Technological and Safety Characterization of Coagulase-Negative Staphylococci Isolated from Sardinian Fermented Sausage Made by Ovine Meat

Ripened sheep sausages are widely consumed in Italy, particularly in Sardinia. Despite their driving role in flavor and color development, coagulase-negative staphylococci in these products have been rarely investigated. A total of 70 CoNS cultures isolated from Sardinian sheep sausages were characterized by rep-PCR and M13-RAPD typing and identified by 16S rDNA sequencing. S. xylosus and S. equorum accounted for more than 70% of the total isolates, whilst S. pasteuri (8.5%), S. succinus (2.8%), and S. haemolyticus (2.8%) were less represented. The genes encoding the synthesis of putrescine, tyramine, cadaverine, and histamine were evaluated by PCR. None of the strains hosted genes for decarboxylases, except one S. pasteuri strain that was potentially a tyramine-producer. Antibiotic resistance was evaluated, along with nitrate reductase, lipolytic, and proteolytic activity, in a pool of selected cultures. Resistance to the primary antibiotics was rather widespread. S. xylosus, S. equorum, and S. pasteuri strains were all resistant to amoxicillin and kanamycin. S. equorum strains were sensitive to all tested antibiotics. S. xylosus strains were all resistant to penicillin B. Conversely, all S. pasteuri strains were resistant to both ampicillin and penicillin B, and four out of five strains exhibited tetracycline resistance. The high variability in the production of sheep sausages makes the search for adjunct cultures of crucial relevance. According to this perspective, the characterization of the autochthonous CSN population represents the first step to approach a starter selection.

Probiotic bacilli incorporation in foods: is really so easy?

Foods containing probiotic bacilli spores are becoming more and more popular because of their resistance to acidic pH, low water activity, and, most importantly, heat processes. Even though spores may engage in some functions, such as immunomodulation, the majority of the beneficial characteristics are unique to vegetative cells. As matter of fact, the development of foods fortified with spores ought to even ensure the germination of the spores along the gastrointestinal tract. In this perspective, vegetative cells derived from spore germination were separately counted on a minimal medium because the traditional approach is based on the use of complex media that allows the spores to germinate independently by stimuli arising from processing or digestion. In more detail, three Bacillus spp. cultures with claimed probiotic properties were added to two entirely unrelated foods (pasta and croissants), and tolerance, as well as germination, was monitored before and after exposure to simulated GIT, as well as at the beginning and end of the products shelf life. For the first time, potential probiotic bacilli were included in a frozen ready-to-bake product. Germination appears to be prevented in this instance, and the impact of baking, matrix and cold storage on spores was examined independently. All of the parameters appeared to contribute, although further research is needed due to the unpredictable behavior exhibited by spores during freezing.

Effect of Salt Addition and Fermentation Time on Phenolics, Microbial Dynamics, Volatile Organic Compounds, and Sensory Properties of the PDO Table Olives of Gaeta (Italy)

'Oliva di Gaeta' is almost certainly the most important and well-known PDO denomination for table olives in Italy. Their production is based on a specific two-stage trade preparation called the 'Itrana' method. In this work, we investigated how variations in the duration of the initial water fermentation (i.e., 15 and 30 days) and the salt concentration (i.e., 6% and 8% NaCl) influence the chemical features, microbial dynamics, polyphenols, volatile organic compounds, and sensory features of 'Oliva di Gaeta'. The time of the addition of salt did not affect the final concentration in the brine, but a longer initial water fermentation (before salt addition) led to lower pH values. The bacterial count constantly increased until the salt addition (i.e., either 15 or 30 days), while the yeast population peaked on day 30. Generally, the two different salt concentrations did not affect the count of microorganisms at the end of fermentation, with the only exception being a higher lactic acid bacteria count for the treatment with 6% salt added at 30 days. At commercial maturity, the crucial bitter tastant oleuropein was not completely removed from the drupes, and differences in salt concentration and the length of the first-stage water fermentation did not influence its content at the end of olive curing. Richer volatile profiles of olives were detected with higher-salt treatments, while the combination of low salt and early saline treatment provided a more distinct profile. Longer initial water fermentation caused a small increase in some phenolic compounds (e.g., iso-verbascoside, verbascoside, and hydroxytyrosol-glucoside). A panel test indicated that salt application at 30 days resulted in a more "Sour" and "Bitter" taste, irrespective of the salt concentration. The low salt concentration coupled with the late saline treatment resulted in more "Fruity" notes, probably due to the higher production of esters by lactobacilli. The slightly bitter perception of the olives was consistent with the partial removal of oleuropein. Our work revealed the characteristics of the 'Itrana' method and that the variation in salt concentration and its time of application changes parameters ranging from the microbial dynamics to the sensory profile. Specifically, our data indicate that 6% NaCl coupled with a longer initial water fermentation is the most different condition: it is less effective in blocking microbial growth but, at the same time, is more potent in altering the nutritional (e.g., polyphenols) and sensorial qualities (e.g., bitterness and fruitiness) of 'Oliva di Gaeta'.

Coffee Silverskin: Chemical and Biological Risk Assessment and Health Profile for Its Potential Use in Functional Foods

The coffee supply chain is characterized by a complex network with many critical and unsustainable points producing a huge amount of waste products. Among these, coffee silverskin (CS), the only by-product of the coffee roasting phase, has an interesting chemical profile that suggests potential use as a food ingredient. However, few data on its safety are available. For this reason, the purpose of the study was to assess the occurrence of chemical and biological contaminants in CS, and the resulting risk due to its potential consumption. Essential, toxic, and rare earth elements, polycyclic aromatic hydrocarbons (PAHs), process contaminants, ochratoxin A (OTA), and pesticides residues were analyzed in three classes of samples (Coffea arabica CS, Coffea robusta CS, and their blend). Furthermore, total mesophilic bacteria count (TMBC) at 30 °C, Enterobacteriaceae, yeasts, and molds was evaluated. The risk assessment was based upon the hazard index (HI) and lifetime cancer risk (LTCR). In all varieties and blends, rare earth elements, pesticides, process contaminants, OTA, and PAHs were not detected except for chrysene, phenanthrene, and fluoranthene, which were reported at low concentrations only in the arabica CS sample. Among essential and toxic elements, As was usually the most representative in all samples. Microorganisms reported a low load, although arabica and robusta CS showed lower contamination than mixed CS. Instead, the risk assessment based on the potential consumption of CS as a food ingredient did not show either non-carcinogenic or carcinogenic risk. Overall, this study provides adequate evidence to support the safety of this by-product for its potential use in functional foods.

