Hygienic quality of dehydrated aromatic herbs marketed in Southern Portugal

Dehydrated aromatic herbs are highly valued ingredients, widely used at home level and by food processing industry, frequently added to a great number of recipes in the Mediterranean countries. Despite being considered low-moisture products and classified as GRAS, during pre and post-harvesting stages of production they are susceptible of microbial contamination. In Europe an increasing number of food recalls and disease outbreaks associated with dehydrated herbs have been reported in recent years. In this study the microbial quality of 99 samples of aromatic herbs (bay leaves, basil, coriander, oregano, parsley, Provence herbs, rosemary and thyme) collected from retails shops in the region of Algarve (Southern Portugal) was assessed. All the samples were tested by conventional methods and were assayed for the total count of aerobic mesophilic microorganisms, Salmonella spp., Escherichia coli, coagulase-positive staphylococci and filamentous fungi. Almost 50 % of the herbs did not exceed the aerobic mesophilic level of 104 CFU/g. The fungi count regarded as unacceptable (106 CFU/g) was not found in any of the tested herbs, while 84 % of the samples ranged from ≤102 to 104 CFU/g. No sample was positive for the presence of Salmonella spp., Escherichia coli and staphylococci. The results are in compliance with the European Commission criteria although they point out to the permanent need of surveillance on the good standards of handling/cooking practices as well as the importance of avoiding contamination at production, retailing and distribution. The microbiological hazards associated with the pathogenic and toxigenic microbiota of dried herbs remain as a relevant public health issue, due to the fact that they are added to foods not submitted to any following lethal procedure. Control measures should be adopted in order to ensure that all phases of their supply chain respect the food safety standards.FCT: UID/BIA/04325/2019.info:eu-repo/semantics/publishedVersio

Microbiological Quality of Nuts, Dried and Candied Fruits, Including the Prevalence of Cronobacter spp.

Cronobacter genus bacteria are food-borne pathogens. Foods contaminated with Cronobacter spp. may pose a risk to infants or immunocompromised adults. The aim of this study was to determine the microbiological quality of nuts, seeds and dried fruits with special emphasis on the occurrence of Cronobacter spp. Analyses were carried out on 64 samples of commercial nuts (20 samples), dried fruits (24), candied fruits (8), seeds (4), and mixes of seeds, dried fruits and nuts (8). The samples were tested for the total plate count of bacteria (TPC), counts of yeasts and molds, and the occurrence of Cronobacter spp. Cronobacter isolates were identified and differentiated by PCR-RFLP (Polymerase Chain Reaction - Restriction Fragments Length Polymorphism) and RAPD-PCR (Random Amplified Polymorphic DNA by PCR) analysis. TPC, and yeasts and molds were not detected in 0.1 g of 23.4%, 89.1%, and 32.8% of the analyzed samples. In the remaining samples, TPC were in the range of 1.2–5.3 log CFU g−1. The presence/absence of Cronobacter species was detected in 12 (18.8%) samples of: nuts (10 samples), and mixes (2 samples). The 12 strains of Cronobacter spp. included: C. sakazakii (3 strains), C. malonaticus (5), and C. turicensis (4). The results of this study contribute to the determination of the presence and species identification of Cronobacter spp. in products of plant origin intended for direct consumption

ASSESSMENT OF PROBIOTIC PROPERTIES AND SAFETY OF LACTIC ACID BACTERIA ISOLATED FROM SOUTH SULAWESI ETHNIC CHEESE

Probiotic bacteria have been used widely as a functional food and health supplements. The functionality and safety of probiotics are the prerequisites given by WHO (World Health Organization) and FAO (Food Agricultural Organization) before utilizing probiotics. This study focuses on assessing probiotic properties and the safety of the lactic acid bacteria (LAB) isolated from dangke—traditional cheese of South Sulawesi. In the current study, the assessment of probiotic properties was carried by assessing its tolerance against low pH and bile salts. Safety assessments were divided into two assays viz., susceptibility testing and hemolytic activity. LAB from dangke demonstrated tolerance against low pH, bile salt and susceptibility against four types of antibiotics (ampicillin, cefotaxime, erythromycin, and tetracycline). Unfortunately, resistance towards gentamycin and an a-hemolytic activity was observed. This bacterium met the functional criteria from probiotics but failed to meet the safety criteria for probiotic safety

YEAST PROBIOTICS WITH POTENTIAL TO ASSIMILATE CHOLESTEROL IN VITRO

 In the last two decades the use of yeasts as new probiotics has increased significantly. Therefore, our current research was focused on the investigation of yeasts for novel probiotic development in Bali. The main objectives of this research were to isolate and characterize yeasts isolated from ragi tape (dried mix cultures of microorganisms normally used in the fermentation of rice or cassava in Indonesia) and tape ketan (fermented sticky rice) for possible use as yeast-based novel probiotics, with capability to assimilate cholesterol in vitro. In this study, the potential yeast isolates were evaluated for survival at low pH conditions (pH 2, 3, or 4) and in high levels of sodium deoxicholic (NaDC), at concentrations of 0.2, 0.4, or 0.6 mM. In addition, the yeast isolates were also evaluated for their ability to assimilate cholesterol in vitro and to elucidate biotransformation of cholic acid into deoxycholic acid. This study led to 10 isolates that were resistant to pH levels of 2, 3, or 4 and to NaDC at concentration of higher than 0.4 mM. Most of those isolates were also found to assimilate cholesterol in vitro at the rate of between 18% and 76% in 24 hours incubation. In the biotransformation test, none of those isolates transformed cholic acid into deoxycholic acid, indicating that they are safe and have potential to be developed into novel probiotics, either for human or cattl

