Cyclospora Cayetanensis-Major Outbreaks from Ready to Eat Fresh Fruits and Vegetables

Cyclospora cayetanensis is a coccidian protozoan that causes cyclosporiasis, a severe gastroenteric disease, especially for immunocompromised patients, children, and the elderly. The parasite is considered as an emerging organism and a major contributor of gastroenteritis worldwide. Although the global prevalence of cyclosporiasis morbidity and mortality has not been assessed, global concern has arisen since diarrheal illness and gastroenteritis significantly affect both developing countries and industrialized nations. In the last two decades, an increasing number of foodborne outbreaks has been associated with the consumption of fresh produce that is difficult to clean thoroughly and is consumed without processing. Investigations of these outbreaks have revealed the necessity to increase the awareness in clinicians of this infection, since this protozoan is often ignored by surveillance systems, and to establish control measures to reduce contamination of fresh produce. In this review, the major cyclosporiasis outbreaks linked to the consumption of ready to eat fresh fruits and vegetables are presented

Effect of co-culture with enterocinogenic E. faecium on L. monocytogenes key virulence gene expression

The aim of the present study was to assess the expression of key virulence genes during co-culture of L. monocytogenes with a bacteriocinogenic E. faecium strain in liquid growth medium. For that purpose, BHI broth was inoculated with 7 log CFU·mL–1 L. monocytogenes and 4, 5 or 6 log CFU·mL–1 E. faecium. Sampling took place after 8 and 24 h of incubation, corresponding to the maximum and minimum of enterocin production, respectively. The RNA was extracted, stabilized and expression of prfA, sigB, hly, plcA, plcB, inlA, inlB, inlC and inlJ, was assessed by RT-qPCR. Most of the genes were downregulated during co-culture at 5 °C. Moreover, a statistically significant effect of the inoculum level was evident in most of the cases. On the contrary, no effect on the transcription level of most of the genes was observed during co-culture at 37 °C

Effect of Lemongrass Essential Oil Vapors on Microbial Dynamics and Listeria monocytogenes Survival on Rocket and Melon Stored under Different Packaging Conditions and Temperatures

The aim of the present study was to examine the effect of lemongrass essential oil vapors on the dynamics of surface microbiota and L. monocytogenes growth on rocket and melon under different packaging conditions and storage temperature. For that purpose, rocket and melon were placed on Expanded Polystyrene (EPS) trays, sprayed with L. monocytogenes to a population of 4.5–5.0 log CFU·g−1, packaged using microperforated Oriented Polypropylene (OPP) film in either air or Microperforated Active Modified Atmosphere (MAMA) (initial atmosphere 5% O2, 10% CO2) including a Whatman paper containing the essential oil, without contact with the product, and stored at 0, 5, 10, and 15 °C. Application of lemongrass exhibited a bactericidal effect on enterococci and a fungistatic effect on yeast-mould populations but only during air storage of rocket. The former took place at all temperatures and the latter only at 10 and 15 °C. No effect on shelf life of both products was recorded. However, an important effect on the sensorial properties was observed; during the first 4–5 days of storage both products were organoleptically unacceptable. Regarding MAMA packaging, it affected only Pseudomonas spp. population resulting in a reduction of 1–2 log CFU·g−1 in both products

Newly Developed System for the Robust Detection of Listeria monocytogenes Based on a Bioelectric Cell Biosensor

Human food-borne diseases caused by pathogenic bacteria have been significantly increased in the last few decades causing numerous deaths worldwide. The standard analyses used for their detection have significant limitations regarding cost, special facilities and equipment, highly trained staff, and a long procedural time that can be crucial for foodborne pathogens with high hospitalization and mortality rates, such as Listeria monocytogenes. This study aimed to develop a biosensor that could detect L. monocytogenes rapidly and robustly. For this purpose, a cell-based biosensor technology based on the Bioelectric Recognition Assay (BERA) and a portable device developed by EMBIO Diagnostics, called B.EL.D (Bio Electric Diagnostics), were used. Membrane engineering was performed by electroinsertion of Listeria monocytogenes homologous antibodies into the membrane of African green monkey kidney (Vero) cells. The newly developed biosensor was able to detect the pathogen’s presence rapidly (3 min) at concentrations as low as 102 CFU mL−1, demonstrating a higher sensitivity than most existing biosensor-based methods. In addition, lack of cross-reactivity with other Listeria species, as well as with Escherichia coli, was shown, thus, indicating biosensor’s significant specificity against L. monocytogenes

Effect of different conditions on listeria monocytogenes biofilm formation and removal

Listeria monocytogenes poses a major risk for the safety of food products due to the ability to persist in food products and process line surfaces as biofilm. In this work, we investigated the L. monocytogenes biofilms in relation to development factors and possible control under different conditions. In particular, the ability of six strains of L. monocytogenes from vegetable and animal sources to form biofilms was evaluated on glass or polystyrene substrates under different temperatures (15, 30 and 37°C) and availability of nutrients, by using rich (BHI) or poor (HTM) growth media. Moreover, the effectiveness of three commonly used sanitizers (benzalkonium chloride, sodium hypochlorite and hydrogen peroxide) was compared to eradicate established biofilms. Our results showed that starved conditions, hydrophilic surfaces, and high temperatures increased the L. monocytogenes ability to produce biofilms. In general, benzalkonium chloride was the most effective chemical to remove established biofilms

Redox potential analysis for activated carbon using B.EL.D™ technology: A novel application

Assessing the effectiveness of activated carbon is essential for the optimal operation of water treatment systems. Traditional evaluation methods, although precise, are typically labor-intensive and require complex equipment This study introduces a novel application of the B.EL.D™ device, utilizing redox potential measurements to gauge the activation level of carbon filters—an approach not previously employed. We hypothesized that redox potential is a reliable indicator of activated carbon's performance, a hypothesis that was rigorously validated through extensive testing against the standard iodine number test (ASTM D4607). Our analysis included both control and operational samples from ongoing water treatment processes over two years, confirming a definitive correlation between redox potential and carbon's adsorptive capacity. The findings demonstrate the potential of our method as a rapid, accurate, and cost-effective alternative to current testing practices. Currently under patent consideration, this study marks a significant advancement towards improving the assessment of activated carbon filters, providing an efficient pathway for water treatment facilities and establishing the foundation for a predictive maintenance model