Improvement of raw milk cheese hygiene through the selection of starter and non-starter lactic acid bacteria: The successful case of pdo pecorino siciliano cheese

This review article focuses on the technological aspects and microbiological critical points of pressed-cooked cheeses processed from raw ewe’s milk without the inoculation of starter cultures, in particular “Pecorino” cheese typology produced in Italy. After showing the composition of the biofilms adhering to the surface of the traditional dairy equipment (mainly wooden vat used to collect milk) and the microbiological characteristics of PDO Pecorino Siciliano cheese manufactured throughout Sicily, this cheese is taken as a case study to develop a strategy to improve its hygienic and safety characteristics. Basically, the natural lactic acid bacterial populations of fresh and ripened cheeses were characterized to select an autochthonous starter and non-starter cultures to stabilize the microbial community of PDO Pecorino Siciliano cheese. These bacteria were applied at a small scale level to prove their in situ efficacy, and finally introduced within the consortium for protection and promotion of this cheese to disseminate their performances to all dairy factories. The innovation in PDO Pecorino Siciliano cheese production was proven to be respectful of the traditional protocol, the final cheeses preserved their typicality, and the general cheese safety was improved. An overview of the future research prospects is also reported

A non-invasive approach to estimate the energetic requirements of an increasing seabird population in a perturbed marine ecosystem

This is the author accepted manuscript. The final version is available from Springer Nature via the DOI in this record.There is a growing desire to integrate the food requirements of predators living in marine ecosystems impacted by humans into sustainable fisheries management. We used non- invasive video-recording, photography and focal observations to build time-energy budget models and to directly estimate the fish mass delivered to chicks by adult greater crested terns Thalasseus bergii breeding in the Benguela ecosystem. Mean modelled adult daily food intake increased from 140.9 g·d−1 of anchovy Engraulis capensis during incubation to 171.7g·d−1 and 189.2 g·d−1 when provisioning small and large chicks, respectively. Modelled prey intake expected to be returned to chicks was 58.3 g·d−1 (95% credible intervals: 44.9–75.8 g·d−1) over the entire growth period. Based on our observations, chicks were fed 19.9 g·d−1 (17.2–23.0 g·d−1) to 45.1 g·d−1 (34.6–58.7 g·d−1 25 ) of anchovy during early and late provisioning, respectively. Greater crested terns have lower energetic requirements at the individual (range: 15–34%) and population level (range: 1–7%) than the other Benguela endemic seabirds that feed on forage fish. These modest requirements – based on a small body size and low flight costs – coupled with foraging plasticity have allowed greater crested terns to cope with changing prey availability, unlike the other seabirds species using the same exploited prey base.Our research was supported by a Department of Science and Technology-National Research Foundation Centre of Excellence grant to the FitzPatrick Institute of African Ornithology, the Leiden Conservation Foundation (RBS) and our institutes. Robben Island Museum provided logistical support and access to the tern colonies

Microbial ecology of retail ready-to-eat escarole and red chicory sold in Palermo City, Italy

Background: Ready-To-Eat (RTE) foods include any edible food that is commonly consumed raw. This study aimed at evaluation of microbial ecology of retail RTE escarole and red chicory sold in Palermo city, Italy. Methods: A total of 32 mono-varietal RTE samples, including escarole (n=16) and red chicory (n=16) samples were obtained from Palermo, Italy. Both RTE vegetables at expiry date were analyzed to quantify spoilage bacteria, pathogenic bacteria, and yeast. All different colonies were isolated and identified on the basis of phenotypic characteristics and genetic polymorphisms by random amplification of polymorphic DNA-Polymerase Chain Reaction (PCR) and further genotype by sequencing the 16S rRNA gene. The statistical analysis was conducted with SAS 9.2 software (Statistical Analysis System Institute Inc., Cary, NC, USA). Results: The level of Listeria monocytogenes and coagulase-positive staphylococci were below the detection. Total microbial counts were above 8 log10 colony forming unit/g in RTE red chicory, while they were about 1 log cycle lower in escarole. In general, escarole showed lower levels for all microbial groups than red chicory with the exception of the total yeast. A total of 13 strains were identified into ten species belonging to six genera as Bacillus, Erwinia, Pantoea, Pseudomonas, Microbacterium, and Rahnella. The most numerous identified genera were Pseudomonas and Pantoea. Conclusion: This work pointed out the relevance of implementing good hygiene practices during processing in order to prolong quality parameters and acceptability of mono-varietal salads