Molecular detection of fungi in paprika, chili powder and black pepper

Paprika powder, chili powder, and black pepper are among the most frequently used spices in the world. The Internal Transcribed Spacer (ITS) regions were identified by high sequence similarity with the ITS regions of many microscopic fungi, especially representatives of the phylum Ascomycota, from 18 different spice samples that were examined. However, supplied quality certificates indicated that 10 of the 18 samples had no contamination present and were safe for human consumption. The various genera of fungi that were identified from the spices are considered to be a food safety concern as they are able to produce mycotoxins. Qualitative detection was supplemented by positive detection of viable fungal DNA using qPCR for the genera Aspergillus/Penicillium in two paprika powder and black pepper samples. These results concurred with the control analysis using axenic cultures. The described methods can be used for routine testing of spices to provide safe spices and other products to consumers.O

Assessing effectiveness of Komagataeibacter strains for producing surface-microstructured cellulose via guided assembly-based biolithography.

In this study, a medical device made of surface microstructured bacterial cellulose was produced using cellulose‑producing acetic acid bacteria wild‑type strains in combination with guided assembly‑based biolithography. The medical device aims at interfering with the cell’s focal adhesion establishment and maturation around implantable devices placed in soft tissues by the symmetrical array on its surface. A total of 25 Komagataeibacter strains was evaluated over a three‑step selection. In the first step, the ability of strains to produce a suitable bacterial cellulose layer with high production yield was examined, then nine strains, with a uniform and smooth layer of bacterial cellulose, were cultured in a custom‑made silicone bioreactor and finally the characteristics of the symmetrical array of topographic features on the surface were analysed. Selected strains showed high inter and intra species variability in bacterial cellulose production. The devices obtained by K2G30, K1G4, DSM 46590 (Komagataeibacter xylinus), K2A8 (Komagataeibacter sp.) and DSM 15973T (Komagataeibacter sucrofermentas) strains were pouched‑formed with hexagonal surface pattern required for reducing the formation of fibrotic tissue around devices, once they are implanted in soft tissues. Our findings revealed the effectiveness of the selected Komagataeibacter wild‑type strains in producing surface microstructured bacterial cellulose pouches for making biomedical devices

Innovative Nonthermal Technologies: Chlorophyllin and Visible Light Significantly Reduce Microbial Load on Basil

Bosiljak je jedna od najpopularnijih začinskih biljaka zbog velikog udjela biološki aktivnih spojeva. Međutim, u svijetu je zabilježeno nekoliko epidemija uzrokovanih konzumacijom bosiljka kontaminiranog raznim patogenim bakterijama. Svrha je ovoga rada bila primijeniti netermički i ekološki prihvatljiv postupak fotosenzibilizacije za mikrobiološku kontrolu bosiljka, prirodno kontaminiranog mezofilnim bakterijama te inokuliranog termorezistentom patogenom bakterijom Listeria monocytogenes 56Ly. Dobiveni rezultati pokazuju da je nakon uranjanja bosiljka u otopinu klorofilina koncentracije od 1,5·10^(-4) M tijekom 15 min i izlaganja vidljivoj svjetlosti valne duljine od 405 nm tijekom 15 min bitno smanjen broj ukuphih aerobnih mikrooganizama, i to za 1,3 log CFU/g, te termorezistentne L. monocytogenes 56Ly, i to sa 6,1 log CFU/g u kontrolnom uzorku na 4,5 log CFU/g u tretiranim uzorcima. Bitno je naglasiti da ovaj postupak nije utjecao na aktivnosti polifenol oksidaze i pektin esteraze. Dobiveni rezultati potkrijepljuju ideju da bi se u budućnosti fotosenzibilizacija, zbog svoje velike selektivnosti, antimikrobnog učinka i netermičkog djelovanja, mogla upotrijebiti za razvoj sigurnog, netermičkog i ekološki prihvatljivog postupka konzerviranja različitih vrsta voća i povrća.Due to the high amount of biologically active compounds, basil is one of the most popular herbs. However, several outbreaks have been reported in the world due to the consumption of basil contaminated with different food pathogens. The aim of this study is to apply nonthermal and ecologically friendly approach based on photosensitization for microbial control of basil which was naturally contaminated with mesophils and inoculated with thermoresistant food pathogen Listeria monocytogenes 56Ly. The obtained data indicate that soaking the basil in 1.5·10^(-4) M chlorophyllin (Chl) for 15 min and illumination with light for 15 min at 405 nm significantly reduced total aerobic microorganisms on basil by 1.3 log CFU/g, and thermoresistant L. monocytogenes 56Ly from 6.1 log CFU/g in control to 4.5 log CFU/g in the treated samples. It is important to note that this treatment had no impact on enzymatic activity of polyphenol oxidase and pectinesterase. Results obtained in this study support the idea that photosensitization technique with its high selectivity, antimicrobial efficiency and nonthermal nature can serve in the future for the development of safe nonthermal and environmentally friendly preservation technology for different fruits and vegetables