Late blowing defect in <em>Grottone</em> cheese: detection of clostridia and control strategies

“Grottone” is a pasta filata hard cheese produced in Campania region from cow’s milk and characterized by holes formation due to CO² development by Propionic Acid Bacteria. The contamination of raw milk with butyric acid-producing spore-forming clostridia represent a major concern for cheese producers since clostridia outgrowth may lead to the cheese late blowing defect during ripening. Detection of clostridial endospores in milk before processing and the use of antimicrobial compounds may represent an important control strategy. The present study is aimed to point out the most suitable procedure for the determination of clostridial spores in dairy samples, and to assess the inhibitory activity of several antimicrobial compounds against Cl. sporogenes. Based on results, MPN counts on Bryant and Burkey medium and CFU on RCM proved to be the most suitable protocols for routine testing. By using these procedures clostridial spores were detected in 10 out 13 milk samples and in all cheeses with late blowing defect. Within antimicrobial compounds, sodium nitrate is still the best choice for preventing late blowing, nevertheless a protective culture of Lacticaseibacillus casei proved to be a promising alternative. Nevertheless, the use of this protective culture in six Grottone cheese productions carried out at farm level, led to unsatisfactory results. Holes’ development was hampered likely for an inhibition of the PAB starter and the expected ‘Grouviera-type’ taste was not perceived by panellists. Based on results, the use of protective cultures needs to be contextualized and interactions with starters needs to be evaluated case by case.

Development of a Wet-Granulated Sourdough Multiple Starter for Direct Use

The search for sourdough starters for the direct production of baked goods with all the advantages of biological sourdough fermentation is still a crucial issue. In this study, 43 Lactic Acid Bacteria strains isolated from mature sourdoughs were evaluated for features of technological interest and tested for fermentation ability. Three microbial combinations were selected and used to produce bread. Based on GC-MS and sensory analysis, bread made by using the three combinations of strains was characterized by a more complex aroma profile with the prevalence of VOCs typical of sourdough bread. To set up the best way to keep microbial viability upon drying, the three combinations were subject to freeze-drying and wet granulation, with the latter being used for the first time for food starters’ stabilization. Wet granulation ensured optimal strains’ viability. Surprisingly, the height attained by mature sourdoughs when inoculated with wet granulated starters was constantly higher than the height reached by sourdoughs made with the same starters as fresh cells. The microbial combination E75-B72 exhibited the best performances and may represent a starter able to ensure sourdough bread production in 16 h of fermentation at 28 °C.

Comparison of droplet digital PCR vs real-time PCR for Yersinia enterocolitica detection in vegetables

Yersiniosis - the 4th most commonly reported zoonosis in the European Union - is caused by the consumption of food contaminated with the bacterium Yersinia enterocolitica. The number of human cases and contaminated food samples is probably underestimated since conventional molecular methods currently proposed for Yersinia enterocolitica detection proved to have several limitations. Critical issues associated with the detection of Yersinia enterocolitica in meat and/or meat product has already been investigated, whereas data on the possible limits of the molecular methods for Yersinia enterocolitica detection in vegetables are still lacking. According to ISO method (ISO 18867:2015), real-time polymerase chain reaction (rtPCR) should be adopted for Yersinia enterocolitica detection, even if it proved to be affected by some biases. Recently, Droplet Digital PCR (ddPCR) has been introduced as a useful tool to detect and quantify different pathogenic bacteria in complex food matrices. However, its potential application for Yersinia enterocolitica detection in vegetables has never been investigated before. In the present study two molecular platforms (rtPCR and ddPCR) were used to evaluate the pathogen's behaviour in experimentally contaminated leafy greens (Lactuca sativa L.) and to assess the rate of detection achievable after the incubation for eleven days at different temperatures. By comparing, noticeable differences emerged between the two technical approaches: only ddPCR allowed the detection of the pathogen in leafy greens when contaminated at low levels. Moreover, results of the present work highlighted the importance of length and temperature of incubation on the survival and/or the growth of Yersinia enterocolitica in vegetables: at 18 and 25 °C the concentration of the pathogen considerably decreases along incubation. Based on data, the use of rtPCR leads to an underestimation of the true prevalence of pathogenic Y. enterocolitica in vegetables, while temperature and time currently proposed for Y. enterocolitica (25 °C for 24 h), allow optimizing detection. To conclude, ddPCR may be undoubtedly proposed as a reliable alternative strategy for the quick detection of the pathogen in food samples.

