9 research outputs found
NMR and computational data of two novel antimicrobial peptides
No full textAbstractHere we report details on the design and conformational analysis of two novel peptides showing antimicrobial properties, as reported in the research article, “New antimicrobial peptides against foodborne pathogens: from in silico design to experimental evidence” G. Palmieri, M. Balestrieri, Y.T.R. Proroga, L. Falcigno, A. Facchiano, A. Riccio, F. Capuano, R. Marrone, G. Campanile, A. Anastasio (2016) [1]. NMR data, such as chemical shifts in two different solvents as well as aCH protons deviations from random coil values and NOE patterns, are shown together with the statistics of structural calculations. Strategy and particulars of molecular design are presented
Bactericidal and antibiofilm activity of bactenecin-derivative peptides against the food-pathogen Listeria monocytogenes : New perspectives for food processing industry
No full text: Antimicrobial peptides have received great attention for their potential benefits to extend the shelf-life of food-products. Innate defense regulator peptide-1018 (IDR-1018) represents a promising candidate for such applications, due to its broad-spectrum antimicrobial activity, although food-isolated pathogens have been poorly investigated. Herein, we describe the design and the structural-functional characterization of a new 1018-derivative peptide named 1018-K6, in which the alanine in position 6 was replaced with a lysine. Spectroscopic analysis revealed a noticeable switch from β-sheet to helical conformations of 1018-K6 respect to IDR-1018, with a faster folding kinetic and increased structural stability. Moreover, 1018-K6 evidenced a significant antibiofilm/bactericidal efficiency specifically against Listeria monocytogenes isolates from food-products and food-processing environments, belonging to serotype 4b involved in the majority of human-listeriosis cases, with EC50 values two- five-fold lower than those measured for IDR-1018. Therefore, a single amino-acid substitution in IDR-1018 sequence produced severe changes in peptide conformation and antimicrobial performances
Characterization of non-typhoidal Salmonella enterica strains of human origin in central and southern Italy
No full textNon-typhoidal Salmonella enterica infection is a significant public health problem worldwide. The aim of this study was to characterize Salmonella enterica strains isolated from human specimens in central and southern Italy, for epidemiological studies. One hundred and fifty S. enterica strains were serotyped. Isolates were tested for their antimicrobial susceptibility, by disk diffusion method. The molecular characterizations, based on PCR, were carried out for the detection of invA gene and other virulence elements and phage marker genes. Eighteen different Salmonella serotypes were identified. The most common serotypes detected were S. Typhimurium, S. Enteritidis, the monophasic variant of S. Typhimurium (S. 4,[5],12:i:-), and S. Napoli. High resistance rates were recorded for tetracycline (64%), streptomycin (62%), sulphonamide (57%), and ampicillin (56%). The ASSuT R-type, also associated to resistance to other antibiotics, was highly prevalent in S. 4,[5],12:i:- (97%) and S. Typhimurium (55%), while the ACSSuT Rtype, also associated to other antibiotics, was observed prevalently in S. Typhimurium (20.4%). The genes of more common detection were invA (100%), sspH2 (86.6%), gtgB (84.6%), g8 (80%), sodC1 (77.3%), gipA (52.6%), sspH1 (52.6%)
P08 | Attività di monitoraggio ambientale e identificazione di shewanella spp. presso uno stabilimento di trasformazione prodotti ittici: risultati preliminari
No full textScopo. Il genere Shewanella spp. comprende batteri Gram-negativi noti per la capacità di ridurre composti di metalli pesanti e nitrati, qualità che li rende rilevanti sia in ambito ecologico che biotecnologico. Questo batterio emergente è stato isolato da diverse matrici ambientali, tra cui acque dolci e marine, sedimenti e superfici contaminate, evidenziando un’elevata adattabilità e una notevole resistenza in condizioni ambientali variabili. Nel settore alimentare, Shewanella spp. è stata riscontrata in prodotti ittici (pesci, molluschi bivalvi, crostacei), carni fresche e, più raramente, in ortaggi irrigati, suggerendo come principali vie di contaminazione l’ambiente e pratiche igieniche inadeguate. In questo