Behaviour of Escherichia coli O157:H7 during the manufacture and ripening of an Italian traditional raw goat milk cheese

Formagelle di capra is a raw goat cheese produced from whole chilled goat milk; traditional technology involving unpasteurised milk and indigenous lactic starter cultures is employed for its production in Italy. The purpose of this study was to assess the behavior of Escherichia coli O157:H7 during the manufacturing and ripening of this raw goat milk cheese. Raw milk was experimentally inoculated with E. coli O157:H7 in a laboratory scale plant and the count was monitored during production and 30 days of ripening required for this cheese. Results showed that E. coli O157:H7 count increased to more than 1.5 Log cfu g-1 during cheese production and remained constant until the end of ripening. The evidence that E. coli O157:H7 is able to survive during the manufacturing and ripening process suggests that the 30-day ripening period alone is insufficient to eliminate levels of viable E. coli O157:H7 in Formaggelle di capra cheese and that the presence of low numbers of E. coli O157:H7 in milk destined for the production of raw goat milk cheeses could represent a potential source of infection for humans and a threat for consumer

Behavior of listeria innocua during the manufacturing and pit-ripening of formaggio di fossa di sogliano pdo cheese

Formaggio di Fossa di Sogliano is a traditional Italian Protected Designation of Origin (PDO) cheese ripened for a minimum of 5 months, with the feature of a ripening of at least 80 to at most 100 days in pits, digged into tuffaceous rocks according to medieval tradition of Italy. In this study, a challenge test using Listeria innocua as a surrogate of Listeria monocytogenes was performed, with the aim of increasing knowledge concerning the impact of the Fossa cheese process, and especially of the traditional ripening process of this PDO, on the behaviourof L. monocytogenes. Pasteurized milk was experimentally inoculated with 4.5 log CFU/mL cocktail by three L. innocua strains, and L. innocua and Mesophilic Lactic Acid Bacteria (LAB) counts as well as the evolution of temperatures, pH and aw values were monitored throughout the manufacturing and ripening processes. Throughout the ripening in maturation room a constant temperature of 8\ub0C was observed reaching a temperature between 10 and 15.5\ub0C during ripening into pit. In the final products data for LAB concentration, pH and aw values were roughly in accordance with literature, even if some differences were, probably due to variability of artisanal cheese productions. The numbers of L. innocua showed a slight decrease but remained stable until the end of ripening in maturation room, whereas a significant reduction of the microorganism was observed in the final product, at the end of the ripening into the pit. The findings give scientific evidence that the process of this PDO prevented the L. innocua growth, allowing us to speculate a similar behaviour of L. monocytogenes. Based on this study, the recommendation to extend as much as possible the ripening into pit (from 80 to 100 days) was provided to food business operators as a risk mitigation strategy to be implemented

Size of HIV-1 reservoir is associated with telomere shortening and immunosenescence in early-treated European children with perinatally acquired HIV-1

