Transport & Logistics Research Center

Valencia de Alcántara, Spain

Transport & Logistics Research Center

Valencia de Alcántara, Spain

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PubMed | Transport & Logistics Research Center
Type: Journal Article | Journal: International journal of food microbiology | Year: 2012

The ability of Listeria (L.) monocytogenes to convert glucosinolates into antimicrobial isothiocyanates was investigated. Mustard glucosinolates in pure (sinigrin) or extract forms (sinigrin, oriental; sinalbin, yellow mustard) were used in broth media and in a polyvinyl polyethylene glycol graft copolymer (PPG) packaging film with bologna to examine their value as antimicrobial precursors for the control of L. monocytogenes viability and extension of bologna shelf-life at 4 C. During broth tests with deodorized (myrosinase-inactivated) mustard extracts (10 d at 20 C) or with purified sinigrin (21 d at 20 C) L. monocytogenes was only inhibited when exogenous myrosinase was added. None the less, the organism was able to hydrolyze almost half the pure sinigrin by 21 d in tests without added enzyme. Reductions in sinigrin levels were measured by reversed-phase liquid chromatography, and in the absence of L. monocytogenes or added myrosinase the glucosinolate was stable. When pure sinigrin, oriental or yellow mustard extracts were incorporated in PPG films containing 3, 5 and 6% (w/w) of the corresponding glucosinolate and used to package bologna inoculated with 4 log CFU/g L. monocytogenes, the pathogen became undetectable in bologna packed with the oriental mustard extract at 52 d storage and remained undetectable at 70 d. The yellow mustard extract was less inhibitory and the pure sinigrin was not antimicrobial. L. monocytogenes numbers reached >7 log CFU/g in the film and untreated controls at 17 d storage. At 35 d storage, samples packed with control film contained sufficient numbers of lactic acid bacteria (LAB) (>7 log CFU/g) to be considered spoiled, whereas treatments containing mustard or sinigrin remained <7 log CFU/g LAB for 70 d. L. monocytogenes played a key role in exerting control over its own viability in bologna by hydrolysis of the glucosinolate in the oriental mustard film, but other antimicrobials in treatments may have contributed.


PubMed | Transport & Logistics Research Center
Type: Journal Article | Journal: Waste management (New York, N.Y.) | Year: 2011

The use of Radio Frequency IDentification Technology (RFID) in the packaging sector is an important logistical improvement regarding the advantages offered by this technology in comparison with barcodes. Nevertheless, the presence of these devices in plastic packaging, and consequently in plastic waste, can cause several problems in the recycling plants due to the materials included in these devices. In this study, the mentioned recycling constraints have been experimentally identified in a pilot scale recycling study consisting in three recycling tests with an increasing presence of RFID tags. Differences in each test were evaluated. Furthermore, the quality of the recycled material of each test was studied through the injection and testing of tests probes. The results of the pilot scale recycling tests did not show a decrease in the quality of the recycled plastic due to the presence of RFID tags. Nevertheless, several operational problems during the recycling process were observed such as the obstruction of the screens, which lessened the process yield and created process interruptions, as well as the loss of extruded plastic during the process. These recycling constraints cannot be directly extrapolated to the industrial plants due to the different working scales. Nevertheless, technological solutions are proposed in order to avoid these recycling constraints if they appear.

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