contesto, il presente studio ha avuto come obiettivo l’isolamento di Shewanella spp. da superfici ambientali e attrezzature a contatto con alimenti all’interno di uno stabilimento di trasformazione di prodotti ittici, con lo scopo di effettuare un monitoraggio microbiologico finalizzato a valutare l’entità della biocontaminazione e verificare l’efficacia delle procedure di sanificazione aziendali. Metodi. L’indagine è stata condotta nel biennio 2024-2025 in uno stabilimento situato in Campania, mediante campionamento microbiologico effettuato in tre aree operative: superfici ambientali, utensili e attrezzature. Il campionamento è stato eseguito secondo la norma ISO 18593:2018, utilizzando sponge bag sterili in cellulosa (Whirl-Pak, WI, USA) pre-idratate con Buffered Peptone Water (BPW; Thermo Fisher Scientific, UK). Dalle sponge sono state effettuate due diluizioni seriali e seminate per spatolamento su Baird-Parker agar (Thermo Fisher Scientific, UK). Le piastre sono state, successivamente, incubate a 37°C per 24 ore. Le colonie sospette, selezionate sulla base delle caratteristiche morfologiche, sono state, infine, identificate mediante spettrometria di massa MALDI-TOF (Bruker, Germany). Nel corso del monitoraggio ambientale svolto tra il 2024 e il 2025 sono stati effettuati complessivamente 74 campionamenti mediante sponge bag, distribuiti in tre aree operative: 27 sponge sulle superfici ambientali, 20 sugli utensili e 27 sulle attrezzature. Risultati. Dall’analisi microbiologica il genere Shewanella è stato isolato in 31 campioni su 74, con una positività complessiva pari al 41,9%. In particolare, si è osservato un netto incremento del numero di campioni positivi tra i due anni di monitoraggio, evidenziando una crescita significativa della frequenza di isolamento del batterio nel secondo anno di indagine. La distribuzione dei campioni risultati positivi nelle diverse aree operative ha mostrato alcune differenze rilevanti: nelle superfici ambientali sono stati rilevati 7 campioni positivi su 27 (25,9%); negli utensili, 13 campioni positivi su 20 (65%); infine, nell’area delle attrezzature 11 campioni positivi su 27 (40,7%). Conclusioni. L’indagine microbiologica condotta ha evidenziato come utensili e attrezzature costituiscano un importante serbatoio di contaminazione da Shewanella spp. mostrando una percentuale di positività quasi doppia rispetto a quella rilevata sulle superfici ambientali. Questo risultato indica che i materiali e le superfici direttamente a contatto con il prodotto ittico rappresentano un punto critico per la diffusione del microrganismo. Tali evidenze sottolineano la necessità di rafforzare e ottimizzare le procedure di sanificazione, introducendo strategie mirate e più rigorose, per ridurre in modo significativo il rischio di contaminazione crociata e tutelare la sicurezza microbiologica del prodotto finito
P08 | Environmental monitoring and identification of Shewanella spp. at a seafood processing plant: preliminary results
No full textPurpose. The genus Shewanella spp. includes Gram-negative bacteria known for their ability to reduce heavy metal compounds and nitrates, a quality that makes them relevant in both ecological and biotechnological fields. This emerging bacterium has been isolated from various environmental matrices, including freshwater and marine waters, sediments, and contaminated surfaces, highlighting its high adaptability and remarkable resistance under varying environmental conditions. In the food sector, Shewanella spp. has been found in seafood products (fish, bivalve mollusks, crustaceans), fresh meats, and, less commonly, in irrigated vegetables, suggesting that the main routes of contamination are the environment and inadequate hygiene practices. In this context, the objective of the present study was to isolate Shewanella spp. from environmental surfaces and food contact equipment within a seafood processing plant, with the aim of conducting microbiological monitoring to assess the extent of biocontamination and verify the effectiveness of the company's sanitation procedures. Methods. The investigation was conducted in the two-year period 2024-2025 at a facility located in Campania, through microbiological sampling performed in three operational areas: environmental surfaces, utensils, and equipment. Sampling was performed according to ISO 18593:2018, using sterile cellulose sponge bags (Whirl-Pak, WI, USA) pre-hydrated