Ricotta fresca is a whey cheese susceptible of secondary contamination, mainly from Pseudomonas spp. The extension of the shelf life of refrigerated ricotta fresca could be obtained using protective ...cultures inhibiting the growth of this spoilage microorganism. A commercial biopreservative, Lyofast CNBAL, comprising Carnobacterium spp was tested against Pseudomonas spp. The surface of ricotta fresca samples were inoculated either with Pseudomonas spp or Pseudomonas and Carnobacterium spp. Samples were MAP packed, stored at 4 °C and analyzed the day of the inoculum and 7, 14 and 21 days after the contamination. Microbiological analyses included total bacterial count, mesophilic lactic acid bacteria, Enterobacteriaceae, Pseudomonas spp, Listeria monocytogenes, moulds and yeasts. Pseudomonas mean initial contamination level was comparable in blank and artificially inoculated samples, respectively with values of 2.15 ± 0.21 and 2.34 ± 0.26 log cfu g−1. Carnobacterium spp. significantly reduced the growth of Pseudomonas spp respectively of 1.28 log and 0.83 log after 14 and 21 days of refrigerated storage. Intrinsic properties and physico-chemical composition were also investigated. Limited variation of pH was observed in samples inoculated with the protective cultures, indicating low acidification properties of Carnobacterium spp. Instead, no significant differences were observed for aW, moisture, fat and proteins during storage and between inoculated and control samples.
•Pseudomonas spp is the main spoilage microorganism in refrigerated ricotta fresca.•A microbiological challenge test was conducted on MAP ricotta fresca samples.•Carnobacterium spp commercial protective culture was tested against Pseudomonas spp.•Inoculation of Carnobacterium spp protective culture reduced Pseudomonas spp growth.
Selective pressure in the aquatic environment of intensive fish farms leads to acquired antibiotic resistance. This study used the broth microdilution method to measure minimum inhibitory ...concentrations (MICs) of 15 antibiotics against 104 Aeromonas spp. strains randomly selected among bacteria isolated from Sparus aurata reared in six Italian mariculture farms. The antimicrobial agents chosen were representative of those primarily used in aquaculture and human therapy and included oxolinic acid (OXA), ampicillin (AM), amoxicillin (AMX), cephalothin (CF), cloramphenicol (CL), erythromycin (E), florfenicol (FF), flumequine (FM), gentamicin (GM), kanamycin (K), oxytetracycline (OT), streptomycin (S), sulfadiazine (SZ), tetracycline (TE) and trimethoprim (TMP). The most prevalent species selected from positive samples was Aeromonas media (15 strains). The bacterial strains showed high resistance to SZ, AMX, AM, E, CF, S and TMP antibiotics. Conversely, TE and CL showed MIC90 values lower than breakpoints for susceptibility and many isolates were susceptible to OXA, GM, FF, FM, K and OT antibiotics. Almost all Aeromonas spp. strains showed multiple antibiotic resistance. Epidemiological cut-off values (ECVs) for Aeromonas spp. were based on the MIC distributions obtained. The results showed a high frequency of Aeromonas spp. contamination in Sparus aurata reared on the Italian coast and an elevated biodiversity in isolated bacterial strains. Aeromonas isolates comprise potentially pathogenic species for humans, often resistant to several antibiotics and able to transfer the genes responsible for antibiotic resistance to microorganisms pathogenic for humans throughout the food chain. The few ECV studies available on many antibiotics against Aeromonas spp. strains isolated from the aquaculture environment highlight the need for further research in this area, while regular monitoring programmes should be stepped up to check for antibiotic resistance.
•Aeromonas spp. strains isolated from Sparus aurata were tested against 15 antibiotics.•Almost all strains showed multiple antibiotic resistance.•Epidemiological cut-off values (ECV) revealed a high prevalence of wild-type strains.
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•E. coli concentration was assessed in bivalve molluscs farmed in Sardinia.•Effect of rainfall on the classification of bivalve production areas was evaluated.•In the investigated ...sites, rain in the previous seven days had the greater association with E. coli.•The risk of E. coli above limit increased according to cumulative amount of rain.•Rainfall should be considered before harvesting to reduce the risk of contamination.
