Gli autori desiderano ringraziare tutti gli studenti del laboratorio di sicurezza alimentare e volontari che hanno contribuito con questo studio. Questa ricerca è stata finanziata da una sovvenzione Initiative USDA Nazionale Integrato per la sicurezza alimentare (NIFSI) (Award # 10.507.316).

1. Curva standard <ol><li> Pesare polvere fluorescente 37,5 mg e sciogliere in 6 ml 200 di etanolo prova. Effettuare diluizioni seriali 2-fold di questa soluzione a 200 di etanolo prova. </li><li> Vortex tutti i campioni per 10 secondi e misurare l&#39;assorbanza a 370 nm. </li><li> Calcolare la quantità di polvere fluorescente per 1 ml 200 prova etanolo. </li><li> Preparare la curva standard (concentrazione in mg / ml su l&#39;asse y e l&#39;assorbanza a 370 nm sul asse x) per dimostrare l&#39;assorbanza basata sulla concentrazione polvere fluorescente. </li></ol> 2. Seminare Deli Meat (Bologna) con polvere fluorescente <ol><li> Tagliare la carne deli in circa 100 millimetri campioni di spessore con un coltello pulito e tagliere. Preparare tre campioni etichettati A, B, e C. </li><li> Cappotto campione A uniformemente con polvere fluorescente con una leggermente umido, spugna pulita. Stendere la polvere sul campione di carne in modo uniforme. Non inoculare i campioni B e C con la polvere fluorescente. </li&gt; <li> Avvolgere i campioni con pellicola trasparente e etichettare il campione verniciato a polvere fluorescente come &#39;A&#39; e rimanendo due campioni come B e C con nastro adesivo. </li><li> Posizionare i campioni nel caso deli o frigorifero tenutasi a 4 ° C in cucina, finto, dove verrà effettuata l&#39;esperimento. </li></ol> 3. Mock Deli Cucina Preparazione <ol><li> Fornire guanti puliti e il 70% di etanolo spruzzo in cucina. </li><li> Montare lampade fluorescenti compatte nere con 13 W lampadine intorno alla zona affettatrice. </li><li> Preparare un cm ritaglio di foglio di alluminio 5 cm x 5 per servire come modello per tampone. </li><li> Preparare 15 ml provette contenenti 6 ml di etanolo al 95%. </li></ol> 4. Setup Video Mount tre telecamere in punti strategici per osservare tutte le aree del deli finto allo stesso tempo. Accendere le telecamere prima simulando la procedura affettatrice (come spiegato nel protocollo 5) e analizzare i risultati contemporaneamente (comespiegato nel protocollo 7). 5. Simulazione di procedure Deli Slicing nella pista Croce contaminazione Al fine di migliorare la dimensione del campione e incorporare variazione, eseguire questo studio reclutando i partecipanti dopo l&#39;approvazione del protocollo da parte del Consiglio della rispettiva istituzione Institutional Review. Il partecipante può essere uno studente universitario che possono o non possono avere esperienza di lavoro in ambienti deli al dettaglio. Assicurarsi che ogni partecipante porta i guanti una volta entrati la gastronomia. Prendete un &quot;prima&quot; immagine sotto la luce fluorescente nera seguita da un &quot;dopo&quot; immagine al termine dello studio. Fornire chiare istruzioni scritte e verbali ad ogni partecipante come segue: <ol><li> Vai al frigorifero. </li><li> Togliere la carne etichettata &quot;A&quot;. </li><li> Scartare la carne e salvare l&#39;involucro di plastica. </li><li> Mettere la carne sul vassoio trasporto di affettatrice. </li><li> Fissare la carne con impugnatura carne. </li><li> Accendere l&#39;interruttore di alimentazione su ON. </li><li> Regolare slimanopola indice cer a &quot;2&quot;. </li><li> Slice e dispensare 5 pezzi di carne su carta deli. </li><li> Accendere l&#39;interruttore di alimentazione su OFF e rilasciare la presa di carne. </li><li> Mettere le fette di carne nel sacchetto di plastica con l&#39;etichetta &quot;A&quot;. </li><li> Riavvolgere carne &quot;A&quot; e tornare al frigorifero. </li><li> Ripetere i passaggi 2-11 con carni etichettate &quot;B&quot; e &quot;C&quot;. </li></ol> 6. Quantificare fluorescente Polvere Quantificare la polvere fluorescente dopo il completamento del taglio finto (Sezione 5.4) in cucina deli. Per questo procedere come segue: <ol><li> Utilizzare il 5 centimetri x 5 cm template foglio di alluminio sterile e posizionarlo sulle aree segnate in Figura 1. </li><li> Usare un tampone di alginato di calcio di cotone sterile imbevuto di etanolo al 95%, tamponare la zona, e metterli in 6 ml di etanolo al 95% in un tubo di polipropilene sterile. </li><li> Vortex la provetta accuratamente e trasferimento in una cuvetta di vetro per leggere l&#39;assorbanza a 370 nm. </li><li> Fare riferimento alla standard curva per determinare la quantità di polvere fluorescente (y) utilizzando la seguente equazione: y = mx + b dove x è assorbenza, m è la pendenza della curva standard, e b è l&#39;intercetta. </li><li> Per normalizzazione dei dati, calcolare la percentuale di polvere fluorescente per area campionata mediante la seguente formula: </li></ol><img src="/files/ftp_upload/51402/51402eq1.jpg" alt="Formula 1" /> 7. Analisi Video Videotape i partecipanti come essi completare le attività 5,1-5,12. Sincronizzare e salvare le registrazioni video su dischi DVD in modo che tutti gli angoli possono essere visualizzati allo stesso tempo. Guarda il video per registrare il numero di tocchi di mano (il numero di volte in cui i volontari toccano zone della gastronomia finto) su varie superfici per l&#39;ambiente deli (4 ricercatori di differenti analizzeranno i dati completi impostati in modo indipendente).