Polyphenol Profiling of Chestnut Pericarp, Integument and Curing Water Extracts to Qualify These Food By-Products as a Source of Antioxidants

Plant polyphenols have beneficial antioxidant effects on human health; practices aimed at preserving their content in foods and/or reusing food by-products are encouraged. The impact of the traditional practice of the water curing procedure of chestnuts, which prevents insect/mould damage during storage, was studied to assess the release of polyphenols from the fruit. Metabolites extracted from pericarp and integument tissues or released in the medium from the water curing process were analyzed by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and electrospray-quadrupole-time of flight-mass spectrometry (ESI-qTOF-MS). This identified: (i) condensed and hydrolyzable tannins made of (epi)catechin (procyanidins) and acid ellagic units in pericarp tissues; (ii) polyphenols made of gallocatechin and catechin units condensed with gallate (prodelphinidins) in integument counterparts; (iii) metabolites resembling those reported above in the wastewater from the chestnut curing process. Comparative experiments were also performed on aqueous media recovered from fruits treated with processes involving: (i) tap water; (ii) tap water containing an antifungal Lb. pentosus strain; (iii) wastewater from a previous curing treatment. These analyses indicated that the former treatment determines a 6–7-fold higher release of polyphenols in the curing water with respect to the other ones. This event has a negative impact on the luster of treated fruits but qualifies the corresponding wastes as a source of antioxidants. Such a phenomenon does not occur in wastewater from the other curing processes, where the release of polyphenols was reduced, thus preserving the chestnut’s appearance. Polyphenol profiling measurements demonstrated that bacterial presence in water hampered the release of pericarp metabolites. This study provides a rationale to traditional processing practices on fruit appearance and qualifies the corresponding wastes as a source of bioactive compounds for other nutraceutical applications.

Dominance of S. cerevisiae Commercial Starter Strains during Greco di Tufo and Aglianico Wine Fermentations and Evaluation of Oenological Performances of Some Indigenous/Residential Strains

In order to evaluate dominance/implantation of starter cultures for wine fermentation, both commercial starters and wild strains were monitored during the fermentation of Greco di Tufo (GR) and Aglianico of Taurasi (AGL) musts. Preliminary characterization of commercial strains was carried out by several molecular markers. Five fermentations—four starter-inoculated and one spontaneous—were carried out in duplicates by using grapes from GR and AGL. Trials were monitored, and yeast cultures were isolated within the dominant microflora. Comparison of Interdelta patterns allowed to assess the real occurrence of both starters and indigenous strains. A high genetic diversity within S. cerevisiae strains was detected. In starter-led fermentations (except for few cases), in addition to the starter strains, indigenous S. cerevisiae biotypes were found, as well. Native strains isolated from replicates of the same fermentation showed different genetic profiles. Spontaneous fermentations were conducted, during the first 5 days, by non-Saccharomyces yeasts and, afterwards, by a high number (16 in the AGL and 20 in the GR) of S. cerevisiae biotypes. Indigenous biotypes isolated by GR revealed a high variability in oenological features and, in several cases, showed better performances than those recorded for commercial strains. The study further highlighted the low dominance of some commercial starter cultures. Moreover, autochthonous yeast strains proved to be sometimes more aggressive in terms of fermentation vigor in GR must, likely because better adapted to ecological and technological conditions occurring during winemaking. Finally, the use of such strains for production of autochthonous “pied de cuve” may be a useful strategy for lowering production cost of winemaking.

Therapeutic, Prophylactic, and Functional Use of Probiotics: A Current Perspective

Probiotics are considered as the twenty-first century panpharmacon due to their competent remedial power to cure from gastrointestinal dysbiosis, systematic metabolic diseases, and genetic impairments up to complicated neurodegenerative disorders. They paved the way for an innovative managing of various severe diseases through palatable food products. The probiotics' role as a "bio-therapy" increased their significance in food and medicine due to many competitive advantages over traditional treatment therapies. Their prophylactic and therapeutic potential has been assessed through hundreds of preclinical and clinical studies. In addition, the food industry employs probiotics as functional and nutraceutical ingredients to enhance the added value of food product in terms of increased health benefits. However, regardless of promising health-boosting effects, the probiotics' efficacy still needs an in-depth understanding of systematic mechanisms and factors supporting the healthy actions.

Yersinia enterocolitica detection in pork products: Evaluation of isolation protocols

Conventional methods for Yersinia enterocolitica detection in food samples are generally considered inadequate. Problems arise from the presence of the so-called "background flora", coupled to the low contamination level of the pathogen. Since, data on the microbial ecology occurring in competitive microflora are still lacking, MALDI TOF MS was used for strains 'identification after enrichment in PSB or ITC broths, and after plating on selective CIN medium at different incubation times. SYBR Green Real time PCR was used for the Y. enterocolitica strains' detection (4/O:3, 1A/O:5) in experimentally contaminated foods, as well as in naturally contaminated samples. A higher number of different bacterial genera (10 on CIN and 18 on PCA) was recorded after enrichment in PSB, whilst enrichment in ITC led to recovery of 6 and 10 genera on CIN and PCA, respectively. Yersiniaceae was the dominant family on the first day of incubation, but on the second day the percentage of isolation considerably decreased. By testing experimentally contaminated samples, substantial difficulties were encountered. The biotype 1A was always detected, whereas strain 4/O:3 proved to be poorly competitive. Based on the data, the enrichment media PSB and ITC, currently proposed for Y. enterocolitica detection, need to be improved to promote a successful pathogen's recovery.

Lactic Acid Bacteria Biota and Aroma Profile of Italian Traditional Sourdoughs From the Irpinian Area in Italy

This study identified the lactic acid bacteria (LAB) biota and the volatilome profile of 28 typical sourdoughs of Irpinia—a large area of the Campania region of Southern Italy where numerous breads are produced, even today, following the ancient procedures of sourdough fermentation and for which information on the microbiological and sensory profile is lacking in literature. For this purpose, microbial quality, LAB biodiversity, chemical, and technological characteristics, as well as aroma profile by solid-phase microextraction technique (SPME)–gas chromatography/mass spectrometry (GC/MS) of Irpinian sourdoughs were investigated. The dominant LAB microbiota was examined by both culture-dependent and culture-independent methods Polymerase Chain Reaction/Denaturing Gradient Gel Electrophoresis (PCR-DGGE). Results showed a high biodiversity in LAB community whereas the most frequent lactobacilli species recognized were Lactobacillus plantarum (ca. 22% of total LAB isolates), Lactobacillus sanfranciscensis (11%), Lactobacillus paralimentarius (8%), and Lactobacillus rossiae (6.5%), whereas LAB cocci could be mainly referred to Pediococcus pentosaceus (9.5% of total LAB isolates), Leuconostoc spp. (7.8%), and Weissella cibaria (7.7%). Sourdoughs were characterized by the dominance of one or two LAB species, thus proving that the environment influences the selection and the establishment of few key LAB species and that no specific correlation can be traced between microbial composition and geographical origin of the samples. Furthermore, although sourdoughs were characterized by different qualitative and quantitative volatile organic compound (VOC) compositions, no noticeable correlation between volatilome profile and geographical origin was found. However, it emerged that for more isolated locations, it was possible to find the existence of microbial biotypes and sensory profiles with a strong identity, thus revealing the existence of highly traditional and evocative bread recipes in those geographical contexts.

