Francesco Fancello

Comparison of bacteriocins production from Enterococcus faecium strains in cheese whey and optimised commercial MRS medium

The production of bacteriocins from cheap substrates could be useful for many food industrial applications. This study aimed at determining the conditions needed for optimal production of enterocins SD1, SD2, SD3 and SD4 secreted by Enterococcus faecium strains SD1, SD2, SD3 and SD4, respectively. To our knowledge, this is the first use of cheese whey—a low-cost milk by-product—as a substrate for bacteriocin production by E. faecium; skimmed milk and MRS broths were used as reference media. This cheese manufacturing residue proved to be a promising substrate for the production of bacteriocins. However, the levels of secreted antimicrobial compounds were lower than those achieved by E. faecium strains in MRS broth. Bacteriocin production was affected strongly by physical and chemical factors such as growth temperature, time of incubation, pH, and the chemical composition of the culture medium. The optimal temperature and time of incubation supporting the highest bacteriocin production was determined for each strain. Different types, sources and amounts of organic nitrogen, sugar, and inorganic salts played an essential role in bacteriocin secretion. E. faecium strains SD1 and SD2—producing high bacteriocin levels both in cheese whey and skimmed milk—could be of great interest for potential applications in cheese-making.

Antimicrobial Activity against Beneficial Microorganisms and Chemical Composition of Essential Oil of Mentha suaveolens ssp. insularis Grown in Sardinia

UNLABELLED The aim of this work was to determine the chemical constituents and in vitro antimicrobial activity of the essential oil (EO) of the aerial parts of Mentha sueveolens spp. insularis grown in Sardinia (Italy) against probiotic and starter microorganisms. The gas chromatography-mass spectrometry (GC-MS) analysis allowed to identified 34 compounds, most of oxygenated monoterpene compounds (82.5%) and among them, pulegone was found as major compound (46.5%). The agar diffusion test carried out employing the EO of Mentha suaveolens spp. insularis showed a low antibacterial activity, in particular no action was noticed for probiotic bacteria belonging to lactic acid bacteria groups, whereas almost all yeasts strains tested were inhibited. The automated microtitter dilution assay showed a clear effect at increasing concentration of EO on the specific growth rate (μ) and extension of the lag phase (λ) only for S. xylosus SA23 among bacteria and for Saccharomyces cerevisiae, Tetrapisispora phaffii CBS 4417, Metschnikowia pulcherrima, and Candida zemplinina among yeasts. Results obtained in this work allow us to broaden the knowledge on the effect of EOs on probiotic and food-related microorganisms. PRACTICAL APPLICATION Mentha suaveolens spp. insularis may be used in combination with probiotic bacteria into the food matrix or encapsulated in coating and edible films for food preservation.

Microbiological characterization using combined culture dependent and independent approaches of Casizolu pasta filata cheese.

Casizolu is a traditional Sardinian (Italy) pasta filata cheese made with cow raw milk belonging to Sardo‐Modicana and/or Bruno‐Sarda breeds added with natural whey starter. This work aims to describe the traditional technology of this product and to evaluate the microbial groups/species involved in the first month of ripening.

Influence of Myrtle Juice and Syrup on Microbiological, Physicochemicaland Sensory Features of Goat?s Milk Yogurt Made with Indigenous StarterCulture

This study evaluated the effect of Myrtle Juice (MJ) and Syrup (MS) on microbiological, physicochemical and sensory features in goat milk yogurt fermented by indigenous Streptococcus thermophilus and Lactobacillus delbruekii subsp. bulgaricus during 30 days of storage. Generally, in all samples, the high LAB number at the end of incubation and the pH values ranging from 4.1 to 4.6 indicates a good effectiveness of the used starter on fermentation process. L. delbrueckii subsp. bulgaricus compared to S. thermophilus was the most abundant in yogurt with MJ (YMJ) after 30 days of storage compared to YMS. On the contrary, S. thermophilus demonstrated the highest viability (7 log cfu/g) in the yogurt with MS throughout the storage period. Spoilage and pathogens microorganisms were absent in fresh products and during the storage period. Overall, physicochemical where very similar in all samples, Myrtle juice addition has positively influenced the increase of the lactic acid L(+), acetaldehyde and Free Fatty Acids (FFAs) content. All samples resulted well for flavor and acidity attributes as well as astringency parameter is highly expressed in the YMJ.

Walkability Explorer: Application to a Case-Study

In a few recent papers we presented a methodology and the related planning and design support tool, Walkability Explorer, for the evaluation of walkability of places which are relevant for people’s capabilities. The method is an attempt to move beyond the known approaches to evaluating walkability based on the analysis of proximity to urban places and on macro urban and socioeconomic factors, because it conceptualises walkability as the effective capability to walk offered by the environment thanks to micro-urban characteristics. It evaluates how the urban environment is conducive to walk by combining three elements: the destinations/opportunities reachable by foot, their walking distance and the quality of the path to these destinations. Following this approach, here we present and discuss an example assessment of walkability for the city of Alghero (Italy).

