Category Archives: Research

Research – Application of Ultrasound Treatments in the Processing and Production of High-Quality and Safe-to-Drink Kiwi Juice

MDPI

Abstract

This study explores the potential of thermosonication as an alternative to traditional heat treatments, such as pasteurization, in the processing of fruit juices. Conventional methods often lead to undesirable quality changes in fruit juices, whereas thermosonication offers promising results regarding microbial inactivation and quality preservation. This work focused on the inactivation kinetics of Listeria innocua 2030c, a surrogate for pathogenic L. monocytogenes, in kiwifruit juice using thermosonication at 45 °C, 50 °C, and 55 °C. These treatments were compared with equivalent heat treatments. Quality attributes of the juice were also evaluated to assess process efficiency. Survival data of L. innocua were fitted with the Weibull model, estimating first decimal reduction times (δ) and shape parameters (n). The results reveal temperature and process dependencies on δ, while n remains mostly temperature and treatment independent. Thermosonication outperforms heat treatment, achieving higher L. innocua reductions while retaining quality attributes like pH, soluble solid content, and total phenolics and chlorophylls. Thermosonication at 55 °C stands out, providing a 6.2-log-cycle reduction in just 3 min with superior quality retention. These findings highlight the synergistic effect of temperature and ultrasound, making mild heat processes feasible while enhancing product quality. Thermosonication, particularly at 55 °C, emerges as an effective alternative to traditional thermal treatments for fruit juices, offering improved microbial safety without compromising product quality.

France – Norovirus suspected in large Airbus outbreak

Food Safety News

Norovirus has been determined to be the suspected cause of a large outbreak at Airbus in France in late 2023, according to public health officials.

The Loire-Atlantique regional health agency (ARS) believes norovirus was behind almost 700 people falling sick at the Airbus Atlantic Christmas lunch in mid-December. Findings are based on the clinical symptoms in patients and the time it took for them to appear.

Sick people reported suffering from nausea, vomiting, and diarrhea after the event in Montoir at the company’s restaurant. Testing of food leftovers was negative for norovirus. No detail was given on whether patients or food handlers had been tested.

The varied menu is said to have included a cheese plate, a starter with scallops, a foie gras terrine, beef in sauce, and a lobster dish.

Research – Microbial diversity and prediction function profiling of microbial communities in rose jam

Wiley Online

Abstract

The microbial diversity of rose jam was analyzed by high-throughput sequencing, along with functional prediction of the bacterial community. The results indicate that PseudomonasPantoea, and Burkholderia emerged were the top three dominant bacterial groups. Proteobacteria was particularly abundant in R4 (99.1%) and R6 (96.12%).

Abstract

The microbial diversity of rose jam was analyzed by high-throughput sequencing, along with functional prediction of the bacterial community. The results indicate that PseudomonasPantoea, and Burkholderia emerged were the top three dominant bacterial groups. Proteobacteria was particularly abundant in R4 (99.1%) and R6 (96.12%). Zygosaccharomyces, unclassified fungi, and Botrytis constituted the top three fungal groups. The presence of unclassified OTUs was observed in all samples, particularly in R6 (52.36%), R8 (45.28), and R9 samples (39.57%). Gene prediction using PICRUSt revealed the existence of multiple KEGG functional modules associated with human metabolism in each rose jam sample. The presence of a high abundance of functional genes indicated the microbial community’s diverse wide range of microgenetic resources that can be further explored for research purposes. The microbial community found in rose jam exhibits remarkable diversity and encompasses valuable functional information relevant to human health.

, unclassified fungi, and Botrytis constituted the top three fungal groups. The presence of unclassified OTUs was observed in all samples, particularly in R6 (52.36%), R8 (45.28), and R9 samples (39.57%). Gene prediction using PICRUSt revealed the existence of multiple KEGG functional modules associated with human metabolism in each rose jam sample. The presence of a high abundance of functional genes indicated the microbial community’s diverse wide range of microgenetic resources that can be further explored for research purposes. The microbial community found in rose jam exhibits remarkable diversity and encompasses valuable functional information relevant to human health.