Bacteriological hazards and their control in spices

Mausteet ovat monipuolinen ryhmä raaka-aineita, joita käytetään niiden moninaisten käyttötarkoitusten puolesta laajasti elintarviketuotannossa ja -teollisuudessa. Mausteina käytetään erilaisten kasvien osia, esimerkkinä pippuri on marja ja kanelia saadaan puolestaan puun kaarnasta. Suomessa tehdyn maustetutkimuksen perusteella suosituimmiksi mausteiksi nousivat mustapippuri, paprikajauhe, chilimauste ja curry. Yrteistä käytetyimpiä ovat basilika ja oregano. Mausteet kuivatetaan, jotta niiden säilyvyys parantuu, minkä takia ne säilyvätkin mikrobiologisen laatunsa puolesta pitkään. Mausteisiin liittyvät bakteriologiset riskit johtuvatkin ruokamyrkytysbakteerikontaminaatiosta, joka voi tapahtua niin alkutuotannossa kuin myöhemmin varastoinnin, prosessoinnin, tai jakelun tai sen jälkeisissä vaiheissa. Vaikka mausteet yleisesti mielletään turvallisiksi, tiedetään että mausteissa esiintyvät patogeeniset bakteerit voivat aiheuttaa ruokamyrkytysepidemioita. Kirjallisuuskatsauksen perusteella merkittävimmäksi bakteeriksi nousi salmonella. Salmonellan prevalenssi on vaihdellut eri tutkimuksissa aina 0,5 % jopa 18,2 %. Viime vuonna Eurooppaan tuotujen mausteiden valvontanäytteen oton perusteella salmonellan prevalenssiksi saatiin 0,83 %. Mustapippurin havaittiin olevan bakteriologisesti korkeimmassa riskissä, sillä jopa 80 % vuonna 2021 tehdyistä RASFF-hälytyksistä liittyivät mustapippureihin. Tämän kirjallisuuskatsauksen tavoitteena on kuvata mausteisiin liittyviä bakteriologisia riskejä ja niiden hallintaa sekä kuvata mausteisiin liitettyjen bakteereiden aiheuttamia ruokamyrkytysepidemioita. Työssä keskitytään vain kuivattuihin mausteisiin ja yrtteihin eikä tuoreita mausteita, nestemäisiä tai esimerkiksi suolaa käsitellä. Rajaus johtuu siitä, että kuivatut mausteet eroavat ominaisuuksiltaan huomattavasti muista maustetyypeistä. Kirjallisuuskatsauksessa keskitystään käsittelemään mausteissa esiintyviä bakteereita, vaikka mausteista voidaankin löytää muitakin mikrobeita. Mausteet on yhdistetty useisiin ruokamyrkytysepidemioihin, joiden merkittävimmät aiheuttajat ovat salmonella ja Bacillus cereus. Mausteiden globaalisuus saattaa vaikeuttaa ruokamyrkytysten selvittämistä, sillä mausteet ovat voineet mennä jakelussa useaan maahan ja näin aiheuttaa laajan kansainvälisen epidemian. Maailmalla salmonella aiheuttamat ruokamyrkytysepidemiat ovat yleisempiä, mutta Suomessa B. cereus on todennäköisempi aiheuttaja. Mausteista on myös löydetty muu muassa Escherichia colia, Staphylococcus aureusta ja Clostridium perfringenstä, mutta ne eivät ole merkittävässä roolissa mausteiden taudinaiheuttajina. Mausteiden kuivaaminen madaltaa mausteiden vesiaktiivisuutta, joka puolestaan estää bakteerien lisääntymistä. Kuivattaminen ei kuitenkaan tapa bakteereita vaan osa niistä voi säilyä elinvoimaisena. Säteilytyksen on havaittu olevan erittäin tehokas keino vähentää bakteereiden ja itiöiden määrää mausteissa. Tehokkuudestaan huolimatta säteilytystä ei käytetä, joten sen tilalle on kehitetty muita dekontaminaatiomenetelmiä muun muassa höyrykäsittelyä tai mikroaaltoja. Vaikka mausteita ei pidetä suurena uhkana ruokamyrkytysten aiheuttajana, kasvaneet RASFF-hälytykset antava viitteitä siitä, etteivät mausteet ole täysin riskittömiä. Erityisesti salmonellan lisääntyminen hälytyksissä on huolestuttavaa ihmisten terveyden kannalta