Influence of microbial communities on the chemical and sensory features of Falanghina sweet passito wines

Natural (N) as well as starter inoculated (S, inoculated with Saccharomyces cerevisiae M3-5; CZS, Candida zemplinina T13, Zygosaccharomyces bailii NS113 and Saccharomyces cerevisiae M3-5) fermentations of Falanghina must from dehydrated grape were monitored. Culture dependent analyses and amplicon-based high-throughput sequencing targeting 18S rRNA and 16S rRNA genes were used to monitor the fungal and bacterial communities (8 sampling points during 65 days). The resulting wines were subject to both sensory evaluation and volatile organic compounds analysis. Fungal community of un-inoculated musts (N) at beginning of the fermentation was mainly represented by Aureobasidium, Cladosporium, Sclerotinia, while Candida, Debaryomyces, Hanseniaspora, Metschnikowia, Pichia, Saccharomyces and Zygosaccharomyces showed a very low occurrence. The dominance of Hanseniaspora vineae and/or Hanseniaspora uvarum was clear up to 29th days of fermentation. S. cerevisiae occurred in all the phases but become dominant only at the end of the process. The odour profiles as evaluate by Quantitative Descriptive Analysis (QDA) highlighted a significant impact of the fungal populations on the olfactory profiles of the wines. Raisins, dried fruits, Sherry and liqueur were stronger in both S and CZS, while N was mostly discriminated by solvent/chemical and floral features. Outcomes underpin the impact of microbiota on the chemical and odour traits of Falanghina passito wines.

Production of probiotic bovine salami using Lactobacillus plantarum 299v as adjunct

BACKGROUND

Five probiotic lactobacilli were tested, alone or in combination with two commercial starters, to select the most suitable strain for a probiotic bovine salami production. Lactobacillus plantarum 299v was used with both starters, to make salami according to a traditional recipe. Salami obtained by using just the starters and by spontaneous fermentation, served as control. Microbial dynamics, as well as the main physico-chemical parameters, were monitored throughout ripening. The survival of probiotic 299v was confirmed by strains' tracking by means of RAPD-PCR coupled to a culture-independent approach PCR-DGGE-based.

RESULTS

The results showed a remarkable viability of the probiotic strain even after 60 days of storage. Experimental salami exhibited the same level of sensory acceptance of control salami, were hygienically safe, and characterised by pH, weight loss and microbiological loads within the ranges conventionally advocated for optimal fermented sausages.

CONCLUSION

Outcomes indicate the workable possibility of using second-quality beef cuts for probiotic salami production. © 2017 Society of Chemical Industry.

Improving in vivo conversion of oleuropein into hydroxytyrosol by oral granules containing probiotic Lactobacillus plantarum 299v and an Olea europaea standardized extract

This study reports novel food-grade granules for co-delivery of L. plantarum 299v and a standardized extract of Olea europaea leaves (Phenolea®) as oral carrier of probiotics and hydroxytyrosol. Different granule formulations containing either L. plantarum 299v (Lac), or the olive leave extract (Phe) or their combination (Lac-Phe) have been successfully produced through wet granulation employing excipients generally regarded as safe as granulating/binding agents. L. plantarum cells withstood the manufacturing process and were stable upon storage at 4 °C for more than 6 months. In vitro dissolution studies in simulated gastro-intestinal fluids showed the capability of the granules to rapidly dissolve and deliver both olive leave phenols and living L. plantarum cells. In simulated digestion conditions, Lac and Lac-Phe granules protected L. plantarum against the harsh environment of the gastro-intestinal tract. Co-administration of Lac and Phe oral granules to healthy mice provided for higher amounts of hydroxytyrosol in urines as compared to Phe granules alone, suggesting that L. plantarum 299v boosted in vivo conversion of oleuropein to hydroxytyrosol. On the other hand, PCR-assisted profiling of the Lactobacillus population in faeces obtained from mice treated with Lac or Lac plus Phe confirmed that the probiotic arrived alive to colon and was there able to exert a sort of perturbing effect on the climax colonic microflora. Overall, these results pave the way towards the development of a nutraceutical useful for combined delivery of bioactive hydroxytyrosol and probiotics to colon site.

Screening of Oxalate Degrading Lactic Acid Bacteria of Food Origin

A screening for oxalate degrading abilities was initially carried on within Lactic Acid Bacteria cultures of different food origin. Seventy-nine strains were drop-inoculated onto MRS agar plates containing calcium oxalate. By comparing colonies diameters, 31 strains were used to inoculate, in parallel, MRS and MRS modified by sodium oxalate addition. Differences in the strains’ growth were assessed by colony forming unit counts. For two strains, the growth in oxalate enriched medium was significantly higher; while, for eleven strains an opposite behaviour was recorded. Two strains – probiotic Lactobacillus rhamnosus LbGG and Enterococcus faecalis 59 – were chosen. The first strain appeared to be able to metabolize oxalate more efficiently than the other tested cultures, while strain 59 appeared unable to gather advantage by oxalates and, indeed, appeared to be inhibited by the salt presence in the medium. Outcomes revealed that higher glucose concentrations may favour oxalates utilization. In MRS with oxalate, but without glucose, citrate was completely metabolized. Evaluation along time confirmed that the oxalate degradation is more significant in presence of glucose. Outcomes may represent a good start for the development of a safe and even probiotic culture able to lower the oxalates content of food.