<ol>
	<li>Sheen, S., Hwang, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mathematical+modeling+the+cross-contamination+of+Escherichia+coli+O157:+H7+on+the+surface+of+ready-to-eat+meat+product+while+slicing.">Mathematical modeling the cross-contamination of Escherichia coli O157: H7 on the surface of ready-to-eat meat product while slicing.</a> Food Microbiol. 27, 37-43 (2010).</li><li>Crandall, P., Neal, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimizing+the+risk+of+Listeria+monocytogenes+in+retail+delis+by+developing+employee+focused,+cost+effective+training.">Minimizing the risk of Listeria monocytogenes in retail delis by developing employee focused, cost effective training.</a> Agric. Food Anal. Bacteriol. 1, 159-174 (2011).</li><li>Koo, O. K., Sirsat, S. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physical+and+chemical+control+of+Salmonella+in+ready-to-eat+products.">Physical and chemical control of Salmonella in ready-to-eat products.</a> Agric. Food Anal. Bacteriol. 2, 56-68 (2012).</li><li>Hanning, I. B., Johnson, M. G., Ricke, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precut+prepackaged+lettuce:+a+risk+for+listeriosis?.">Precut prepackaged lettuce: a risk for listeriosis?.</a> Foodborne Pathog. Dis. 5, 731-746 (2008).</li><li>Hanning, I. B., Nutt, J. D., Ricke, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Salmonellosis+outbreaks+in+the+United+States+due+to+fresh+produce:+sources+and+potential+intervention+measures.">Salmonellosis outbreaks in the United States due to fresh produce: sources and potential intervention measures.</a> Foodborne Pathog. Dis. 6, 635-648 (2008).</li><li>Zhu, M., Du, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+Listeria+monocytogenes+contamination+in+ready&#8208;to&#8208;eat+meat+products.">Control of Listeria monocytogenes contamination in ready&#8208;to&#8208;eat meat products.</a> Compr. Rev. Food Sci. Food Safety. 4, 34-42 (2005).</li><li>Lianou, A., Sofos, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+the+incidence+and+transmission+of+Listeria+monocytogenes+in+ready-to-eat+products+in+retail+and+food+service+environments.">A review of the incidence and transmission of Listeria monocytogenes in ready-to-eat products in retail and food service environments.</a> J. Food Protect. 70, 2172-2198 (2007).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+risk+assessment+of+relative+risk+to+public+health+from+foodborne+Listeria+monocytogenes+among+selected+categories+of+ready-to-eat+foods.">Quantitative risk assessment of relative risk to public health from foodborne Listeria monocytogenes among selected categories of ready-to-eat foods.</a> , .</li><li>Endrikat, S., Gallagher, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparative+risk+assessment+for+Listeria+monocytogenes+in+prepackaged+versus+retail-sliced+deli+meat.">A comparative risk assessment for Listeria monocytogenes in prepackaged versus retail-sliced deli meat.</a> J. Food Protect. 73, 612-619 (2010).</li><li>Pradhan, A. K., Ivanek, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+public+health+impact+of+Listeria+monocytogenes+product-to-product+and+environment-to-product+contamination+of+deli+meats+at+retail.">Comparison of public health impact of Listeria monocytogenes product-to-product and environment-to-product contamination of deli meats at retail.</a> J. Food Protect. 74, 1860-1868 (2011).</li><li>Jones, C. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Handwashing+Technique+Analysis.">Handwashing Technique Analysis.</a> Patent number 5900067. , (1999).</li><li>Gibson, K. E., Koo, O. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Observation+and+relative+quantification+of+cross-contamination+within+a+mock+retail+delicatessen+environment.">Observation and relative quantification of cross-contamination within a mock retail delicatessen environment.</a> Food Control. 31, 116-124 (2013).</li><li>Xiao, M., Zheng, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+and+System+for+Fecal+Detection.">Method and System for Fecal Detection.</a> Patent number 5821546. , (1998).</li><li>Waldroup, A., Kirby, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+and+System+for+Fecal+Detection.">Method and System for Fecal Detection.</a> Patent number 5621215. , (1997).</li><li>Ashby, K. D., Wen, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescence+of+dietary+porphyrins+as+a+basis+for+real-time+detection+of+fecal+contamination+on+meat.">Fluorescence of dietary porphyrins as a basis for real-time detection of fecal contamination on meat.</a> J. Agric. Food Chem. 51, 3502-3507 (2003).</li><li>Cabrera-Diaz, E., Moseley, T. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+protein+marked+Escherichia+coli+biotype+I+strains+as+surrogates+for+enteric+pathogens+in+validation+of+beef+carcass+interventions.">Fluorescent protein marked Escherichia coli biotype I strains as surrogates for enteric pathogens in validation of beef carcass interventions.</a> J. Food Protect. 72, 295-303 (2009).</li><li>Byrd, J., Hargis, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+marker+for+the+detection+of+crop+and+upper+gastrointestinal+leakage+in+poultry+processing+plants.">Fluorescent marker for the detection of crop and upper gastrointestinal leakage in poultry processing plants.</a> Poult. Sci. 81, 70-74 (2002).</li><li>Vorst, K. L., Todd, E. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transfer+of+Listeria+monocytogenes+during+mechanical+slicing+of+turkey+breast+bologna,+and+salami..">Transfer of Listeria monocytogenes during mechanical slicing of turkey breast bologna, and salami..</a> J. Food Protect. 69, 619-626 (2006).</li></ol>