Research – Food-borne pathogen Listeria may hide from sanitizers in biofilms

Phys Org

An estimated 1,600 people in the U.S. contract a serious infection from Listeria bacteria in food each year, and of those individuals, about 260 people die, according to the Centers for Disease Control and Prevention. Penn State researchers may now better understand how the bacteria, called Listeria monocytogenes, survive and persist in fruit-packing plants by evading and surviving sanitizers.

According to their study, which is now available online and will be published in the June issue of the journal Biofilm, biofilms—containing otherwise harmless microorganisms that attach to each other and the food surface—result in a kind of shield that surrounds and protects the Listeria. The findings may result in changes to sanitation protocols in food-processing facilities that promise to diminish contamination of food with Listeria, the researchers said.

UK- Research – How pathogen genomics could help us detect new health threats and improve vaccines.

UKSHA

Pathogen genomics is an important tool in our mission to prepare for and respond to infectious disease threats as well as food safety.

Our new 5-year Pathogen Genomics Strategy will establish a unified programme to enhance and expand our excellence in this field. Using pathogen genomics, we will increase our understanding of infectious disease risks, and enable effective evaluation of interventions to mitigate them.

In this blog post at the above link, we will explore the role of pathogen genomics in UK biosecurity and how we are developing our genomic systems to better protect public health in the UK.

Research – Relationship between Desiccation Tolerance and Biofilm Formation in Shiga Toxin-Producing Escherichia coli

MDPI

Abstract

Shiga toxin-producing Escherichia coli (STEC) is a major concern in the food industry and requires effective control measures to prevent foodborne illnesses. Previous studies have demonstrated increased difficulty in the control of biofilm-forming STEC. Desiccation, achieved through osmotic stress and water removal, has emerged as a potential antimicrobial hurdle. This study focused on 254 genetically diverse E. coli strains collected from cattle, carcass hides, hide-off carcasses, and processing equipment. Of these, 141 (55.51%) were STEC and 113 (44.48%) were generic E. coli. The biofilm-forming capabilities of these isolates were assessed, and their desiccation tolerance was investigated to understand the relationships between growth temperature, relative humidity (RH), and bacterial survival. Only 28% of the STEC isolates had the ability to form biofilms, compared to 60% of the generic E. coli. Stainless steel surfaces were exposed to different combinations of temperature (0 °C or 35 °C) and relative humidity (75% or 100%), and the bacterial attachment and survival rates were measured over 72 h and compared to controls. The results revealed that all the strains exposed to 75% relative humidity (RH) at any temperature had reduced growth (p < 0.001). In contrast, 35 °C and 100% RH supported bacterial proliferation, except for isolates forming the strongest biofilms. The ability of E. coli to form a biofilm did not impact growth reduction at 75% RH. Therefore, desiccation treatment at 75% RH at temperatures of 0 °C or 35 °C holds promise as a novel antimicrobial hurdle for the removal of biofilm-forming E. coli from challenging-to-clean surfaces and equipment within food processing facilities.

Research – Sporadic Shiga Toxin-Producing Escherichia coli-Associated Paediatric Haemolytic Uraemic Syndrome, France, 2012–2021

Sante Publique

Shiga toxin-producing Escherichia coli (STEC) bacteria cause a variety of symptoms, ranging from simple diarrhoea to bloody diarrhoea, and expose patients to an increased risk of serious complications, including haemolytic uraemic syndrome (HUS). HUS due to STEC infection can occur at any age, although it mainly affects children under the age of 5 and the elderly. Over the past decade, several outbreaks of food-borne STEC-HUS have received wide media coverage. For children, this illness remains a significant public health risk in France. Although ruminants (cows, sheep, goats, etc.) are the main reservoir of STEC bacteria, it is difficult to determine the source of contamination in sporadic infections due to the multiple possible modes of contamination (consumption of contaminated food or water, contact with ruminants or their contaminated environment, contact with an infected person, etc.).

Identifying geographic areas where there is a higher risk of sporadic STEC-HUS will help to improve our knowledge of the environmental risk factors associated with the geographic disparities. This was the objective of the study carried out by Santé publique France, in partnership with the National Reference Centre (Centre national de référence, CNR) for E. coli, at the Institut Pasteur, and its associated laboratory at the Robert Debré Teaching Hospital (Centre Hospitalier Universitaire Robert Debré), which was recently published in the journal Emerging Infectious Diseases.