with Buffered Peptone Water (BPW; Thermo Fisher Scientific, UK). Two serial dilutions were made from the sponges and spread-plated onto Baird-Parker agar (Thermo Fisher Scientific, UK). The plates were subsequently incubated at 37°C for 24 hours. Suspicious colonies, selected based on morphological characteristics, were finally identified using MALDI-TOF mass spectrometry (Bruker, Germany). During the environmental monitoring conducted between 2024 and 2025, a total of 74 samples were collected using sponge bags, distributed across three operational areas: 27 on environmental surfaces, 20 on utensils, and 27 on equipment. Results. From the microbiological analysis, the genus Shewanella was isolated in 31 out of 74 samples, with an overall positivity rate of 41.9%. Specifically, a clear increase in the number of positive samples was observed between the two years of monitoring, highlighting a significant growth in the frequency of bacterial isolation in the second year of the investigation. The distribution of positive samples across the different operational areas showed some significant differences: 7 out of 27 environmental surface samples tested positive (25.9%); in the tools, 13 out of 20 samples were positive (65%); Finally, in the equipment area, 11 out of 27 samples were positive (40.7%). Conclusions. The microbiological investigation conducted highlighted that utensils and equipment are a significant reservoir of contamination by Shewanella spp., showing a positivity rate almost double that found on environmental surfaces. This result indicates that materials and surfaces in direct contact with the fish product represent a critical point for the spread of the microorganism. These findings highlight the need to strengthen and optimize sanitation procedures by introducing targeted and more rigorous strategies to significantly reduce the risk of cross-contamination and ensure the microbiological safety of the finished product
Functionalized Polymeric Materials with Bio-Derived Antimicrobial Peptides for "Active" Packaging
No full textFood packaging is not only a simple protective barrier, but a real “active” component, which is expected to preserve food quality, safety and shelf-life. Therefore, the materials used for packaging production should show peculiar features and properties. Specifically, antimicrobial packaging has recently gained great attention with respect to both social and economic impacts. In this paper, the results obtained by using a polymer material functionalized by a small synthetic peptide as “active” packaging are reported. The surface of Polyethylene Terephthalate (PET), one of the most commonly used plastic materials in food packaging, was plasma-activated and covalently bio-conjugated to a bactenecin-derivative peptide named 1018K6, previously characterized in terms of antimicrobial and antibiofilm activities. The immobilization of the peptide occurred at a high yield and no release was observed under different environmental conditions. Moreover, preliminary data clearly demonstrated that the “active” packaging was able to significantly reduce the total bacterial count together with yeast and mold spoilage in food-dairy products. Finally, the functionalized-PET polymer showed stronger efficiency in inhibiting biofilm growth, using a Listeria monocytogenes strain isolated from food products. The use of these “active” materials would greatly decrease the risk of pathogen development and increase the shelf-life in the food industry, showing a real potential against a panel of microorganisms upon exposure to fresh and stored products, high chemical stability and re-use possibility
Detection of pathogenic <i>Vibrio</i> spp. in foods: polymerase chain reaction-based screening strategy to rapidly detect pathogenic <i>Vibrio parahaemolyticus</i>, <i>Vibrio cholerae</i>, and <i>Vibrio vulnificus</i> in bivalve mollusks and preliminary results