Nessun conflitto di interessi dichiarati.

L&#39;obiettivo generale di questo studio era di dimostrare come la contaminazione incrociata batterica potrebbe verificarsi in un ambiente deli vendita al dettaglio, al fine di sviluppare strategie per controllare e ridurre il rischio di malattie a trasmissione alimentare. L&#39;ambiente deli al dettaglio ha un rischio particolarmente elevato di L. monocytogenes contaminazione. L&#39;USDA-FSIS riferito che salume affettato al negozio al dettaglio ha un sette volte maggiore associazione con listeriosi che la ca...

La contaminazione incrociata dei patogeni nell&#39;ambiente preparazione alimentare, in particolare nella sezione di dettaglio, è una grande preoccupazione per l&#39;aumentato rischio di malattia alimentare da una varietà di fonti, tra le carni e le verdure 1-5. Molto spesso, batteri patogeni entrano ambiente retail attraverso i prodotti alimentari contaminati 6. Alimenti pronti per il consumo preparati a livello di vendita al dettaglio sono di particolare interesse in quanto di solito non c&#39;è ulteriore intervento o trattamento (cottura o riscaldamento) prima del consumo 7. Inoltre, gli agenti patogeni presenti sul cibo contaminato RTE possono poi essere trasferiti ad altri prodotti alimentari o di superfici di contatto con gli alimenti in ambiente retail. Mentre la contaminazione incrociata può avvenire all&#39;interno di praticamente qualsiasi tipo di ambiente alimentare al dettaglio, gastronomie sono di particolare interesse proprio perché l&#39;associazione di RTE salumi con l&#39;agente patogeno Listeria monocytogEnes 2. Sulla base di una valutazione del rischio analisi condotta dalla US Food and Drug Administration (FDA) e il Dipartimento dell&#39;Agricoltura sicurezza alimentare e Inspection Service (USDA-FSIS) degli Stati Uniti, salumi contaminati sono probabilmente responsabili del 90% dei casi di listeriosi - un raro malattia umana ancora grave causata da L. monocytogenes - negli Stati Uniti 8. In generale, salumi affettati presso gli stabilimenti di servizi al dettaglio e il cibo sono stati associati con un rischio più elevato di L. monocytogenes rispetto al presliced ​​salumi in un impianto ispezionato USDA da parte del produttore 9. Questo potrebbe essere a causa della maggiore probabilità di introduzione di agenti patogeni da manipolazione degli alimenti, materie prime in entrata, o alimenti trasformati che possono diventare contaminati di post-trattamento 7. Nel complesso, listeriosi rappresenta circa il 28% dei decessi stimati causati da malattie di origine alimentare ogni anno negli Stati Uniti A causa della arischi aumentati di L. monocytogenes contaminazione salumi affettati al dettaglio, la gastronomia affettatrice stessa è stata identificata come un fattore importante per il trasferimento di superficie di patogeni di origine alimentare in ambiente retail 2,10. Come indicato da Sheen 1, affettare è l&#39;ultima fase di lavorazione prima del consumo, pertanto, l&#39;affettatrice deli deve essere considerato un punto di controllo critico sia per comprendere e prevenire la contaminazione incrociata 1. L&#39;obiettivo generale di questo studio è stato quello di sviluppare una metodologia per monitorare la contaminazione dell&#39;ambiente deli dettaglio utilizzando una polvere fluorescente come Glo Germ. Questo è un composto fluorescente che è stato utilizzato per simulare la contaminazione incrociata batterica e pratiche sanitarie 11,12. Questo studio è stato progettato per monitorare il trasferimento patogeno da carni contaminate al affettatrice, l&#39;ambiente circostante, e altri salumi. E &#39;fondamentale capire le vie di contamminazione per sviluppare sia interventi efficaci e materiale didattico per i dipendenti e manager di vendita al dettaglio. Un approccio simile può essere impiegata per simulare il trasferimento patogeno in altri ambienti di elaborazione (es. pollame e manzo), le aziende agricole e ospedali.