Rainfall is generally accepted as one of the most important factors associated with an increased level of E. coli in bivalve molluscs. Performing microbiological risk assessment is relevant to official control authorities to determine the sanitary status of harvesting areas and, therefore, develop monitoring strategies and identify management practices that could be used to improve the quality and safety of the final product. The present study aimed to investigate the impact of rainfall on the content of E. coli in bivalve molluscs farmed in Sardinia (Italy). Enumeration of E. coli was performed according to the Most Probable Number (MPN) method (ISO 16649-3) on 1,920 bivalve samples collected from 7 regional counties between 2018 and 2020. Bivalve molluscs samples included 955 mussels (Mytilus galloprovincialis), 500 oysters (Crassostrea gigas), 325 clams (Ruditapes decussatus), 94 warty venus (Venus verrucosa), and 46 lagoon cockles (Cerastoderma glaucum). Rainfall data were obtained by the Department of Meteorology of the ARPA Sardegna. For each sampling site, GPS coordinates were used to identify gauge stations within catchment areas. Cumulative rain (mm) was recorded 1, 3, 5, 7, and 15 days before sampling, among which the 7-day cumulative rain was the strongest predictor of E. coli counts. Several thresholds of 7-day cumulative rain (from <10 mm up to >300 mm) before sampling were used to estimate the chances of a non-compliant sample (E. coli levels above the limit for sanitary class A; 230 MPN/100 g). The 7-day cumulative rain was positively associated with the chances of non-compliance. When the 7-day cumulative rain before sampling was >300 mm, 80.5 % of the samples were non-compliant, and the odds of a non-compliant sample were 23.6 times higher, as compared to samples harvested when the 7-day cumulative rainfall was <10 mm. Precipitation data could be a useful tool for interpreting anomalous results from official control authorities and reduce the costs that originate from closure of production areas.
Ricotta fresca cheese is susceptible to secondary contamination and is able to support the growth of pathogens or spoilage psychotrophic bacteria during storage. The aim of the present study was to ...evaluate which among three commercial biopreservatives was suitable to be used to control the growth of spoilage microorganisms in sheep's milk MAP ricotta fresca cheese. 144 Ricotta fresca cheese samples were inoculated either with the bioprotective culture Lyofast FPR 2 (including Enterococcus faecium, Lactobacillus plantarum e Lactobacillus rhamnosus) or Lyofast CNBAL (Carnobacterium spp) or the fermentate MicroGARD 430. Not inoculated control and experimental ricotta were MAP packed (30% CO2 and 70% N2) and stored at 4 °C. Triplicate samples were analyzed after 5 h and 7, 14 and 21 days after inoculation for total bacterial count, mesophilic lactic acid bacteria, Enterobacteriaceae, Pseudomonas spp, Listeria monocytogenes, moulds and yeasts. Among the tested biopreservatives only Carnobacterium spp was able to control Pseudomonas spp and Enterobacteriaceae. The maximum reduction in the concentration of Pseudomonas spp and Enterobacteriaceae was respectively 1.93 and 2.66 log10 cfu/g, observed 14 days after production. Therefore, Carnobacterium spp was selected as the culture of choice to conduct a challenge study against Pseudomonas spp.
•Ricotta fresca support psychotrophic microorganism growth during refrigerated storage.•3 Commercial biopreservatives were tested against spoilage bacteria in ricotta fresca.•Cultures Lyofast FPR 2, Lyofast CNBAL and the fermentate FERM 430D were tested.•Inoculation of Carnobacterium spp protective culture reduced Pseudomonas spp growth.
The genus Arcobacter include species considered as human foodborne enteropathogens. In recent years, Arcobacter spp. have been frequently isolated from various food of animal origin such as meat, ...fish and dairy products. However, there is still little information on the occurrence of Arcobacter spp. in the dairy sheep chain. The present study was aimed to assess the prevalence of Arcobacter spp. in the processing environment of 10 industrial and 10 artisanal cheese making plants using sheep milk. A total of 250 samples were collected including food contact and non-food contact surfaces, cheeses, water and wastewater samples. Species identification of isolates was conducted by multiplex PCR and PCR-RFLP. Arcobacter spp. were isolated in 11 out of 20 cheese-making plants (55.0%) with an overall prevalence of 19.2%. Of Arcobacter positive samples 32 (66.6%) were detected from environmental surfaces, 11 (22.9%) from food samples and 5 from wastewater (10.4%). Arcobacter was never recovered from water samples. No differences were observed between industrial and artisanal cheese-making plants. Of 48 isolated strains, 39 (81.3%) were A. butzleri, 5 (10.4%) A. cryaerophilus and 4 (8.3%) A. skirrowii. This is the first investigation reporting the detection of A. cryaerophilus and A. skirrowii from both environmental surfaces and cheeses in dairy plants using sheep milk. Contamination was observed respectively in 6 ricotta (20.0%) and in 3 fresh cheeses (23.1%). The present study indicates the potential risk for human health associated to cheese obtained with pasteurized milk due to cross contamination originating from the processing environment. To minimize the risk of transmission of Arcobacter spp. to consumers through the ingestion of contaminated foods it is essential the implementation of environmental monitoring programs to collect samples from food processing surfaces and to detect the presence of this potential human pathogen.