No full textThe majority of human diseases attributed to seafood are caused by Vibrio spp. and the most commonly reported species are Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae. The conventional methods for the detection of Vibrio species involve the use of selective media, which are inexpensive and simple but time-consuming. The present work aimed to develop a rapid method based on the use of multiplex real-time polymerase chain reaction (PCR) to detect V. parahaemolyticus, V. vulnificus, and V. cholerae in bivalve mollusks. 30 aliquots of bivalve mollusks (Mytilus galloprovincialis) were experimentally inoculated with two levels of V. parahaemolyticus, V. vulnificus, and V. cholerae. ISO 21872-1:2017 was used in parallel for qualitative analysis. The limit of detection of 50% was 7.67 CFU/g for V. cholerae, 0.024 CFU/g for V. vulnificus, and 1.36 CFU/g for V. parahaemolyticus. For V. vulnificus and V. cholerae, the real-time PCR protocol was demonstrated to amplify the pathogens in samples seeded with the lowest and highest levels. The molecular method evaluated showed a concordance rate of 100% with the reference microbiological method. V. parahaemolyticus was never detected in samples contaminated with the lowest level, and it was detected in 14 samples (93.33%) seeded with the highest concentration. In conclusion, the multiplex real-time PCR developed proved to be reliable for V. vulnificus and V. cholerae. Results for V. parahaemolyticus are promising, but further analysis is needed. The proposed method could represent a quick monitoring tool and, if used, would allow the implementation of food safety
Fresh produce and microbial contamination: persistence during the shelf life and efficacy of domestic washing methods
No full textThe transmission of enteric pathogens by fresh produce depends on the survival of the bacteria organisms during the product shelf-life. The removal of any potentially hazardous microorganism from the vegetables is therefore dependent on the washing and sanitizing techniques employed by individual households. For this purpose, in this work we investigated the persistence of enteric bacteria, using as model Salmonella enterica serovar Napoli (S. Napoli) and Yersinia enterocolitica, in vegetables stored at refrigeration temperature (4 °C). The efficiency of tap water and different chlorine solutions for cleaning vegetables experimentally contaminated with Y. enterocolitica were tested. The results showed that in lettuce spiked with different concentrations of S. Napoli and Y. enterocolitica, both microorganisms were still detected after seven days of storage at 4 °C. Lettuce contaminated with low concentrations of Y. enterocolitica was not decontaminated by washing with tap water or with water added with 60 ppm of chlorine. The presence of Y. enterocolitica in lettuce was reduced of about 1-2 logs after washing with water added with 220 ppm of chlorine. The addition of low concentration of chlorine in post arvest washing processes represents a useful tool to reduce the contamination of the vegetables, with consequent reduction of the risks. However, since complete decontamination was not achieved, foodborne infections linked to fresh produce can still be possible, although contamination is avoided during primary production.
European validation of Real-Time PCR method for detection of Salmonella spp. in pork meat
No full textThe classical microbiological method for detection of Salmonella spp. requires more than five days for final confirmation, and consequently there is a need for an alternative methodology for detection of this pathogen particularly in those food categories with a short shelf-life. This study presents an international (at European level) ISO 16140-based validation study of a non-proprietary Real-Time PCR-based method that can generate final results the day following sample analysis. It is based on an ISO compatible enrichment coupled to an easy and inexpensive DNA extraction and a consolidated Real-Time PCR assay. Thirteen laboratories from seven European Countries participated to this trial, and pork meat was selected as food model. The limit of detection observed was down to 10CFU per 25g of sample, showing excellent concordance and accordance values between samples and laboratories (100%). In addition, excellent values were obtained for relative accuracy, specificity and sensitivity (100%) when the results obtained for the Real-Time PCR-based methods were compared to those of the ISO 6579:2002 standard method. The results of this international trial demonstrate that the evaluated Real-Time PCR-based method represents an excellent alternative to the ISO standard. In fact, it shows an equal and solid performance as well as it reduces dramatically the extent of the analytical process, and can be easily implemented routinely by the Competent Authorities and Food Industry laboratories