<table border="0" cellpadding="0" cellspacing="0" width="637">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="43">
			<td height="43" style="height:43px;width:216px;">Glo-Germ Powder</td>
			<td style="width:71px;">Glo Germ Co</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Purchased from vendor</td>
			<td style="width:64px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Ethanol</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">E7023</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Permanent markets</td>
			<td style="width:71px;">Sharpie</td>
			<td style="width:119px;"></td>
			<td colspan="2">Purchased from stationary store</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Gloves</td>
			<td style="width:71px;">VWR</td>
			<td style="width:119px;">82026-424</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Deli Meat</td>
			<td style="width:71px;">NA</td>
			<td style="width:119px;">NA</td>
			<td colspan="2">Bologna Chub from regular grocery store</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Cutting Board</td>
			<td style="width:71px;">NA</td>
			<td style="width:119px;">NA</td>
			<td colspan="2">A regukar kitchen cutting board</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Knife</td>
			<td style="width:71px;">NA</td>
			<td style="width:119px;">NA</td>
			<td>A regular kitchen knife&#160;</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">5 x 5 cm sterile templates</td>
			<td style="width:71px;">NA</td>
			<td style="width:119px;">NA</td>
			<td colspan="2">Aluminium foil templates cut into 5x 5 cm templates and sterilized&#160;</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:216px;">15 ml polypropylene centrifuge tubes</td>
			<td style="width:71px;">VWR</td>
			<td style="width:119px;">89039-664</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Cotton swabs</td>
			<td style="width:71px;">Puritan</td>
			<td style="width:119px;">25-806</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Glass cuvettes</td>
			<td style="width:71px;">VWR</td>
			<td style="width:119px;">470019-186</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Vortex</td>
			<td style="width:71px;">VWR</td>
			<td style="width:119px;">58816-121</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:216px;">Flip camera</td>
			<td style="width:71px;">Flip Ultra HD</td>
			<td style="width:119px;">NA</td>
			<td>Purchased online</td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Deli slicer</td>
			<td style="width:71px;">Bizerba</td>
			<td style="width:119px;">SE-12</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:216px;">Deli refrigerator</td>
			<td style="width:71px;">True company</td>
			<td style="width:119px;">TDBD-722</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:216px;">Scale</td>
			<td style="width:71px;"></td>
			<td style="width:119px;">NA</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="85">
			<td height="85" style="height:85px;width:216px;">Spectrophotometer</td>
			<td style="width:71px;">Milton Roy Spectronic 20D</td>
			<td style="width:119px;">NA</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

tracking microbial contamination in retail environments using fluorescent powder - a retail delicatessen environment example

La contaminazione incrociata dei patogeni di origine alimentare in ambiente retail è un problema di salute pubblica contribuendo ad un aumentato rischio di malattie di origine alimentare. Alimenti pronti per il consumo (RTE) trasformati come salumi, formaggi, e in alcuni casi i prodotti freschi, sono stati coinvolti in focolai di malattie di origine alimentare per la contaminazione con agenti patogeni quali Listeria monocytogenes. Per quanto riguarda L. monocytogenes, affettatrici deli sono spesso la principale fonte di contaminazione incrociata. L&#39;obiettivo di questo studio è stato quello di utilizzare un composto fluorescente per simulare la contaminazione batterica e tenere traccia di questa contaminazione in un ambiente di vendita al dettaglio. Una cucina deli finto è stato progettato per simulare l&#39;ambiente di vendita al dettaglio. Salume è stato inoculato con il composto fluorescente e volontari sono stati reclutati per completare una serie di compiti simili a quelle attese di un dipendente di alimentare al dettaglio. I volontari sono stati incaricati di affettare, pacchetto, e conservare la carne in frigorifero deli. Il potenzialecontaminazione incrociata è stata monitorata in ambiente retail finto tamponando aree specifiche e misurando la densità ottica della zona deterso con uno spettrofotometro. I risultati hanno indicato che il frigorifero (cioè deli caso) presa e varie aree sul affettatrice avevano il più alto rischio di contaminazione incrociata. I risultati di questo studio possono essere utilizzati per sviluppare materiale di formazione più mirata per i dipendenti al dettaglio. Inoltre, le metodologie analoghe potrebbero essere utilizzati anche per monitorare la contaminazione microbica in ambienti di produzione alimentare (ad esempio piccole aziende agricole), ospedali, case di cura, navi da crociera e alberghi.

