Comparison of Whole with Headed and Gutted Orange Roughy Stored in Ice: Sensory, Microbiology and Chemical Assessment

Sensory, microbiological and chemical analyses were used to compare whole orange roughy stored in ice with headed and gutted orange roughy stored in ice. Sensory results indicated that the whole fish had a shelf-life of 11 to 13 days. Heading and gutting gave only a slight increase in storage life. Microbiological results suggested that this increase was not due to any reduction in bacterial activity. However, chemical analyses indicated that there was reduced autolysis in the headed and gutted fish. Sulfide producing bacteria were not a significant proportion of the spoilage flora. The K value and results of analyses of inosine 5′-monophosphate and inosine were consistent with the sensory results and therefore these chemical tests are considered useful for monitoring changes in the freshness of orange roughy during ice storage.     

Determination of Postharvest Quality of Cucumbers Using Nuclear Magnetic Resonance and Electronic Nose Combined with Chemometric Methods

The purpose of this study was to investigate changes in water status and flavor characteristics of cucumbers during postharvest storage and to trace the quality attributes using partial least squares (PLS) and support vector machine (SVM). The results showed that four distinct water populations were identified in cucumbers by nuclear magnetic resonance (NMR), and the changes of water mobility and distribution occurred mainly in pulp of cucumbers. Flavor characteristics of cucumbers at different storage stages were distinguished by electronic nose (e-nose), and four clusters could be achieved through hierarchical clustering analysis. Comparison of two models, excellent prediction performances for firmness, pH, SSC, and ΔE of postharvest cucumbers were obtained using a combination method of e-nose technology and SVM algorithm. This study indicated that there were significant changes in the quality parameters of cucumbers during postharvest storage, which were related to water status and flavor characteristics. The combination of e-nose technology with the SVM algorithm offers a promising technique to monitor cucumber quality.     

Rapid Analysis of Styrene in Drinking Water and Tea Samples Using Dispersive Liquid-Liquid Microextraction Combined with Liquid Chromatography-Ultraviolet Detection

In this project, a simple, low-cost and rapid procedure based on dispersive liquid–liquid microextraction (DLLME) technique coupled with high performance liquid chromatography-ultraviolet detector (HPLC-UV) has been used for the extraction and determination of styrene in aqueous solutions. Several factors, such as type of extraction and dispersive solvents and their volumes, salt addition, and pH were optimized. Under optimal conditions, the recoveries of styrene for tea and water samples spiked with 10 and 15 ng mL^?1 were in the range of 91.4–97.8 %, whereas the temperature was set at 0, 4, 20, 70 and 91 °C for 15, 30, 60, 1440, and 14,400 min. The linear range was obtained in the interval of 1.86–50 ng mL^?1. The limits of detection (S/N = 3) and quantitation (S/N = 10) were 0.6 and 1.86 ng mL^?1, respectively. The relative standard deviations (RSDs) for three replicated analysis of styrene in aqueous samples ranged from 0.01 to 0.3 %.     

Comparison Between Sensory Quality of Freshly Prepared Spaghetti with Meat Sauce Before and After Hot Hording on a Cafeteria Counter

Sensory quality of freshly prepared spaghetti with meat sauce entree was compared to that held hot on a cafeteria counter. A study of the time and temperature relationship indicated a steady decline in temperatures during the first 30 min of steam-table holding, although within safe limits. An experienced taste panel consisting of 8–10 members rated the samples for various sensory attributes. The freshly cooked product was rated significantly higher compared to the hot-held product for moistness, appearance of spaghetti, intensity of spice flavor in the sauce, spaghetti texture, meat texture, and general acceptability.     

Comparison of Rapid Methods for Detection of Giardia spp. and Cryptosporidium spp. (Oo)cysts Using Transportable Instrumentation in a Field Deployment

Reliable, sensitive, quantitative, and mobile rapid screening methods for pathogenic organisms are not yet readily available, but would provide a great benefit to humanitarian intervention units in disaster situations. We compared three different methods (immunofluorescent microscopy, IFM; flow cytometry, FCM; polymerase chain reaction, PCR) for the rapid and quantitative detection of Giardia lamblia and Cryptosporidium parvum (oo)cysts in a field campaign. For this we deployed our mobile instrumentation and sampled canal water and vegetables during a 2 week field study in Thailand. For purification and concentrations of (oo)cysts, we used filtration and immunomagnetic separation. We were able to detect considerably high oo(cysts) concentrations (ranges: 15-855 and 0-240 oo(cysts)/liter for Giardia and Cryptosporidium, respectively) in 85 to 300 min, with FCM being fastest, followed by PCR, and IFM being slowest due to the long analysis time per sample. FCM and IFM performed consistently well, whereas PCR reactions often failed. The recovery, established by FCM, was around 30% for Giardia and 13% for Cryptosporidium (oo)cysts. It was possible to track (oo)cysts from the wastewater further downstream to irrigation waters and confirm contamination of salads and water vegetables. We believe that rapid detection, in particular FCM-based methods, can substantially help in disaster management and outbreak prevention.     

QuEChERS-Based Methods for the Determination of Pesticide Residues in a Dill Using Gas Chromatography with Electron Capture and Nitrogen Phosphorus Detection

In this study, three QuEChERS-based methods of improving sample extract preparation through reduction of unwanted matrix background for pesticide residue analysis in dill (a chlorophyll-containing matrix) were developed and compared. These methods involved the use of (1) dispersive solid-phase extraction (dispersive-SPE), (2) dispersive-SPE combined with liquid–liquid extraction (LLE), and (3) only LLE. Samples were analyzed by gas chromatography with electron capture and nitrogen phosphorus detection (GC-ECD/NPD). The results indicated that cleanup with primary secondary amine (PSA) and graphitized carbon black (GCB) sorbents followed by final solvent exchange from acetonitrile to petroleum ether was the best alternative of the tested methods, resulting in the cleanest extracts. The matrix effect of dill on the most favorable method herein was not significant, and the calibration performed well, with R ²?≥?0.99. The overall recoveries at three spiking levels of 0.01, 0.1, and 1.0 mg kg^?1 fell in the range between 73 and 110 % (95 % on average) with relative standard deviation (RSD) values equal to or lower than 12 % (5 % on average). Uncertainty for the studied pesticides ranged from 7 to 14 % (with the overall average uncertainty of 11 %). Analyses of real samples revealed the presence of pesticides unapproved for use on dill, as well as exceedances of the maximum residue levels (MRLs) for some pesticides. The samples with residue violation results were also confirmed by gas chromatography–tandem mass spectrometry (GC-MS/MS). The proposed method of sample preparation and chromatographic analysis is sufficient and can be applied with all certainty to determine pesticide residues in dill and other plants of high pigment content, i.e., chlorophyll.