Effect of negative air ionization technology on microbial reduction of food-related microorganisms

Negative air ions (NAI) have been shown to have bactericidal effects on various microbial species. Different concentrations of NAI and ozone (106-7x106 NAI cm-3 s−1, 2.20 mg h-1 of ozone or 8 × 106-2x107 NAI cm−3 s−1, 0.02 mg h−1 of ozone, respectively) were studied to determine whether the effect of these treatments on six food-related microorganisms was due to NAI or also to the ozone that forms. Bacillus subtilis, Escherichia coli, and Listeria monocytogenes showed a significantly microbial reduction after the treatments of NAI with a low concentration of ozone, while Pseudomonas fluorescens, Penicillium roqueforti, and Saccharomyces cerevisiae were affected mainly by NAI and higher ozone concentration. It should be noticed that the reduction of the pathogen L. monocytogenes has been 2.17 Log after 72 h treatment to NAI and low ozone concentration. The results proved that ions (NAI) contribute to microbial killing. However, the sensitivity of microbial species is different and depends on individual parameters of the different microorganisms. NAI technology with low ozone production can be rapid, green, and low-cost and it can represent an alternative to the use of chemicals for the sanitation of air and surfaces in the food sector in order to reduce microbial contamination

Application of pre-adaptation strategies to improve the growth of probiotic lactobacilli under food-relevant stressful conditions

While formulating a probiotic food, it is mandatory to make sure that the viability of probiotics is adequate at the point of consumption, which can be strongly compromised by stressful conditions due to low pH and high osmolarity. In this study, three probiotic lactobacilli were subjected to different pre-adaptation conditions, and the turbidimetric growth kinetics in challenging conditions (pH 4.0–6.5, NaCl 1–7%, sucrose 0.1–0.7 M) were evaluated. Different effects were observed for Lactobacillus acidophilus, Lacticaseibacillus casei, and Lactiplantibacillus plantarum. Indeed, pre-exposition to sub-optimal conditions in terms of pH and % NaCl significantly improved the ability of L. acidophilus and L. casei to overcome the osmotic stress due to salt or sucrose, and similar effects were observed for acidic stress. L. plantarum showed to be more tolerant to the challenging conditions applied in this study. Anyway, the pre-adaptation at conditions SUB_1 (pH 4.5 and NaCl 4%) and SUB_2 (pH 5 and NaCl 2%) speeded-up its growth kinetics by reducing the length of the lag phase under sucrose stress and enhancing the maximum growth rate at the highest pH tested. Moreover, an improvement in biomass amount was observed under sucrose stress. The whole data evidenced that the application of the appropriate pre-adaptation condition could contribute to making probiotics more robust towards challenging conditions due to food matrix, processing, and storage as well as gastrointestinal transit. Further studies will be necessary to gain insight into the proteomics and metabolomics responsible for increased tolerance to stressful conditions

Inactivation of Foodborne Bacteria Biofilms by Aqueous and Gaseous Ozone

In this study, the efficacy of treatments with ozone in water and gaseous ozone against attached cells and microbial biofilms of three foodborne species, Pseudomonas fluorescens, Staphylococcus aureus, and Listeria monocytogenes, was investigated. Biofilms formed on AISI 304 stainless steel coupons from a mixture of three strains (one reference and two wild strains) of each microbial species were subjected to three types of treatment for increasing times: (i) ozonized water (0.5 ppm) by immersion in static condition, (ii) ozonized water under flow conditions, and (iii) gaseous ozone at different concentrations (0.1\u201320 ppm). The Excel add-in GinaFit tool allowed to estimate the survival curves of attached cells and microbial biofilms, highlighting that, regardless of the treatment, the antimicrobial effect occurred in the first minutes of treatment, while by increasing contact times probably the residual biofilm population acquired greater resistance to ozonation. Treatment with aqueous ozone under static conditions resulted in an estimated viability reduction of 1.61\u20132.14 Log CFU/cm2 after 20 min, while reduction values were higher (3.26\u20135.23 Log CFU/cm2 ) for biofilms treated in dynamic conditions. S. aureus was the most sensitive species to aqueous ozone under dynamic conditions. With regard to the use of gaseous ozone, at low concentrations (up to 0.2 ppm), estimated inactivations of 2.01\u20132.46 Log CFU/cm2 were obtained after 60 min, while at the highest concentrations a complete inactivation (<10 CFU/cm2 ) of the biofilms of L. monocytogenes and the reduction of 5.51 and 4.72 Log CFU/cm2 of P. fluorescens and S. aureus respectively after 60 and 20 min were achieved. Considering the results, ozone in water form might be used in daily sanitation protocols at the end of the day or during process downtime, while gaseous ozone might be used for the treatment of confined spaces for longer times (e.g., overnight) and in the absence of personnel, to allow an eco-friendly control of microbial biofilms and consequently reduce the risk of cross-contamination in the food industry

Technical note: Rapid method for determination of amino acids in milk.