•Prevalence of Arcobacter spp. in the dairy sheep sector was investigated.•Overall prevalence of Arcobacter spp. was 19.2%.•Arcobacter spp. was isolated from processing environment, wastewater and cheeses.•It is the first report of A. cryaerophilus and A. skirrowii in sheep dairy plants.
Growth potential of Listeria monocytogenes was assessed in Ricotta salata, a traditional sheep’s whey cheese. 36 Ricotta salata wheels were inoculated with a mixture of three L. monocytogenes strains ...obtaining an inoculum level of approximately 102 cfu g−1. Samples were analyzed for the detection and enumeration of L. monocytogenes after 6 h, and after 2, 4 and 6 months. Growth potential (log10 cfu g−1) was 4.87, 6.90 and 6.20 at 2, 4 and 6 months, respectively. The greater relative rate of increase in L. monocytogenes levels was obtained in the first 2 months after inoculation. Ricotta salata supports the growth of L. monocytogenes to levels that may represent a serious risk to public health even during storage at refrigeration temperatures. Further research is needed to assess the effectiveness of post-lethality treatments to reduce the initial level of contamination or of competitive microflora to limit the extent of pathogen growth.
As a control measure for Listeria monocytogenes contamination a post-lethality heat treatment was applied in vacuum packaged Ricotta salata, a traditional whey cheese obtained from sheep’s milk. In ...Ricotta salata L. monocytogenes usually occurs as post-process contamination and its concentration can increase during storage at refrigeration temperature. Ricotta salata wheels were challenged spraying the rind with a L. monocytogenes suspension, obtaining a contamination level of ca. 106 cfu g−1. In order to take into account strains differences in growth, the inoculum contained a mixture of the reference strain NCTC 10887 (serovar 1/2b) and two wild type (serovar 1/2a) strains. 87 artificially contaminated Ricotta wheels were randomly selected and subjected to water bath heat treatment at 85 °C for 90 min, while 21 served as negative controls. Samples were stored at refrigeration temperatures until analysis. L. monocytogenes, background microflora and physico-chemical properties were assessed 6 h, 2, 4, 6 and 12 months after the artificial contamination. Pulsed filed gel electrophoresis was conducted to distinguish between the inoculated and recovered strains. L. monocytogenes cells were below the limit for the enumeration method in samples submitted to the lethal treatment. Heat treatment was effective to achieve a 6 log10 reduction of L. monocytogenes cells.
► We assessed the effectiveness of heat treatment on L. monocytogenes survival. ► Ricotta salata were contaminated with a mixture of 3 L. monocytogenes strains. ► A reduction of 6 log10 cfu g−1 in L. monocytogenes count was obtained.
Adiponectin is an insulin-sensitizing, anti-inflammatory adipokine with anti-atherogenic actions in the general population. In dialysis patients it is unclear whether adiponectin conserves its ...protective value or is, on the contrary, associated to worse prognosis. We assessed the predictive value of adiponectin for atherosclerosis related cardiovascular events in type 2 diabetic dialysis patients.
Prevalent diabetic dialysis patients from three dialysis units (n=77) were enrolled in a 3years' prospective observational study. Serum adiponectin, clinical and laboratory parameters were determined at baseline; new occurrence of atherosclerosis related events (coronary events, atherosclerosis obliterans, and stroke) was recorded.