Characterisation, in vitro digestibility and expected glycemic index of commercial starches as uncooked ingredients

In this study native starches as ingredients (corn, rice, wheat, tapioca and potato) were characterized for microstructure, physicochemical, functional and thermal properties, in vitro digestibility and glycemic index. There was a significant variation in the granule shape and size distribution of the starches. Particle size monomodal (corn, tapioca, potato) and bimodal (rice, wheat) distribution was observed amongst the starches. The potato starch showed the biggest size granules while the rice showed the smallest. The examined properties and nutritional characteristics of starches were significantly different. Thermal properties were studied using Differential Scanning Calorimeter (DSC). DSC results showed that the transition temperatures (58.8-78.7 °C) and enthalpies of gelatinization (2.3-8.2 J/g) of the starches appeared to be greatly influenced by microstructure and chemical composition (e.g. resistant starch). Nutritional properties such as slowly digestible starch and expected glycemic index values followed the order: rice > wheat > tapioca > corn > potato. In particular, the highest resistant starch was recorded for potato starch.

Potential Role of Yeast Strains Isolated from Grapes in the Production of Taurasi DOCG

Twelve samples of Aglianico grapes, collected in different locations of the Taurasi DOCG (Appellation of Controlled and Guaranteed Origin) production area were naturally fermented in sterile containers at room temperature. A total of 70 yeast cultures were isolated from countable WL agar plates: 52 in the middle of the fermentation and 18 at the end. On the basis of ITS-RFLP analysis and ITS sequencing, all cultures collected at the end of fermentations were identified as Saccharomyces (S.) cerevisiae; while, the 52 isolates, collected after 1 week, could be referred to the following species: Metschnikowia (M.) pulcherrima; Starmerella (Star.) bacillaris; Pichia (P.) kudriavzevii; Lachancea (L.) thermotolerans; Hanseniaspora (H.) uvarum; Pseudozyma (Pseud.) aphidis; S. cerevisiae. By means of Interdelta analysis, 18 different biotypes of S. cerevisiae were retrieved. All strains were characterized for ethanol production, SO₂ resistance, H₂S development, β-glucosidasic, esterasic and antagonistic activities. Fermentation abilities of selected strains were evaluated in micro-fermentations on Aglianico must. Within non-Saccharomyces species, some cultures showed features of technological interest. Antagonistic activity was expressed by some strains of M. pulcherrima, L. thermotolerans, P. kudriavzevii, and S. cerevisiae. Strains of M. pulcherrima showed the highest β-glucosidase activity and proved to be able to produce high concentrations of succinic acid. L. thermotolerans produced both succinic and lactic acids. The lowest amount of acetic acid was produced by M. pulcherrima and L. thermotolerans; while the highest content was recorded for H. uvarum. The strain of Star. bacillaris produced the highest amount of glycerol and was able to metabolize all fructose and malic acid. Strains of M. pulcherrima and H. uvarum showed a low fermentation power (about 4%), while, L. thermotolerans, Star. Bacillaris, and P. kudriavzevii of about 10%. Significant differences were even detected for S. cerevisiae biotypes with respect to H₂S production, antagonistic activity and β-glucosidase activity as well as for the production of acetic acid, glycerol and ethanol in micro-vinification experiments.

Persistence of bacterial indicators and zoonotic pathogens in contaminated cattle wastes

BACKGROUND

Manure can provide a favourable environment for pathogens' survival. De-contamination may be conducted by extended storage, until field conditions are suitable for application to land as source of agricultural nutrients.

RESULTS

The hygienic evaluation of manure and slurry coming from a plant that collects cattle livestock wastes from a big slaughterhouse was carried out. Samples were even collected from spillages in the area around the plant. Microbial analyses highlighted the massive presence of faecal indicators in all samples: mean counts of Escherichia coli and enterococci were always above EU limits for marketable processed manure products. Cultures referable to the genus Brucella spp. were recorded in two samples of fresh manure but not in the aged ones. Conventional isolation techniques failed to detect members of the Mycobacterium genus, while by means of IS900 and F57 PCR real-time system on DNA directly extracted from environmental samples, the pathogen was detected in all cases.

CONCLUSIONS

Thoughtful design of manure storage infrastructure is critical to prevent spills and over-topping of an open structure. The documented overload situation seems to lay the basis for an ongoing environmental contamination by enteric organisms and opportunistic pathogens circuit faecal-oral route. Moreover, the type of wastes analysed during this study, namely a mixture of fresh cattle manure, bedding and rumen content, needs a longer storage period or, alternatively, of specific chemical, biological or thermal treatments for stabilization.

Mechanisms and therapeutic effectiveness of lactobacilli

The gut microbiome is not a silent ecosystem but exerts several physiological and immunological functions. For many decades, lactobacilli have been used as an effective therapy for treatment of several pathological conditions displaying an overall positive safety profile. This review summarises the mechanisms and clinical evidence supporting therapeutic efficacy of lactobacilli. We searched Pubmed/Medline using the keyword ‘Lactobacillus’. Selected papers from 1950 to 2015 were chosen on the basis of their content. Relevant clinical and experimental articles using lactobacilli as therapeutic agents have been included. Applications of lactobacilli include kidney support for renal insufficiency, pancreas health, management of metabolic imbalance, and cancer treatment and prevention. In vitro and in vivo investigations have shown that prolonged lactobacilli administration induces qualitative and quantitative modifications in the human gastrointestinal microbial ecosystem with encouraging perspectives in counteracting pathology-associated physiological and immunological changes. Few studies have highlighted the risk of translocation with subsequent sepsis and bacteraemia following probiotic administration but there is still a lack of investigations on the dose effect of these compounds. Great care is thus required in the choice of the proper Lactobacillus species, their genetic stability and the translocation risk, mainly related to inflammatory disease-induced gut mucosa enhanced permeability. Finally, we need to determine the adequate amount of bacteria to be delivered in order to achieve the best clinical efficacy decreasing the risk of side effects.