A rapid method for measurement of amino acids in milk was developed and validated. The method included a first step of milk protein hydrolysis, followed by the derivatization and separation of amino acids by HPLC. Six combinations of hydrolysis agent and temperature-time conditions were compared with a reference method; derivatization procedures as well as HPLC separation were improved. Hydrolysis of milk samples with 6 N HCl at 160 degrees C for 60 min resulted in no significantly differences compared with the reference method but allowed the analysis of a greater number of milk samples in a short time. In addition, this method was characterized by high precision, low repeatability uncertainty, and high accuracy for all amino acids evaluated; the recovery mean value of the single amino acids was 98.38%. The proposed method is, therefore, accurate, simple, rapid, and suitable for large numbers of milk samples

Metagenomic profiles of different types of Italian high-moisture Mozzarella cheese

The microbiota of different types of Italian high-moisture Mozzarella cheese produced using cow or buffalo milk, acidified with natural or selected cultures, and sampled at the dairy or at the mass market, was evaluated using a Next Generation Sequencing approach, in order to identify possible drivers of the bacterial diversity. Cow Mozzarella and buffalo Mozzarella acidified with commercial cultures were dominated by Streptococcus thermophilus, while buffalo samples acidified with natural whey cultures showed similar prevalence of L. delbrueckii subsp. bulgaricus, L. helveticus and S. thermophilus. Moreover, several species of non-starter lactic acid bacteria were frequently detected. The diversity in cow Mozzarella microbiota was much higher than that of water buffalo samples. Cluster analysis clearly separated cow's cheeses from buffalo's ones, the former having a higher prevalence of psychrophilic taxa, and the latter of Lactobacillus and Streptococcus. A higher prevalence of psychrophilic species and potential spoilers was observed in samples collected at the mass retail, suggesting that longer exposures to cooling temperatures and longer production-to-consumption times could significantly affect microbiota diversity. Our results could help in detecting some kind of thermal abuse during the production or storage of mozzarella cheese

Diversity within Italian Cheesemaking Brine-Associated Bacterial Communities Evidenced by Massive Parallel 16S rRNA Gene Tag Sequencing

This study explored the bacterial diversity of brines used for cheesemaking in Italy, as well as their physicochemical characteristics. In this context, 19 brines used to salt soft, semi-hard, and hard Italian cheeses were collected in 14 commercial cheese plants and analyzed using a culture-independent amplicon sequencing approach in order to describe their bacterial microbiota. Large NaCl concentration variations were observed among the selected brines, with hard cheese brines exhibiting the highest values. Acidity values showed a great variability too, probably in relation to the brine use prior to sampling. Despite their high salt content, brine microbial loads ranged from 2.11 to 6.51 log CFU/mL for the total mesophilic count. Microbial community profiling assessed by 16S rRNA gene sequencing showed that these ecosystems were dominated by Firmicutes and Proteobacteria, followed by Actinobacteria and Bacteroidetes. Cheese type and brine salinity seem to be the main parameters accountable for brine microbial diversity. On the contrary, brine pH, acidity and protein concentration, correlated to cheese brine age, did not have any selective effect on the microbiota composition. Nine major genera were present in all analyzed brines, indicating that they might compose the core microbiome of cheese brines. Staphylococcus aureus was occasionally detected in brines using selective culture media. Interestingly, bacterial genera associated with a functional and technological use were frequently detected. Indeed Bifidobacteriaceae, which might be valuable probiotic candidates, and specific microbial genera such as Tetragenococcus, Corynebacterium and non-pathogenic Staphylococcus, which can contribute to sensorial properties of ripened cheeses, were widespread within brines. \ua9 2017 Marino, Innocente, Maifreni, Mounier, Cobo-D\uedaz, Coton, Carraro and Cardazzo

In the Shade of Dorado Group Giants: Tracing the Eventful Life of Member Galaxies in Optical and Far UV

Groups are key to understand the galaxy evolution: they contain most of the galaxies in Universe at present day, most of the stellar mass and have their own way to transform galaxies from active to passive. Our aim is understanding the mechanisms driving the co-evolution of galaxies in nearby groups. Rich of early-type galaxies showing shells and FUV bright rings, Dorado is a nearby (16.9 Mpc Firth et al. 2006, MNRAS, 372, 1856) loose (about 10 deg2 , Carrasco et al 2001, AJ, 121, 148) association still non-virialized, likely a way station towards rich, virialized groups. We are mapping the group via deep VST g, r SDSS filters and (hopefully) Astrosat-UVIT; Far and Near UV imaging from GALEX and Swift-UVOT are also available. Our targets include the giant earlytype galaxies (ETGs) marking the group backbone as well as their intermediate companions and dwarfs whose luminosity function is still largely incomplete. The optical and Far UV analysis is shedding light on the Dorado evolving phase, showing residual star formation in evolved giant ETGs

True Cost Accounting of a healthy and sustainable diet in Italy

It is widely upheld that global food systems are unsustainable. Sustainable diets are gaining prominence as key components to entangle global food system challenges, as well as to transition towards the pathway of the 2030 Agenda and the Sustainable Development Goals (SDGs). Hence, sustainable and healthy diets are at the core of much research with the aim to bring together nutritional adequacy, cultural acceptability, environmental sustainability, economic affordability, and shape future consumption patterns. This article contributes to advancing knowledge on sustainable diets by proposing a True Cost Accounting method to assess the cost and impact of the adoption of a more sustainable and healthier diet, using Italy as an illustration. The research analyses the complexity of a diet from an environmental, health, and socioeconomic point of view and defines a new assessment framework that can be replicated and adapted to other contexts. Results show that in Italy, the adoption of a sustainable and healthy diet has a 47% lower carbon footprint and 25% lower water footprint than the current diet, while impacting 13% less on the average income and food monthly expenditure. Also, the desirable diet has a 21% lower impact on the sanitary costs related to cardiovascular disease. This study corroborates that the consumption of the desirable diet would provide a total cost saving of 741 EUR per year per capita, if we consider its impact on the environment, health, and socio-economic costs