CDC

Research – The Role of Flagellum and Flagellum-Based Motility on Salmonella Enteritidis and Escherichia coli Biofilm Formation

MDPI

Abstract

Flagellum-mediated motility has been suggested to contribute to virulence by allowing bacteria to colonize and spread to new surfaces. In Salmonella enterica and Escherichia coli species, mutants affected by their flagellar motility have shown a reduced ability to form biofilms. While it is known that some species might act as co-aggregation factors for bacterial adhesion, studies of food-related biofilms have been limited to single-species biofilms and short biofilm formation periods. To assess the contribution of flagella and flagellum-based motility to adhesion and biofilm formation, two Salmonella and E. coli mutants with different flagellar phenotypes were produced: the fliC mutants, which do not produce flagella, and the motAB mutants, which are non-motile. The ability of wild-type and mutant strains to form biofilms was compared, and their relative fitness was determined in two-species biofilms with other foodborne pathogens. Our results showed a defective and significant behavior of E. coli in initial surface colonization (p < 0.05), which delayed single-species biofilm formation. Salmonella mutants were not affected by the ability to form biofilm (p > 0.05). Regarding the effect of motility/flagellum absence on bacterial fitness, none of the mutant strains seems to have their relative fitness affected in the presence of a competing species. Although the absence of motility may eventually delay initial colonization, this study suggests that motility is not essential for biofilm formation and does not have a strong impact on bacteria’s fitness when a competing species is present.

Research – An outbreak of Salmonella Typhimurium associated with the consumption of raw liver at an Eid al-Adha celebration in Wales (UK), July 2021

Cambridge.org

Abstract

In July 2021, Public Health Wales received two notifications of salmonella gastroenteritis. Both cases has attended the same barbecue to celebrate Eid al–Adha, two days earlier. Additional cases attending the same barbecue were found and an outbreak investigation was initiated. The barbecue was attended by a North African community’s social network. On same day, smaller lunches were held in three homes in the social network. Many people attended both a lunch and the barbecue. Cases were defined as someone with an epidemiological link to the barbecue and/or lunches with diarrhoea and/or vomiting with date of onset following these events. We undertook a cohort study of 36 people attending the barbecue and/or lunch, and a nested case-control study using Firth logistic regression. A communication campaign, sensitive towards different cultural practices, was developed in collaboration with the affected community. Consumption of a traditional raw liver dish, ‘marrara’, at the barbecue was the likely vehicle for infection (Firth logistic regression, aOR: 49.99, 95%CI 1.71–1461.54, p = 0.02). Meat and offal came from two local butchers (same supplier) and samples yielded identical whole genome sequences as cases. Future outbreak investigations should be relevant to the community affected by considering dishes beyond those found in routine questionnaires.

Research – Legal Regulation of Whole Genome Sequencing of Listeria monocytogenes in the Food Industry: Challenges, Attitudes, Possibilities

SSRN

Abstract

This report presents the outcome of legal research conducted under the aegis of the project ‘Food Safety with High Precision—Pathogenomics for the Food Industry’ (short title: PathoSeq). A central objective of the PathoSeq project has been to prepare the Norwegian food industry for challenges accompanying the introduction of whole genome sequencing (WGS) of foodborne bacteria. The report elucidates the legal rules that may affect the implementation of WGS of bacterial pathogens in the food industry, using Listeria monocytogenes (Lm) as a case study. While the report focuses predominantly on the Norwegian context, account is also taken of the experiences and practices of certain other European states, particularly Austria, in light of EU food safety rules. Three key issues are canvassed: (i) the role of WGS data in assessing the safety of food; (ii) access by food safety authorities to WGS data, or to isolates on which to perform WGS, from the food industry; and (iii) food business operators’ ability to receive Lm isolates and sequences held by the authorities. A special feature of the report is that it builds on, and presents, an extensive mapping of stakeholder perspectives on these issues and, more generally, on potentials, hindrances and needs in respect of mitigating Lm-related risk through WGS technology.