Figura 1 rappresenta le zone del affettatrice che sono stati tamponata dopo i volontari hanno completato i compiti assegnati. I volontari sono stati videoregistrati per analizzare la frequenza media di contatto mano nelle varie superfici. La frequenza di contatto mano è stato analizzato mediante quattro diversi osservatori e media. Questi risultati vengono illustrati nella Figura 2. I dati mostrano che la presa di carne, salumi involucro, salumi, e la carta deli avevano i più alti tas...

Watch this Scientific Journal Video about Tracking Microbial Contamination in Retail Environments Using Fluorescent Powder - A Retail Delicatessen Environment Example at JoVE.com

Tracking Microbial Contamination in Retail Environments Using Fluorescent Powder - A Retail Delicatessen Environment Example

L&#39;obiettivo generale di questo studio era di dimostrare il potenziale meccanismo di contaminazione incrociata di origine alimentare patogeni Listeria monocytogenes in un ambiente deli al dettaglio. Questo metodo può essere applicato ad una varietà di ambienti diversi per monitorare la contaminazione patogeno.

Monitoraggio contaminazione microbica in ambienti di vendita al dettaglio usando fluorescente Powder - Un dettaglio Delicatessen Ambiente Esempio

Cross contamination of foodborne pathogens in the retail environment is a significant public health issue contributing to an increased risk for foodborne ...

tracking-microbial-contamination-retail-environments-using

Research

JoVE Journal

Environment

11.0K Views.  University of Houston.  L'obiettivo generale di questo studio era di dimostrare il potenziale meccanismo di contaminazione incrociata di origine alimentare patogeni Listeria monocytogenes in un ambiente deli al dettaglio. Questo metodo può essere applicato ad una varietà di ambienti diversi per monitorare la contaminazione patogeno. 

Video: Tracking Microbial Contamination in Retail Environments Using Fluorescent Powder - A Retail Delicatessen Environment Example

Determination of Microbial Extracellular Enzyme Activity in Waters, Soils, and Sediments using High Throughput Microplate Assays

Much of the nutrient cycling and carbon processing in natural environments occurs through the activity of extracellular enzymes released by microorganisms. Thus, measurement of the activity of these extracellular enzymes can give insights into the rates of ecosystem level processes, such as organic matter decomposition or nitrogen and phosphorus mineralization. Assays of extracellular enzyme activity in environmental samples typically involve exposing the samples to artificial colorimetric or fluorometric substrates and tracking the rate of substrate hydrolysis. Here we describe microplate based methods for these procedures that allow the analysis of large numbers of samples within a short time frame. Samples are allowed to react with artificial substrates within 96-well microplates or deep well microplate blocks, and enzyme activity is subsequently determined by absorption or fluorescence of the resulting end product using a typical microplate reader or fluorometer. Such high throughput procedures not only facilitate comparisons between spatially separate sites or ecosystems, but also substantially reduce the cost of such assays by reducing overall reagent volumes needed per sample.

Microplate based procedures are described for the colorimetric or fluorometric analysis of extracellular enzyme activity. These procedures allow for the rapid assay of such activity in large numbers of environmental samples within a manageable time frame.

Determinazione del microbica extracellulare Enzyme Activity in Acque, Suoli e sedimenti utilizzando High Throughput micropiastre saggi

Much of the nutrient cycling and carbon  processing in natural environments occurs through the activity of extracellular  enzymes released by ...

Ricerca

Ambiente

Technique for Studying Arthropod and Microbial Communities within Tree Tissues

Phloem tissues of pine are habitats for many thousands of organisms. Arthropods and microbes use phloem and cambium tissues to seek mates, lay eggs, rear young, feed, or hide from natural enemies or harsh environmental conditions outside of the tree. Organisms that persist within the phloem habitat are difficult to observe given their location under bark. We provide a technique to preserve intact phloem and prepare it for experimentation with invertebrates and microorganisms. The apparatus is called a &#8216;phloem sandwich&#8217; and allows for the introduction and observation of arthropods, microbes, and other organisms. This technique has resulted in a better understanding of the feeding behaviors, life-history traits, reproduction, development, and interactions of organisms within tree phloem. The strengths of this technique include the use of inexpensive materials, variability in sandwich size, flexibility to re-open the sandwich or introduce multiple organisms through drilled holes, and the preservation and maintenance of phloem integrity. The phloem sandwich is an excellent educational tool for scientific discovery in both K-12 science courses and university research laboratories.