Optimised method for the analysis of phenolic compounds from caper (Capparis spinosa L.) berries and monitoring of their changes during fermentation

In this work, an ad hoc method to identify and quantify polyphenols from caper berries was developed on high-performance liquid chromatography/electrospray ionisation source/mass spectrometry (HPLC-ESI-MS). The method was applied during fermentation carried out with Lactobacillus pentosus OM13 (Trial S) and without starter (Trial C). A total of five polyphenols were identified. All samples contained high concentrations of rutin. Epicatechin was found in untreated fruits, on the contrary quercetin was detected during fermentation. Trial S was characterised by a more rapid acidification and lower levels of spoilage microorganisms than Trial C. L. pentosus dominated among the microbial community of both trials and the highest biodiversity, in terms of strains, was displayed by Trial C. Aureobasidium pullulans was the only yeast species found. The analytical method proposed allowed a high polyphenolic compound recovery from untreated and processed caper berries in short time. The starter culture reduced the bitter taste of the final product.

Effect of yeast strain and some nutritional factors on tannin composition and potential astringency of model wines

Nine Saccharomyces cerevisiae cultures, isolated from different sources, were tested for their ability to reduce tannins reactive towards salivary proteins, and potentially responsible for wine astringency. Strains were preliminary genetically characterized and evaluated for physiological features of technological interest. Laboratory-scale fermentations were performed in three synthetic media: CT) containing enological grape tannin; CTP) CT supplemented with organic nitrogen sources; CTPV) CTP supplemented with vitamins. Adsorption of total tannins, tannins reactive towards salivary proteins, yellow pigments, phenolics having antioxidant activity, and total phenols, characterizing the enological tannin, was determined by spectrophotometric methods after fermentation. The presence of vitamins and peptones in musts greatly influenced the adsorption of tannins reactive towards salivary proteins (4.24 g/L gallic acid equivalent), thus promoting the reduction of the potential astringency of model wines. With reference to the different phenolic classes, yeast strains showed different adsorption abilities. From a technological point of view, the yeast choice proved to be crucial in determining changes in gustative and mouthfeel profile of red wines and may assist winemakers to modulate colour and astringency of wine.

Optimization of water curing for the preservation of chestnuts (Castanea sativa Mill.) and evaluation of microbial dynamics during process

Chestnuts are very perishable fruits, whose quality may be compromised during postharvest handling. Damage can be caused both by insects and fungi. Water curing, a commonly used postharvest method, is based on soaking fruits in water typically for about one week. Factors that affect effectiveness of water curing have only been explained partially. A decrease in pH, likely imputable to a light fermentation caused by lactic acid bacteria, may inhibit the growth of moulds. In this study a Lactobacillus pentosus strain was selected for its ability to inhibit fungi, and used as a starter culture during water curing. As second goal, a reduction of the environmental impact of the process was evaluated by using water that had been re-cycled from a previous curing treatment. Experiments were performed on pilot as well as on farm scale. In all trials, microbial dynamics were evaluated by means of a polyphasic approach including conventional and molecular-based analyses. According to results, the employment of an adjunct culture appears as a very promising opportunity. Even if no reduction in the duration of the process was achieved, waters exhibited a minor microbial complexity and fruits did not lose the natural lustre after the process.

Comparison of the effects of hyaluronidase and hyaluronic acid on probiotics growth

Background

Hyaluronic acid has several clinical applications. Recent evidences suggested antimicrobial properties against several pathogens. The aim of the present survey was to evaluate the effect of hyaluronic acid, alone or in combination with hyaluronidase, on protechnological or probiotic strains.

Results

The role of hyaluronic acid and hyaluronidase on in vitro growth rate of different lactic acid bacteria was investigated. Standard methods revealed that low concentrations of hyaluronic acid (0.5-0.125 mg ml^-1), and hyaluronidase at fixed concentration (1.6 mg ml^-1), resulted in an increased bacterial strains growth up to 72 hours whereas higher concentrations of the acid (2 and 1 mg ml^-1), and hyaluronidase at the same fixed concentration, reduced the bacterial growth.

Conclusions

Observations might suggest a possible protective role of both hyaluronidase and low doses of hyaluronic acid towards some strains, supporting their in vivo proliferation and engraftment after oral administration. Hyaluronidase introduction into growth medium greatly enhanced the bacterial growth up to 72 hours.

Effect of chestnut extract and chestnut fiber on viability of potential probiotic Lactobacillus strains under gastrointestinal tract conditions

The main challenge to probiotics, during their passage through the gastrointestinal tract, are the acidic gastric secretions of the stomach, and the bile salts released into the duodenum. The survival of the strains, in this phase, is strongly influenced by the food used for their delivery. This work is part of a project studying the development of novel food processes, based on the use of chestnuts from cultivar "Castagna di Montella". In detail, the effect of indigestible chestnut fiber and of chestnut extract on the viability of selected lactic acid bacteria strains was evaluated. Among 28 cultures, twelve strains were selected, on the basis of tolerance to low pH values and bile salts, and submitted to exposition to simulated gastric or bile juice in presence of chestnut extract with or without immobilization in chestnut fiber. The presence of chestnut extract proved to play a significant role on the gastric tolerance improvement of lactobacilli. The recorded protective effect could not be simply related to the starch or reducing sugars content. RP-HPLC demonstrated that in the chestnut flour, there are one or more hydrophobic peptides or oligopeptides, which specifically offer a marked resistance to simulated gastric juice, albeit present at low concentration. These beneficial effects proved to be dependent by the cultivar used to produce the flour.