INTRODUCTION: Persistence of HIV-1, causing chronic immune activation, is a key determinant of premature senescence. Early antiretroviral therapy (ART) has been associated with a reduced HIV-1 reservoir in children with perinatally acquired HIV-1 (PHIV), but its impact on the senescence process is an open question. We investigated the association between HIV-1 reservoir and biological and immune ageing profile in PHIV enrolled in the multicentre cross-sectional study CARMA (Child and Adolescent Reservoir Measurements on early suppressive ART) conducted within the EPIICAL (Early treated Perinatally HIV Infected individuals: Improving Children's Actual Life) consortium. METHODS: Between September 2017 and June 2018, CARMA enrolled 40 PHIV who started ART before 2 years of age and had undetectable viremia for at least 5 years before sampling date. Samples from 37 children with a median age of 13.8 years were available for this study. HIV-1 DNA copies on CD4 cells, relative telomere length (marker of cellular senescence) and levels of T-cell receptor rearrangement excision circle (TREC, marker of thymic output) on CD4 and CD8 cells were quantified by qPCR. Immunological profile was assessed by flow cytometry. Associations between molecular and phenotypic markers, HIV-1 reservoir and age at ART initiation were explored using a multivariable Poisson regression. RESULTS: Higher HIV-1 reservoir was associated (p<0.001) with telomere shortening (incidence rate ratio [IRR] = 0.15 [0.13-0.17]), immunosenescence (CD28- CD57+ , IRR = 1.23 [1.21-1.26]) and immunoactivation (CD38+ HLADR+ , IRR = 7.29 [6.58-8.09]) of CD4 cells. Late ART initiation (after 6 months of age) correlated with higher HIV-1 reservoir levels (552 [303-1001] vs. 89 [56-365] copies/106 CD4 cells, p = 0.003) and percentage of CD4 senescent cells (2.89 [1.95-6.31] vs. 1.02 [0.45-2.69, p = 0.047). TREC levels in CD8 cells were inversely associated with HIV-1 reservoir (IRR = 0.77 [0.76-0.79]) and were significantly lower in late treated PHIV (1128 [486-1671] vs. 2278 [1425-3314], p = 0.042). CONCLUSIONS: Later ART initiation is associated with higher HIV-1 reservoir size, which correlates with increased telomere shortening and senescence of CD4 cells. Timing of ART initiation in infancy has long-term consequences on the immune and biological ageing profile of children with perinatally acquired HIV-1

The presence, genetic diversity and behaviour of Listeria monocytogenes in blue-veined cheese rinds during the shelf life

Blue-veined cheeses may allow Listeria monocytogenes survival and multiplication due to the biochemical characteristics of the cheese and the growth characteristics of the pathogen. Because of the availability of a considerable number of samples, we wanted this study to take a large view of the microbiota and of the incidence and genetic diversity of L. monocytogenes in blue-veined cheese rinds. Moreover, we wanted to determine if the pathogen present on the rinds at the end of ripening represented a risk to the consumer if the cheese should exceed the domestic storage limit imposed by Commission Regulation (EC) No 2073/ 2005 for food safety criteria. The rind microflora showed a high level of heterogeneity, and the incidence of L. monocytogenes (never found in the paste samples) was 55%, with an increased presence and concentration associated with a longer ripening time. Amplified Fragment Length Polymorphism (AFLP) was used to characterise L. monocytogenes isolated from blue-veined cheese rinds and highlighted the heterogeneity among the strains, demonstrating its suitability for studying the biodiversity of the pathogen in this environment. L. monocytogenes was able to grow during the shelf life of the cheese and was influenced by the refrigeration temperatures and the physicochemical characteristics of the cheese

The presence, genetic diversity and behaviour of Listeria monocytogenes in blue-veined cheese rinds during the shelf life

Blue-veined cheeses may allow Listeria monocytogenes survival and multiplication due to the biochemical characteristics of the cheese and the growth characteristics of the pathogen. Because of the availability of a considerable number of samples, we wanted this study to take a large view of the microbiota and of the incidence and genetic diversity of L.monocytogenes in blue-veined cheese rinds. Moreover, we wanted to determine if the pathogen present on the rinds at the end of ripening represented a risk to the consumer if the cheese should exceed the domestic storage limit imposed by Commission Regulation (EC) No 2073/2005 for food safety criteria.The rind microflora showed a high level of heterogeneity, and the incidence of L.monocytogenes (never found in the paste samples) was 55%, with an increased presence and concentration associated with a longer ripening time. Amplified Fragment Length Polymorphism (AFLP) was used to characterise L.monocytogenes isolated from blue-veined cheese rinds and highlighted the heterogeneity among the strains, demonstrating its suitability for studying the biodiversity of the pathogen in this environment. L.monocytogenes was able to grow during the shelf life of the cheese and was influenced by the refrigeration temperatures and the physicochemical characteristics of the cheese. © 2013 Elsevier Ltd