We provide a technique to preserve intact tree phloem and prepare it for observation. We create an apparatus called a phloem sandwich that allows for the introduction and observation of arthropods, microbes, and other organisms that inhabit phloem tissues.

Tecnica per lo Studio artropodi e comunità microbiche all&#39;interno Albero tessuti

Phloem tissues of pine are habitats for many thousands of organisms.  Arthropods and microbes use phloem and cambium tissues to seek mates, lay eggs, rear ...

An Aquatic Microbial Metaproteomics Workflow: From Cells to Tryptic Peptides Suitable for Tandem Mass Spectrometry-based Analysis

Meta-omic technologies such as metagenomics, metatranscriptomics and metaproteomics can aid in the understanding of microbial community structure and metabolism. Although powerful, metagenomics alone can only elucidate functional potential. On the other hand, metaproteomics enables the description of the expressed in situ metabolism and function of a community. Here we describe a protocol for cell lysis, protein and DNA isolation, as well as peptide digestion and extraction from marine microbial cells collected on a cartridge filter unit (such as the Sterivex filter unit) and preserved in an RNA stabilization solution (like RNAlater). In mass spectrometry-based proteomics studies, the identification of peptides and proteins is performed by comparing peptide tandem mass spectra to a database of translated nucleotide sequences. Including the metagenome of a sample in the search database increases the number of peptides and proteins that can be identified from the mass spectra. Hence, in this protocol DNA is isolated from the same filter, which can be used subsequently for metagenomic analysis.

This protocol is for the extraction and concentration of protein and DNA from microbial biomass collected from seawater, followed by the generation of tryptic peptides suitable for tandem mass spectrometry-based proteomic analysis.

Un flusso di lavoro metaproteomica Aquatic microbica: dalle celle ai Trittico Peptidi per l&#39;analisi basata su spettrometria di massa tandem

Meta-omic technologies such as metagenomics, metatranscriptomics and metaproteomics can aid in the understanding of microbial community structure and ...

Extraction and Analysis of Microbial Phospholipid Fatty Acids in Soils

Phospholipid fatty acids (PLFAs) are key components of microbial cell membranes. The analysis of PLFAs extracted from soils can provide information about the overall structure of terrestrial microbial communities. PLFA profiling has been extensively used in a range of ecosystems as a biological index of overall soil quality, and as a quantitative indicator of soil response to land management and other environmental stressors.
The standard method presented here outlines four key steps: 1. lipid extraction from soil samples with a single-phase chloroform mixture, 2. fractionation using solid phase extraction columns to isolate phospholipids from other extracted lipids, 3. methanolysis of phospholipids to produce fatty acid methyl esters (FAMEs), and 4. FAME analysis by capillary gas chromatography using a flame ionization detector (GC-FID). Two standards are used, including 1,2-dinonadecanoyl-sn-glycero-3-phosphocholine (PC(19:0/19:0)) to assess the overall recovery of the extraction method, and methyl decanoate (MeC10:0) as an internal standard (ISTD) for the GC analysis.

Phospholipid fatty acids provide information about the structure of soil microbial communities. We present methods for extraction from soil samples with a single-phase chloroform mixture, fractionation of extracted lipids using solid phase extraction columns, and methanolysis to produce fatty acid methyl esters, which are analyzed by capillary gas chromatography.

Estrazione e l&#39;analisi delle microbica fosfolipidi acidi grassi nei terreni

Phospholipid fatty acids (PLFAs) are key components of microbial cell membranes. The analysis of PLFAs extracted from soils can provide information about ...

Sampling, Sorting, and Characterizing Microplastics in Aquatic Environments with High Suspended Sediment Loads and Large Floating Debris

The ubiquitous presence of plastic debris in the ocean is widely recognized by the public, scientific communities, and government agencies. However, only recently have microplastics in freshwater systems, such as rivers and lakes, been quantified. Microplastic sampling at the surface usually consists of deploying drift nets behind either a stationary or moving boat, which limits the sampling to environments with low levels of suspended sediments and floating or submerged debris. Previous studies that employed drift nets to collect microplastic debris typically used nets with &#8805;300 &#181;m mesh size, allowing plastic debris (particles and fibers) below this size to pass through the net and elude quantification. The protocol detailed here enables: 1) sample collection in environments with high suspended loads and floating or submerged debris and 2) the capture and quantification of microplastic particles and fibers &lt;300 &#181;m. Water samples were collected using a peristaltic pump in low-density polyethylene (PE) containers to be stored before filtering and analysis in the lab. Filtration was done with a custom-made microplastic filtration device containing detachable union joints that housed nylon mesh sieves and mixed cellulose ester membrane filters. Mesh sieves and membrane filters were examined with a stereomicroscope to quantify and separate microplastic particulates and fibers. These materials were then examined using a micro-attenuated total reflectance Fourier transform infrared spectrometer (micro ATR-FTIR) to determine microplastic polymer type. Recovery was measured by spiking samples using blue PE particulates and green nylon fibers; percent recovery was determined to be 100% for particulates and 92% for fibers. This protocol will guide similar studies on microplastics in high velocity rivers with high concentrations of sediment. With simple modifications to the peristaltic pump and filtration device, users can collect and analyze various sample volumes and particulate sizes.