Baseline adiponectin was 17.25(9.53–31.97) μg/mL and significantly correlated to HDL cholesterol (r=0.29, p=0.01), triglycerides (r=−0.40, p=0.0004), ferritin (r=−0.29, p=0.02), transferrin (r=−0.28, p=0.02), and uric acid (r=−0.24, p=0.04). In multivariate analysis association to triglycerides (p=0.001), HDL cholesterol (p=0.01) and ferritin (p=0.04) remained significant. 36 new fatal and non-fatal new cardiovascular events occurred, 29 patient died. Cox proportional regression analysis showed that adiponectin below or above a ROC-derived cut-off of 27.33μg/mL significantly influenced event-free survival: hazard ratio (HR) 2.48, 95% confidence interval (CI) (1.09–5.66), p=0.031 along with fasting glucose HR 1.01, 95%CI(1.00–1.02), p=0.01 and history of cardiovascular events at inclusion HR 3.16, 95%CI(1.36–7.32), p=0.007. In multivariate analysis baseline adiponectin HR 5.02, 95%CI(0.98–25.06), p=0.05 and glycemia HR 1.01, 95%CI(1.00–1.02), p=0.01 influenced event-free survival. Adiponectin also predicted cardiovascular events in patients without cardiovascular disease at inclusion but was not associated to overall mortality.
In diabetes dialysis patients low adiponectin favors occurrence of atherosclerosis related cardiovascular events.
•We address controversy regarding the role of adiponectin in chronic kidney disease.•Our work is one of the few (second) studies in diabetes dialysis patients.•Adiponectin conserves its protective effect against atherosclerosis events.•We discuss confounding factors for the protective role of adiponectin in chronic kidney disease.
Mastitis of small dairy ruminants is usually subclinical, and coagulase negative staphylococci have been reported as the most commonly isolated pathogens. Intramammary antimicrobial therapy ...administered at dry off is one of the most effective tools for mastitis control in dairy cows. The primary objective of this study was to determine the effect of intramammary antimicrobial dry treatment given to milking ewes on prevalence of intramammary infection and somatic cell count in the subsequent lactation. The secondary objective was to assess the impact of premilking teat sanitation on somatic cell count. Milking ewes (
n
=
245) were randomly allocated to receive either an intramammary infusion of 300
mg cephapirin benzathine (dry treated) or no dry treatment (not treated). After lambing, before the first mechanical milking, half udder milk samples were aseptically collected for bacteriology. Additional milk samples were collected at day 14–21 (follow up samples). Coagulase negative staphylococci were the most prevalent isolates and were recovered from 45 to 48% of culture positive milk samples. Milk samples obtained from ewes with 3 or more monthly somatic cell counts ≥400,000
cells/mL in the previous lactation were 5.6–7.5 times more likely to be microbiologically positive for mastitis pathogens as compared to milk samples obtained from ewes with SCC below that threshold. Dry treatment had a significant effect on somatic cell count in the subsequent lactation but did not influence the probability of intramammary infection at lambing or follow up sampling. Premilking teat sanitation did not show significant effect on somatic cell count.
► PCDD/Fs and PCBs were determined in sheep milk samples. ► Milk samples were collected from an industrialized area of Sardinia, Italy. ► Overall milk contamination level was below the limit values ...for human consumption. ► Samples the nearest to pollution sources had concentrations above the action level. ► On the whole the results revealed a situation of moderate contamination.
Concentrations of 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs) and 22 polychlorinated biphenyls (PCBs), including 12 dioxin like-PCBs (non- and mono-ortho PCBs) were measured in 80 sheep milk samples from farms located in an industrialized area of Sardinia, Italy. PCDDs and PCDFs mean concentrations were 2.45 and 3.69pgg−1 fat basis, respectively. The mean dl-PCB concentration was 2.01ngg−1 fat basis, while cumulative ndl-PCB levels ranged from 1.02 to 20.42, with a mean of 4.92ngg−1 fat. The results expressed in pg WHO-TEQ/g fat showed that contamination level of milk was below the limit values for human consumption established by EC legislation. In the same way, all the investigated milk exhibited PCDD/Fs concentrations below EU action levels, while dl-PCBs concentrations exceeded the action level of 2.0pg WHO-TEQ/g fat. These findings point to the need to continue to conduct general monitoring programmes, including also milk samples from areas not close to the contaminant-emitting industries, in order to better evaluate the impact of industrial activities on surrounding environment.
