scholarly journals Stability and Safety Assessment of Phosphorescent Oxygen Sensors for Use in Food Packaging Applications

Chemosensors ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 38 ◽  
Author(s):  
Caroline Kelly ◽  
Malco Cruz-Romero ◽  
Joseph Kerry ◽  
Dmitri Papkovsky
Keyword(s):  
Safety Assessment ◽  
Food Packaging ◽  
Oxygen Sensors ◽  
Modified Atmosphere ◽  
Atmospheric Conditions ◽  
Phosphorescence Lifetime ◽  
Optical Signals ◽  
Polypropylene Fabric ◽  
Polyphenylene Sulphide ◽  
Fabric Materials

Five types of new solid-state oxygen sensors, four based on microporous polypropylene fabric materials and one on polyphenylene sulphide films impregnated with phosphorescent platinum(II)-benzoporphyrin dye, were tested for their stability and safety in food packaging applications. All these sensors exhibit useful optical signals (phosphorescence lifetime readout) and working characteristics and are simpler and cheaper to produce and integrate into standard packaging materials than existing commercial sensors. When exposed to a panel of standard food simulants and upon direct contact with raw beef and chicken meat and cheddar cheese samples packaged under modified atmosphere, the sensors based on ungrafted polypropylene fabric, impregnated with PtBP dye by the swelling method, outperformed the other sensors. The sensors are also stable upon storage under normal atmospheric conditions for at least 12 months, without any significant changes in calibration.

scholarly journals Biocompatible Ir(III) Complexes as Oxygen Sensors for Phosphorescence Lifetime Imaging

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2898
Author(s):  
Ilya S. Kritchenkov ◽  
Anastasia I. Solomatina ◽  
Daria O. Kozina ◽  
Vitaly V. Porsev ◽  
Victor V. Sokolov ◽  
...  
Keyword(s):  
Near Infrared ◽  
Biological Systems ◽  
Aqueous Media ◽  
Oxygen Sensors ◽  
Quantum Yields ◽  
Complete Agreement ◽  
Phosphorescence Lifetime ◽  
Lifetime Imaging ◽  
Nir Emission ◽  
Phosphorescence Lifetime Imaging

Synthesis of biocompatible near infrared phosphorescent complexes and their application in bioimaging as triplet oxygen sensors in live systems are still challenging areas of organometallic chemistry. We have designed and synthetized four novel iridium [Ir(N^C)2(N^N)]+ complexes (N^C–benzothienyl-phenanthridine based cyclometalated ligand; N^N–pyridin-phenanthroimidazol diimine chelate), decorated with oligo(ethylene glycol) groups to impart these emitters’ solubility in aqueous media, biocompatibility, and to shield them from interaction with bio-environment. These substances were fully characterized using NMR spectroscopy and ESI mass-spectrometry. The complexes exhibited excitation close to the biological “window of transparency”, NIR emission at 730 nm, and quantum yields up to 12% in water. The compounds with higher degree of the chromophore shielding possess low toxicity, bleaching stability, absence of sensitivity to variations of pH, serum, and complex concentrations. The properties of these probes as oxygen sensors for biological systems have been studied by using phosphorescence lifetime imaging experiments in different cell cultures. The results showed essential lifetime response onto variations in oxygen concentration (2.0–2.3 μs under normoxia and 2.8–3.0 μs under hypoxia conditions) in complete agreement with the calibration curves obtained “in cuvette”. The data obtained indicate that these emitters can be used as semi-quantitative oxygen sensors in biological systems.

Nanocomposite Materials in Food Packaging: Opportunities, Challenges and Safety Assessment

2020 ◽  
pp. 387-397
Author(s):  
Ku Nur Izzati Ku Mohamad Faudzi ◽  
Srimala Sreekantan ◽  
Rabiatul Basria S. M. N. Mydin ◽  
Nur Afiqah Amalina Romli
Keyword(s):  
Safety Assessment ◽  
Food Packaging ◽  
Nanocomposite Materials

Pumpkin seed oil cake/polyethylene film as new food packaging material, with perspective for packing under modified atmosphere

2020 ◽  
Vol 34 (1) ◽  
pp. 25-33
Author(s):  
Senka Popović ◽  
Nevena Hromiš ◽  
Danijela Šuput ◽  
Sandra Bulut ◽  
Svetlana Vitas ◽  
...  
Keyword(s):  
Food Packaging ◽  
Seed Oil ◽  
Packaging Material ◽  
Polyethylene Film ◽  
Modified Atmosphere ◽  
Pumpkin Seed ◽  
Pumpkin Seed Oil

Effect of modified atmosphere packaging on physicochemical and microbiological characteristics of Graviera Agraphon cheese during refrigerated storage