Most microplastic research to date has occurred in marine systems where suspended solid levels are relatively low. Focus is now shifting to freshwater systems, which may feature high sediment loads and floating debris. This protocol addresses collecting and analyzing microplastic samples from aquatic environments that contain high suspended solid loads.

Campionamento, ordinamento e caratterizzando microplastiche negli ambienti acquatici con carichi di materiale solido in sospensione alta e grandi detriti galleggianti

The ubiquitous presence of plastic debris in the ocean is widely recognized by the public, scientific communities, and government agencies. However, only ...

Detection of 3-Nitrotyrosine in Atmospheric Environments via a High-performance Liquid Chromatography-electrochemical Detector System

3-nitrotyrosine (3-NT) is generated from the tyrosine residue in atmospheric bio-aerosol proteins via a reaction with ozone (O3) and nitrogen dioxide (NO2). Stable 3-NT is a specific marker for oxidative damage and is reported to have a promotive effect to elicit allergies. In the present study, we report the development of a highly sensitive assay to quantify 3-NT in air sampler filters to collect &#60; 2.5 &#181;m of particulate matter (PM2.5) from urban environmental air, including bio-aerosol. In this method, a 6 mm-diameter round hole was cut from the filters of air samplers and mixed with a nonspecific protease cocktail in order to hydrolyze proteins. Protein samples digested to the amino acid level were tested for 3-NT using a high-performance liquid chromatography-electrochemical detector (HPLC-ECD). The maximum 3-NT content was detected in a prefilter for PM of sizes from 4.5 to 7.3 &#956;m, with a detection limit of 1.13 pg/m3.

Detection of 3-Nitrotyrosine in Atmospheric Environments via a High-performance Liquid Chromatography-electrochemical Detector System

We present a method to detect 3-nitrotyrosine chemical modifications of atmospheric proteins with 6 mm-diameter rounds cut from air sampler prefilters using a high-performance liquid chromatography-electrochemical detector (HPLC-ECD).

Rilevamento di 3-nitrotirosina in ambienti atmosferici tramite un alto rendimento liquido rivelatore elettrochimico cromatografia sistema

3-nitrotyrosine (3-NT) is generated from the tyrosine residue in atmospheric bio-aerosol proteins via a reaction with ozone (O3) and nitrogen dioxide ...

Fluorescently Labeled Bacteria as a Tracer to Reveal Novel Pathways of Organic Carbon Flow in Aquatic Ecosystems

Elucidating trophic interactions, such as predation and its effects, is a frequent task for many researchers in ecology. The study of microbial communities has many limitations, and determining a predator, prey, and predatory rates is often difficult. Presented here is an optimized method based on the addition of fluorescently labelled prey as a tracer, which allows for reliable quantitation of the grazing rates in aquatic predatory eukaryotes and estimation of nutrient transfer to higher trophic levels.

Presented here is a protocol for a single-cell, epifluorescence microscopy-based technique to quantify grazing rates in aquatic predatory eukaryotes with high precision and taxonomic resolution.

Fluorescently etichettato batteri come un tracciante per rivelare nuovi percorsi di flusso organico di carbonio negli ecosistemi acquatici

Elucidating trophic interactions, such as predation and its effects, is a frequent task for many researchers in ecology. The study of microbial ...

Enrichment and Detection of Clostridium perfringens Toxinotypes in Retail Food Samples

Clostridium perfringens (C. perfringens) is a prolific toxin producer and causes a wide range of diseases in various hosts. C. perfringens is categorized into five different toxinotypes, A through E, based on the carriage of four major toxin genes. The prevalence and distribution of these various toxinotypes is understudied, especially their pervasiveness in American retail food. Of particular interest to us are the type B and D strains, which produce epsilon toxin, an extremely lethal toxin suggested to be the environmental trigger of multiple sclerosis in humans. To evaluate the presence of different C. perfringens toxinotypes in various food samples, we developed an easy method to selectively culture these bacteria without the use of an anaerobic container system only involving three culturing steps. Food is purchased from local grocery stores and transported to the laboratory under ambient conditions. Samples are minced and inoculated into modified rapid perfringens media (RPM) and incubated overnight at 37 &#176;C in a sealed, airtight conical tube. Overnight cultures are inoculated onto a bottom layer of solid Tryptose Sulfite Cycloserine (TSC) agar, and then overlaid with a top layer of molten TSC agar, creating a &#34;sandwiched&#34;, anaerobic environment. Agar plates are incubated overnight at 37 &#176;C and then evaluated for appearance of black, sulfite-reducing colonies. C. perfringens-suspected colonies are removed from the TSC agar using sterile eye droppers, and inoculated into RPM and sub-cultured overnight at 37 &#176;C in an airtight conical tube. DNA is extracted from the RPM subculture, and then analyzed for the presence of C. perfringens toxin genes via polymerase chain reaction (PCR). Depending on the type of food sampled, typically 15&#8211;20% of samples test positive for C. perfringens.