The costs of kleptoparasitism: a study of mixed-species seabird breeding colonies

This is the author accepted manuscript. The final version is available from OUP via the DOI in this record.Mixed-species assemblages are common in nature, providing mutual benefits to associating species including anti-predator advantages or resource facilitation. However, associating with other species may also impose costs through kleptoparasitism (food theft). Identification of these costs, and how they vary when different species breed alongside one another, is essential to understand the payoffs of mixed-species assemblages. We explore the costs of kleptoparasitism for greater crested terns Thalasseus bergii provisioning offspring at a single-species colony, where individuals suffer kleptoparasitism from conspecifics, and at a mixed colony where terns breed alongside Hartlaub’s gulls Chroicocephalus hartlaubii and are vulnerable to both intra and interspecific kleptoparasitism. Gull presence likely contributes to increases in both kleptoparasitic attacks and the proportion of prey lost or stolen during provisioning, relative to the single-species colony. Provisioning adults suffered additional energetic costs in response to gull kleptoparasitism, requiring more attempts to deliver prey, taking longer to do so, and swallowing more prey (to the detriment of their offspring). Gulls also appear to increase the duration of tern vulnerability to kleptoparasitism, because they continued to steal food from adults and chicks after precocial chicks left the nest, when intraspecific kleptoparasitism is negligible. Terns breeding in a mixed colony, therefore, suffer direct and indirect costs through decreased provisioning and increased provisioning effort, which may ultimately affect reproductive success, resulting in colony decline where kleptoparasitism is frequent. This study illustrates how forming a mixed-species seabird breeding assemblage has costs as well as benefits, potentially fluctuating between a parasitic and a mutualistic relationship.This work was supported by a Department of Science and TechnologyCentre of Excellence grant to the FitzPatrick Institute of African Ornithology. R.B.S.  was supported by a fellowship from the Leiden Conservation Foundation. This research was approved by SANParks (CONM1182), the Department of Environmental Affairs (RES2013/24, RES2014/83, and RES2015/65) and the animal ethics committee of the University of Cape Town (2013/V3/TC)

A Multivariate Approach to Study the Bacterial Diversity Associated to the Wooden Shelves Used for Aging Traditional Sicilian Cheeses

The present study was carried to correlate the microbial diversity of the biofilms developed on the wooden boards used for aging traditional Sicilian cheeses with cheese typology. To this end, the microbial diversity of the shelves in contact with the cheeses PDO Pecorino Siciliano, PDO Piacentinu Ennese, and TAP Caciocavallo Palermitano, during ripening, was evaluated by a multivariate statistical approach. The shelf biofilms of this study were previously analyzed for their microbial composition, but no correlation between biodiversity and cheese type was investigated. Canonical discriminant analysis confirmed a cheese typology effect on the microbial loads of the wooden shelves investigated. Regarding the plate count data, the centroids of different cheeses were statistically distant from one another. This analysis also showed a good graphic separation of data regarding bacterial order operational taxonomy units (OTUs). Thus, the microbiological differences imputed to the cheese typologies were not affected by the environmental conditions of the facilities. Furthermore, wooden shelf lactic acid bacteria (LAB) were investigated for their ability to inhibit the main dairy pathogens. Although inhibitors were mainly enterococci, P. pentosaceus WS287 and W. paramesenteroides WS581 showed the highest inhibition activity, indicating their possible application to control the undesired bacteria in situ