Testicular development in male lambs prenatally exposed to a high‐starch diet

Maternal nutrition during critical gestation periods impacts on offspring in later life; effects of high‐starch maternal diet on testicular development in lambs were addressed. Dairy ewes were fed diets providing either 27% (Starch, S) or 11% (Fiber, F) of starch from mating to lambing (∼147 days; S147, F147) or for the last 75 days of gestation (S75, F75). Testes of single male lambs were measured and then sampled for histological and gene expression analyses at selected ages. Testicular dimensions and weight were similar among groups, but the total area of seminiferous tubules increased with age and tended to be higher (p = 0.057) in lambs from starch‐ than fiber‐fed ewes. Sertoli and germ cells number increased with age, but was not influenced by maternal diet. Transcript abundances of androgen receptor (AR), insulin‐like growth factor 1 (IGF1), and hydroxysteroid (17‐beta) dehydrogenase 3 (HSD17B3) was similar between S147 and F147 lambs (p > 0.1). Abundance of luteinizing hormone/choriogonadotropin receptor (LHCGR) and steroidogenic acute regulatory protein (STAR) was higher in young vs older lambs, whereas insulin‐like growth factor 2 (IGF2) levels increased with age. The expression of vascular endothelial growth factor A (VEGFA), Anti‐Müllerian hormone (AMH), IGF1, follicle stimulating hormone receptor (FSHR), and insulin‐like growth factor 2 receptor (IGF2R) was not influenced by maternal diet or lamb age (p > 0.1). In conclusion, a high‐starch maternal diet did not influence gene expression, but may have affected testicular structure in infant offspring, as seen by an increase in the total area of seminiferous tubules.

Isolation and characterization of microorganisms and volatiles associated with Moroccan saffron during different processing treatments

Saffron may be spoiled by a variety of microorganisms during cultivation, harvesting, and post harvesting. As saffron can be dried and stored in different ways, this preliminary study explored the natural microbiota present in Moroccan saffron when subjected to different drying techniques. An analysis of the carotenoid-derived volatiles present in the saffron was also carried out. The culturable microbiota of the saffron samples dried using different methods, namely in the shade (also called natural), in the sun, or in the oven, were studied using classical and molecular approaches. The effect of the drying methods on head-space chemical volatiles was also determined. Eighty-two isolates grown in the different culture media were chosen from the colonies, and genotype analysis grouped the microorganisms into 58 clusters, revealing a wide diversity. Out of the 82 isolates, 75 belonged to the Bacillaceae family. The other isolates were distributed within the Dietziaceae, Paenibacillaceae and Carnobacteriaceae families. The dominant species was Bacillus simplex, which was detected in all samples, regardless of the drying method used. Lysinibacillus macroides was dominant in the sun-dried saffron. No pathogens were isolated, but an isolate belonging to Dietzia maris, a potential human pathogenic species, was detected. The biodiversity indexes were linked to the drying method and generally decreased as the intensity of the treatment increased. The results of this preliminary work show that the different drying methods strongly influenced the microbiota and affect the saffron volatile profile. Further analysis will be needed to determine possible effects of selected microbiota on saffron volatiles.

Multi-Omic Biogeography of the Gastrointestinal Microbiota of a Pre-Weaned Lamb

The digestive functions of the pre-weaned lamb gastrointestinal tracts (GITs) have been the subject of much research in recent years, but the microbial and host functions underlying these complex processes remain largely unknown. Here, we undertook a proof-of-principle metaproteogenomic investigation on luminal and mucosal samples collected from 10 GITs of a 30-day-old pre-weaned lamb. We demonstrate that the analysis of the diverse ecological niches along the GITs can reveal microbiota composition and metabolic functions, although low amounts of microbial proteins could be identified in the small intestinal and mucosal samples. Our data suggest that a 30-day lamb has already developed mature microbial functions in the forestomachs, while the effect of the milky diet appears to be more evident in the remaining GITs. We also report the distribution and the relative abundance of the host functions, active at the GIT level, with a special focus on those involved in digestive processes. In conclusion, this pilot study supports the suitability of a metaproteogenomic approach to the characterization of microbial and host functions of the lamb GITs, opening the way to further studies aimed at investigating the impact of early dietary interventions on the GIT microbiota of small ruminants.

Essential oils from three species of Mentha harvested in Sardinia : chemical characterization and evaluation of their biological activity

ABSTRACT The chemical composition, antimicrobial activity, and antioxidant activity of Mentha (M.) requienii, M. pulegium L., and M. aquatica (L.) Huds from Sardinia, Italy, were tested. The chemical composition was determined by Gas Chromatography-Mass Spectrometry (GC-MS) and GC-Flame Ionization Detector (GC-FID) analyses. The antiradical activity was assessed by 2,2-Diphenyl-1-picrylhydrazyl and antioxidant capacity assay (ABTS) assay and minimal inhibition concentration was determined by microdilution broth analysis. The major components found in M. requienii EO were pulegone, menthone, and limonene; similarly, the major components of M. pulegium EO were pulegone and iso-menthone. By contrast, the major components of the essential oil (EO) from M. aquatica are terpinyl acetate and eucalyptol. The antioxidant activity of M. aquatica EO was higher than that of M. requienii and M. pulegium. The EO from M. requienii had good antifungal and antioxidant activities. In the concentration range tested, the mint EOs did not show any antibacterial activity against Staphylococcus aureus 20231 Deutsche SammLung von Mikroorganismen und Zellkulturen (DSMZ), Salmonella enterica subsp. bongori serovar 66:z41:- 13772 DSMZ, and four strains of Listeria monocytogenes. Lactic acid bacteria (LAB) strains were not inhibited by the EOs tested, with the exception of Lactobacillus brevis, which showed slight sensitivity to M. pulegium and M. requenii EOs. Yeast strains were in general sensitive to the different Mentha EOs tested and were species and strain dependent.