Short communication: technological and genotypic comparison between Streptococcus macedonicus and Streptococcus thermophilus strains coming from the same dairy environment

The species Streptococcus thermophilus is widely used for the preparation of several dairy products, and its technological contribution is clear. On the other hand, although Streptococcus macedonicus was first described more than 10 yr ago and, despite the scientific interest around this issue, the exact role of Strep. macedonicus in cheese making has yet to be clarified. In this study, 121 strains belonging to both species and isolated from the same dairy environment were genetically characterized by random amplification of polymorphic DNA (RAPD)-PCR and compared for the main biochemical features of technological interest, such as acid production, galactose utilization, citrate metabolism, exopolysaccharide production, and lipolytic, ureolytic, exocellular proteolytic, and decarboxylasic activities. Analysis by RAPD-PCR highlighted a remarkable genotypic heterogeneity among strains in both species, and, at a similarity level of 78%, all the isolates and reference strains of Strep. thermophilus grouped together and were well separated from the strains of Strep. macedonicus, confirming that these 2 species are different microbial entities. Comparison between genetic and phenotypic or biotechnological data did not reveal any relationships.

Use of selected autochthonous lactic acid bacteria for Spanish-style table olive fermentation

The present work presents a successful attempt to achieve an enhanced and more predictable fermentation process in Spanish-style green olive technology by selection and use of autochthonous starter cultures. During the first phase of this work, two Spanish-like fermentations of green table olives of cultivar (cv) "Nocellara del Belice", coming from irrigated and not irrigated fields, were monitored, in order to highlight the best agricultural conditions for drupe production and to isolate lactic acid bacteria strains with relevant technological properties. Among 88 identified isolates, one Lactobacillus pentosus strain showed remarkable biochemical features and high acidification rate in synthetic brine. In the second phase, the selected strain was used as starter culture in three different trials to establish the best conditions for its use. Microbial counting, as well as starter tracking by M13 RAPD-PCR, reflected the optimal adaptation of the strain to the environment. Spontaneous fermentation needed a 14-day long lag phase to reach the same population as the inoculated trials. Moreover, sensory traits of table olives obtained with adjunct culture showed better characteristics compared to those processed in the other trials, in particular concerning the presence of off-odours.

Abstract 1813: Implementation and outcomes of a community-based educational program in colorectal cancer prevention

Background: Cancer is the second most common cause of death in Puerto Rico (PR) after heart disease. Colorectal cancer (CRC) is the second most commonly diagnosed cancer among both men and women. The cancer screening guidelines given by the American Cancer Society indicate that adults should begin CRC screening at the age of 50. Although self-reported CRC screening from 1997 to 2006 have showed an increase in PR, CRC screening trends are lower than in the United States. With low screening rates and high CRC mortality in PR, health promotion programs aimed at education and prevention are needed.

Methods: The purpose of this study was to evaluate a community-based educational program (Train-the-Trainer – TTTP) to increase knowledge and awareness of prevention about CRC in PR. The TTTP consisted of a formal didactic and hands-on seminar where participants were given didactic information and were trained to become trainers in CRC prevention. The TTTP was open to any adult, who was willing to become a trainer and committed to present the information in another forum using the materials provided at the TTTP. For the evaluation of this project, three main components were measured: (1) the Train the Trainers’ sessions; (2) the Participants’ Community Educational Sessions; and (3) the participant's experience delivering the training intervention. A total of five different questionnaires were design for the evaluation process of each component. Both qualitative and quantitative methods were used to collect data. Evaluations of outcomes were measured within 60-days of the TTT session.

Results: Pre- and post-tests were given to the participants of the Train-the-Trainer session (N=115). There was a significant difference in the scores for the pre-test (mean=10.56, SD=2.57) and the post-test (mean=11.43, SD=1.83); t(96)=−4.68, p&lt; 0.001); suggesting an augmentation in knowledge. Overall the participants from the community educational sessions (N=680) evaluated the program to be a success indicating that it provided them with knowledge, resources, and motivation to be screened for colorectal cancer, with 69.9% indicating their willingness to obtain a colonoscopy in the future. The trainer-to-trainee ratio was 1:6, with each participant of the TTTP training an average of 6 individuals from their own community within a 60-day period.

Conclusion: The Puerto Rico CRC TTTP was effective in capacitating individuals to become trainers in their respective communities. The TTTP was effective in increasing knowledge of CRC prevention strategies and successfully reached members of the community. Implementation of a community-based program designed to develop trainers in CRC prevention demonstrated to be feasible and effective. Community based training programs are an alternative to promote CRC education and awareness in PR and may impact CRC screening rates, with subsequent decreases in mortality.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1813. doi:10.1158/1538-7445.AM2011-1813

Could halophilic archaea improve the traditional salted anchovies (Engraulis encrasicholus L.) safety and quality?

AIMS

The positive influence of two selected extremely halophilic archaea strains in the production of salted anchovies (Engraulis encrasicolus, L., 1758) was highlighted.

METHODS AND RESULTS

Anchovies produced with salt artificially contaminated with halophiles exhibited lower loads of staphylococci, Enterobacteriaceae and lactic acid bacteria, and a reduced content of histamine as well as an improved organoleptic acceptance.

CONCLUSIONS

The findings of this survey are expected to enhance the safety of salted anchovies, with regard to the histamine formation during ripening, and to improve the sensory attributes of this product.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study represents the first report on the positive influence of halophilic archaea in traditional salted anchovies production, thus suggesting new perspectives about a conscious employment of properly selected haloarchaea strains in this traditional manufacture.