2019 ◽  
Vol 86 (4) ◽  
pp. 483-489
Author(s):  
Nikolaos Solomakos ◽  
Maria Govari ◽  
Evropi Botsoglou ◽  
Andreana Pexara
Keyword(s):  
Foodborne Pathogens ◽  
Modified Atmosphere Packaging ◽  
Modified Atmosphere ◽  
Refrigerated Storage ◽  
Atmospheric Conditions ◽  
E Coli ◽  
Ph Values ◽  
C Storage ◽  
Microbiological Characteristics ◽  
Yeasts And Molds

AbstractThe aim of this work was to examine the effect of modified atmosphere packaging on the physicochemical and microbiological changes of Graviera Agraphon cheese during refrigerated storage. Blocks of Graviera Agraphon cheese weighing around 200 g were packaged under natural (control) or modified atmosphere packaging (MAP) conditions (50% N2 – 50% CO2) and stored at 4 °C or 10 °C for up to 85 d. Prior to packaging, groups of cheese blocks were inoculated with one each of the following foodborne pathogens at around 104 log cfu/g: Listeria monocytogenes, Salmonella Typhimurium, Escherichia coli O157:H7 or Staphylococcus aureus, whilst further groups of cheese blocks were not inoculated. The protein, fat, moisture and salt contents as well as the pH of control and MAP cheese samples did not change significantly (P > 0.05) throughout 4 °C storage, while the pH values of control and MAP cheese samples were significantly (P < 0.05) reduced at 10 °C storage. At 10 °C storage, yeasts and molds, psychrotrophs and lactic acid bacteria (LAB) were significantly higher (P < 0.05) for the normal atmosphere than the MAP cheese samples after the 4th, 8th and 4th days, respectively. At 4 °C storage, the yeasts and molds or psychrotrophs were significantly higher (P < 0.05) than those of control after the 6th and 15th days, respectively at 4 °C storage. All foodborne pathogens showed a higher decrease (P < 0.05) at 10 °C than 4 °C storage. S. aureus proved more sensitive in inactivation in the MAP conditions than atmospheric conditions. L. monocytogenes and S. aureus presented a higher decrease than that of E. coli O157:H7 and S. Typhimurium. In conclusion, MAP proved efficient in retarding the growth of yeasts, molds, psychrotrophs and E. coli O157:H7, L. monocytogenes, S. Typhimurium and S. aureus in Graviera Agraphon cheese during refrigerated storage at 4 and 10 °C.

Effect of Modified Atmosphere Packaging on the Persistence and Expression of Virulence Factors of Escherichia coli O157:H7 on Shredded Iceberg Lettuce†

2011 ◽  
Vol 74 (5) ◽  
pp. 718-726 ◽  
Author(s):  
MANAN SHARMA ◽  
SUDESNA LAKSHMAN ◽  
SEAN FERGUSON ◽  
DAVID T. INGRAM ◽  
YAGUANG LUO ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Modified Atmosphere Packaging ◽  
Ambient Air ◽  
Modified Atmosphere ◽  
Escherichia Coli O157 ◽  
Atmospheric Conditions ◽  
E Coli ◽  
Leafy Greens ◽  
Fresh Cut

Fresh-cut leafy greens contaminated with Escherichia coli O157:H7 have caused foodborne outbreaks. Packaging conditions, coupled with abusive storage temperatures of contaminated lettuce, were evaluated for their effect on the potential virulence of E. coli O157:H7. Shredded lettuce was inoculated with 5.58 and 3.98 log CFU E. coli O157:H7 per g and stored at 4 and 15°C, respectively, for up to 10 days. Lettuce was packaged under treatment A (modified atmosphere packaging conditions used for commercial fresh-cut produce, in gas-permeable film with N2), treatment B (near–ambient air atmospheric conditions in a gas-permeable film with microperforations), and treatment C (high-CO2 and low-O2 conditions in a gas-impermeable film). E. coli O157:H7 populations from each treatment were determined by enumeration of numbers on MacConkey agar containing nalidixic acid. RNA was extracted from packaged lettuce for analysis of expression of virulence factor genes stx2, eae, ehxA, iha, and rfbE. E. coli O157:H7 populations on lettuce at 4°C under all treatments decreased, but most considerably so under treatment B over 10 days. At 15°C, E. coli O157:H7 populations increased by at least 2.76 log CFU/g under all treatments. At 15°C, expression of eae and iha was significantly greater under treatment B than it was under treatments A and C on day 3. Similarly, treatment B promoted significantly higher expression of stx2, eae, ehxA, and rfbE genes on day 10, compared with treatments A and C at 15°C. Results indicate that storage under near–ambient air atmospheric conditions can promote higher expression levels of O157 virulence factors on lettuce, and could affect the severity of E. coli O157:H7 infections associated with leafy greens.

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