Influence of Biochar on the Properties of Antibacterial PBAT/Carvacrol Films

In recent years, there has been an increasing interest in antibacterial biopolymeric films. Among the different approaches for tuning the release kinetic of antibacterial compounds, the use of natural fillers allows for this purpose while optimizing the processability and the mechanical properties of the products. In this work, the effect of three different concentrations of biochar (BC) was investigated on the morphological, rheological, mechanical, and thermal properties of Polybutylene adipate terephthalate/Carvacrol/BC (PBAT/CV/BC) ternary biocomposites. The films were fabricated by means of melt mixing and compression molding and compared to PBAT/BC samples. The carvacrol kinetic release was evaluated as a function of the BC concentration in the ternary system. Results highlighted that BC allows tuning the properties of PBAT and of PBAT/CV samples and modifying the release kinetic of CV. Finally, the antimicrobial analysis revealed that PBAT/CV films exhibited excellent antimicrobial properties against Escherichia coli, Listeria monocytogenes, Salmonella Enteritidis, and Staphylococcus aureus

In vitro evaluation of bacteriocinlike inhibitory substances produced by lactic acid bacteria isolated during traditional sicilian cheese making

Bacteriocins are antimicrobial proteins produced by bacteria that inhibit the growth of other bacteria with a bactericidal or bacteriostatic mode of action. Many lactic acid bacteria (LAB) produce a high diversity of different bacteriocins. Bacteriocinogenic LAB are generally recognised as safe (GRAS) and useful to control the frequent development of pathogens and spoilage microorganisms. For this reason they are commonly used as starter cultures in food fermentations. In this study, the authors describe the results of a screening on 699 LAB isolated from wooden vat surfaces, raw milk and traditional Sicilian cheeses, for the production of bacteriocin-like inhibitory substances, by comparing two alternative methods. The antagonistic activity of LAB and its proteinaceous nature were evaluated using the spot-on-thelawn and the well-diffusion assay (WDA) and the sensitivity to proteolytic (proteinase K, protease B and trypsin), amylolytic (a-amylase) and lipolytic (lipase) enzymes. The indicator strains used were: Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella enteritidis. A total of 223 strains (belonging to the species Enterococcus spp., Lactobacillus spp., Pediococcus spp., Streptococcus spp., Leuconostoc spp. and Lactococcus lactis) were found to inhibit the growth of Listeria monocytogenes by using the spot-on-the-lawn method; only 37 of these were confirmed by using the WDA. The direct addition of bacteriocin-producing cultures into dairy products can be a more practical and economic option for the improvement of the safety and quality of the final product

Dietary studies in birds: testing a non-invasive method using digital photography in seabirds

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Dietary studies give vital insights into foraging behaviour, with implications for understanding changing environmental conditions and the anthropogenic impacts on natural resources. Traditional diet sampling methods may be invasive or subject to biases, so developing non-invasive and unbiased methods applicable to a diversity of species is essential. We used digital photography to investigate the diet fed to chicks of a prey-carrying seabird and compared our approach (photo-sampling) to a traditional method (regurgitations) for the greater crested tern Thalasseus bergii. Over three breeding seasons, we identified >24 000 prey items of at least 48 different species, more than doubling the known diversity of prey taken by this population of terns. We present a method to estimate the length of the main prey species (anchovy Engraulis encrasicolus) from photographs, with an accuracy <1 mm and precision ~ 0·5 mm. Compared to regurgitations at two colonies, photo-sampling produced similar estimates of prey composition and size, at a faster species accumulation rate. The prey compositions collected by two researchers photo-sampling concurrently were also similar. Photo-sampling offers a non-invasive tool to accurately and efficiently investigate the diet composition and prey size of prey-carrying birds. It reduces biases associated with observer-based studies and is simple to use. This methodology provides a novel tool to aid conservation and management decision-making in the light of the growing need to assess environmental and anthropogenic change in natural ecosystems.Department of Science and Technology, South Afric