Genetic Diversity of a Natural Population of Rhizobium leguminosarum bv. viciae Nodulating Plants of Vicia faba in the Vesuvian Area

A total of 98 rhizobial strains, isolated during the winter of the years 2003 (35 isolates), 2004 (33 isolates), and 2005 (30 isolates) were analyzed to determine the genetic diversity of the natural population nodulating Vicia faba plants and to identify dominant genotypes. All isolates were identified as Rhizobium leguminosarum bv. viciae by biovar-specific polymerase chain reaction amplification of the nodC gene. Intraspecific DNA polymorphism was evaluated through the restriction endonucleases analysis combined with pulsed-field gel electrophoresis. Four genotypes characterized 53% of the isolates, showing a high occurrence; moreover, they were recovered over the 3 years, thus showing a lasting persistence in the soil, which could mean a high degree of saprophytic competitiveness. The richness, diversity, and dominance indexes of genotypes were calculated to monitor the evolution of the rhizobial population during the 3 years. The genetic diversity of the analyzed strains decreased along the 3 years. In fact, the biodiversity index H' decreased from 2.6 in the first and second year to 1.9 in the third year; probably, as a result of bean monocropping, specific genotypes of Rh. leguminosarum bv. viciae were naturally selected.

Fennel waste-based films suitable for protecting cultivations

Biodegradable, flexible, and moisture-resistant films were obtained by recycling fennel waste and adding to fennel homogenates the bean protein phaseolin that was modified or not modified by the enzyme transglutaminase. All films were analyzed for their morphology, mechanical properties, water vapor permeability, and susceptibility to biodegradation under soil-like conditions. Our experiments showed that transglutaminase treatment of the phaseolin-containing fennel waste homogenates allowed us to obtain films comparable in their mechanical properties and water vapor permeability to the commercial films Ecoflex and Mater-Bi. Furthermore, biodegradability tests demonstrated that the presence of the enzyme in the film-casting sample significantly influences the integrity of such a product that lasts longer than films obtained either with fennel waste alone or with a mixture of fennel waste and phaseolin. These findings indicate the fennel-phaseolin film prepared in the presence of transglutaminase to be a promising candidate for a new environmentally friendly mulching bioplastic.

Fluorescence in situ hybridisation detection of Lactobacillus plantarum group on olives to be used in natural fermentations

At present there are very few studies on the bacterial diversity of olives and on the importance of the microbial species for the fermentation of olives aimed to table olives production. Most of the authors report on the occurrence of Lactobacillus plantarum as principal member of these communities or at least as the species responsible for the fermentation. In this study, fluorescence in situ hybridisation (FISH) with 16S rRNA probes was used to evaluate the occurrence of L. plantarum in olives. A 18-bp oligonucleotide probe was used in FISH experiments to evaluate the specificity of detection among Lactobacillus species. The probe was tested against 30 Lactobacillus species and appeared to be specific for L. plantarum, L. paraplantarum and L. pentosus. The probe was then used to investigate the occurrence of these species in 25 samples of olives (cultivar "Leccino") collected in Campania region (Southern Italy). The olives were washed in a saline solution and the suspensions were then analysed by FISH and observed by fluorescence microscopy. No hybridisation signal was detected in at least 30 fields of observation when the L. plantarum-specific probe was used, probably due to the low sensitivity of the FISH method. Olive samples were plated on Rogosa agar and about 40% of the samples did not give growth after 5 days. When colony growth was observed, bulk cells from Rogosa agar plates were collected and analysed by DNA extraction followed by 16S rDNA Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The different microbial species were identified by direct sequencing of DGGE bands. Leuconostoc pseudomesenteroides was the most frequently found species, occurring in more than 50% of the samples that had shown growth on Rogosa agar. The closest relatives of the species of the genera: Leuconostoc, Pediococcus, Pseudomonas and Raoultella were also identified suggesting that guided fermentation by using selected LAB starters is advisable for a safe and desired table olives production.

Staphylococcus aureus and staphylococcal enterotoxin A in breaded chicken products: detection and behavior during the cooking process

In this study we examined the presence of Staphylococcus aureus and staphylococcal enterotoxin A (SEA) in 20 industrial breaded chicken products obtained from different retail butchers and supermarket stores in Italy. The levels of contamination in the products analyzed were quite low, although the pH values and water activities (a(w)) in the samples considered were in ranges favorable for S. aureus growth. As demonstrated by phenotypic and molecular characterization, in spite of the high percentage of coagulase-positive Staphylococcus strains, only three strains could be referred to the species S. aureus. Moreover, all the strains were negative in PCR assays targeting staphylococcal enterotoxin genes (seA to seE, seG to seJ, and seM to seO), as well as the toxic shock syndrome toxin 1 gene, and no SEA was detected in the retail breaded chicken samples analyzed by a reversed passive latex agglutination assay or by Western blotting. Hence, we evaluated the thermal resistance of two strains of SEA-producing S. aureus in a laboratory-scale preparation of precooked breaded chicken cutlets. The heat treatment employed in the manufacture determined the inactivation of S. aureus cells, but the preformed SEA remained active during product storage at 4 degrees C. The presence of the staphylococci and, in particular, of S. aureus in the retail breaded chicken products analyzed is a potential health risk for consumers since the pH and a(w) values of these kinds of products are favorable for S. aureus growth. The thermal process used during their manufacture can limit staphylococcal contamination but cannot eliminate preformed toxins.

Evaluation of microbial diversity during the manufacture of Fior di Latte di Agerola, a traditional raw milk pasta-filata cheese of the Naples area

Microbial diversity of the raw milk for the production of Fior di Latte di Agerola and its changes during cheesemaking were studied. Viable counts showed that at the end of curd ripening, loads of lactic acid bacteria, both mesophilic and thermophilic rods and cocci, higher than those commonly evidenced in similar cheeses produced by using natural or commercial starters, were detected. Identification of 272 isolates, supported by molecular diagnostic aids, evidenced representative cultures of a high number of bacterial taxa of interest as participating in the process, although most of the isolates belonged to Lactococcus lactis and Lactobacillus helveticus species. RAPD-PCR and REA-PFGE biotyping were performed for the isolates of the above species and it was shown that most of the strains isolated from the raw milk occurred during the whole cheesemaking process, and an active role of these strains in the fermentation was supposed. The results offer further proof of the importance of the raw milk as source of technologically interesting strains of lactic acid bacteria capable of driving the fermentation of traditional cheeses.