect was observed against Bacillus, pseudomonads, lactobacilli and streptococci. It was observed that 100% N2 at 4C was able to completely inhibit growth of staphylococci, lactobacilli and Bacillus for 2 days. the loci (and the nature) of the optima in terms of manipulated variables were obtained for all microbial groups studied. No true overall minimum was found, but storage conditions preset at 4C and 100% CO2 led to a 15 day extension of the shelf-life of Requeijão. [source] | |||||||||||||||||||