Enrichment and Detection of Clostridium perfringens Toxinotypes in Retail Food Samples

The objective of this protocol is to detect different Clostridium perfringens toxinotypes in locally purchased foods, particularly epsilon toxin producing strain types B and D, without the use of anaerobic chambers.

Arricchimento e rilevamento di Clostridium perfezioni tossinotipi nei campioni di alimenti al dettaglio

Clostridium perfringens (C. perfringens) is a prolific toxin producer and causes a wide range of diseases in various hosts. C. perfringens is categorized ...

In Situ Chemotaxis Assay to Examine Microbial Behavior in Aquatic Ecosystems

Microbial behaviors, such as motility and chemotaxis (the ability of a cell to alter its movement in response to a chemical gradient), are widespread across the bacterial and archaeal domains. Chemotaxis can result in substantial resource acquisition advantages in heterogeneous environments. It also plays a crucial role in symbiotic interactions, disease, and global processes, such as biogeochemical cycling. However, current techniques restrict chemotaxis research to the laboratory and are not easily applicable in the field. Presented here is a step-by-step protocol for the deployment of the in situ chemotaxis assay (ISCA), a device that enables robust interrogation of microbial chemotaxis directly in the natural environment. The ISCA is a microfluidic device consisting of a 20 well array, in which chemicals of interest can be loaded. Once deployed in aqueous environments, chemicals diffuse out of the wells, creating concentration gradients that microbes sense and respond to by swimming into the wells via chemotaxis. The well contents can then be sampled and used to (1) quantify strength of the chemotactic responses to specific compounds through flow cytometry, (2) isolate and culture responsive microorganisms, and (3) characterize the identity and genomic potential of the responding populations through molecular techniques. The ISCA is a flexible platform that can be deployed in any system with an aqueous phase, including marine, freshwater, and soil environments.

Presented here is the protocol for an in situ chemotaxis assay, a recently developed microfluidic device that enables studies of microbial behavior directly in the environment.

In Situ Chemotaxis Assay per esaminare il comportamento microbico negli ecosistemi acquatici

Microbial behaviors, such as motility and chemotaxis (the ability of a cell to alter its movement in response to a chemical gradient), are widespread ...

Evaluating the Impact of Hydraulic Fracturing on Streams using Microbial Molecular Signatures

Hydraulic fracturing (HF), commonly called &#34;fracking&#34;, uses a mixture of high-pressure water, sand, and chemicals to fracture rocks, releasing oil and gas. This process revolutionized the U.S. energy industry, as it gives access to resources that were previously unobtainable and now produces two-thirds of the total natural gas in the United States. Although fracking has had a positive impact on the U.S. economy, several studies have highlighted its detrimental environmental effects. Of particular concern is the effect of fracking on headwater streams, which are especially important due to their disproportionately large impact on the health of the entire watershed. The bacteria within those streams can be used as indicators of stream health, as the bacteria present and their abundance in a disturbed stream would be expected to differ from those in an otherwise comparable but undisturbed stream. Therefore, this protocol aims to use the bacterial community to determine if streams have been impacted by fracking. To this end, sediment, and water samples, from streams near fracking (potentially impacted) and upstream or in a different watershed of fracking activity (unimpacted) must be collected. Those samples are then subjected to nucleic acid extraction, library preparation, and sequencing to investigate microbial community composition. Correlational analysis and machine learning models can subsequently be employed to identify which features are explanative of variation in the community, as well as identification of predictive biomarkers for fracking&#39;s impact. These methods can reveal a variety of differences in the microbial communities among headwater streams, based on the proximity to fracking, and serve as a foundation for future investigations on the environmental impact of fracking activities.

Here, we present a protocol to investigate the impacts of hydraulic fracturing on nearby streams by analyzing their water and sediment microbial communities.

Valutazione dell'impatto della fratturazione idraulica sui flussi utilizzando le firme molecolari microbiche

Hydraulic fracturing (HF), commonly called &#34;fracking&#34;, uses a mixture of high-pressure water, sand, and chemicals to fracture rocks, releasing oil ...