Background: Hand hygiene is important for interrupting transmission of viruses through hands. Effectiveness of alcohol-based hand disinfectant has been shown for bacteria but their effectiveness in reducing transmission of viruses is ambiguous.Aim: To test efficacy of alcohol hand disinfectant against human enteric and respiratory viruses and to compare efficacy of an alcohol-based hand disinfectant and handwashing with soap and water against norovirus.Methods: Efficacies of a propanol and an ethanol-based hand disinfectant against human enteric and respiratory viruses were tested in carrier tests. Efficacy of an alcohol-based hand disinfectant and handwashing with soap and water against noroviruses GI. 4, GII. 4, and MNV1 were tested using finger pad tests.Findings: The alcohol-based hand disinfectant reduced the infectivity of rotavirus and influenza A virus completely within 30 s whereas poliovirus Sabin 1, adenovirus type 5, parechovirus 1, and MNV1 infectivity were reduced <3 log(10) within 3 min. MNV1 infectivity reduction by washing hands with soap and water for 30 s (>3.0 +/- 0.4 log(10)) was significantly higher than treating hands with alcohol (2.8 +/- 1.5 log(10)). Washing with soap and water for 30 s removed genomic copies of MNV1 (>5 log(10)), noroviruses GI. 4 (>6 log(10)), and GII. 4 (4 log(10)) completely from all finger pads. Treating hands with propanol-based hand disinfectant showed little or no reduction to complete reduction with mean genomic copy reduction of noroviruses GI. 4, GII. 4, and MNV1 being >2.6, >3.3, and >1.2 log(10) polymerase chain reaction units respectively.Conclusions: Washing hands with soap and water is better than using alcohol-based hand disinfectants in removing noroviruses from hands. (C) 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Transfer of Listeria monocytogenes was investigated from surface-inoculated cooked ham to commercial slicing machine surfaces, from spot-inoculated ham to the slicing machine blade, and vise-versa from a contaminated slicer to clean ham. With balances the proportion transfer from the source to the various destinations were investigated as well as the kinetics of transfer during successive slicing, using a difference equation. For inoculated ham, the transfer ratio to the machine was highest to the table (0.06), followed by the handle board (0.01) and plate, guard, and front and back of the blade (<0.001). The transfer ratio of the pathogen from spot-inoculated ham to back and front of the slicer blade was 0.006 and 0.01 (respectively), which was significantly (P < 0.05) higher than the transfer from surface-inoculated ham (<0.001). The transfer ratio from the slicer to clean ham was individually calculated for each of 39-40 ham slices. The mean transfer ratio of the first slice to the penultimate slice was around 0.04 for both inoculum levels (8 or 6 log CFU/ham). For the end slice, a very high transfer ratio of 0.42-0.74 (for the high and moderate inoculum level, respectively) was observed due to contact of one side of the slice to the handle board which has a large contact area (84 cm(2)) with the ham during the whole slicing process. A transfer model was developed, where the numbers of L monocytogenes (CFU) on each ham slice and the remaining organisms on the slicer surfaces were calculated assuming a constant transfer ratio. Based on the model calculation, a linear reduction of the log pathogen concentration on the machine surface and therefore also on the consecutive ham slices was observed as a function of the slice number. (C) 2014 Elsevier Ltd. All rights reserved.

The fate of 3 different Listeria monocytogenes strains (Scott A, 2F and 6E) was studied independently in brine and on factory-scale Gouda cheeses that had been submerged in brine that was artificially contaminated with these individual strains. Viable numbers of L. monocytogenes in the brine decreased during brining (0, 1, 2.9 and 8.9 d). L. monocytogenes was enumerated on the surface of Gouda cheese directly after brining and over 26 weeks of ripening at 12.5 degrees C. Transfer of L. monocytogenes from brine to cheese during brining was limited. L. monocytogenes was detected in the outer layer of Gouda cheese but not in the centre directly after brining or during ripening. Throughout the ripening period, the viable numbers of L. monocytogenes declined significantly. This study adds to the understanding of the fate of L. monocytogenes in brine and on Gouda cheese, and demonstrates that growth of L. monocytogenes on Gouda cheese is not supported following contamination during brining. (C) 2014 Elsevier Ltd. All rights reserved.

To simulate food contact surfaces with pits or cracks, stainless steel plates with grooves (depths between 0.2 and 5 mm) were constructed. These plates were artificially contaminated with Listeria monocytogenes in clean conditions, with organic soiling, or after 14 days of biofilm formation after which inactivation of the pathogen by Suma Tab D4 (sodium dichloroisocyanurate, 240 and 300 mg/liter), Suma Bac D10 (quaternary ammonium compound, 740 mg/liter), and bacteriophage suspension (Listex P100) was determined. Both chemical disinfectants performed well in suspension tests and in clean carrier tests according to the European standard with a reduction of more than 5 and 4 log units, respectively, of Listeria cells after 5 min of contact time. However, for the plates with grooves, the reduction could not meet the standard requirement, although a higher reduction of L. monocytogenes was observed in the shallow grooves compared with the deeper grooves. Furthermore, presence of food residues and biofilm reduced the effect of the disinfectants especially in the deep grooves, which was dependent on type of food substrate. Bacteriophages showed the best antimicrobial effect compared with the chemical disinfectants (sodium dichloroisocyanurate and quaternary ammonium compound) in most cases in the shallow grooves, but not in the deep grooves. The chlorine based disinfectants were usually less effective than quaternary ammonium compound. The results clearly demonstrate that surfaces with grooves influenced the antimicrobial effect of the chemical disinfectants and bacteriophages because the pathogen is protected in the deep grooves. The use of bacteriophages to inactivate pathogens on surfaces could be helpful in limited cases; however, use of large quantities in practice may be costly and phage-resistant strains may develop.

The essential oil of the resin of Pistacia lentiscus var. Chia (mastic oil) was studied in vitro against a wide range of foodborne pathogenic and spoilage microorganisms with a diffusion and a dilution method. Furthermore its chemical composition was analyzed by means of Gas Chromatography-Mass Spectrometry (GC-MS) and the possibility of using the essential oil in food preservation was discussed. The Minimal Inhibitory Concentrations (MICs) of mastic oil were estimated for 6 species of bacteria (Bacillus cereus, Campylobacter jejuni, Clostridium perfringens, Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus), 2 species of yeasts (Saccharomyces cerevisiae and Zygosaccharomyces bailii) and 3 species of fungi (Penicillium roquefortii, Aspergillus flavus and Eurotium amstelodami). GC-MS analysis revealed a chemotype dominated by monoterpenes, principally alpha-pinene and beta-myrcene comprising more than 90 % of the mastic oil. Both methods showed Cl. perfringens as the most susceptible microorganism followed by S. cerevisiae and Z. bailii. With the exception of C. jejuni, Gram-positive were found to be more susceptible to the essential oil than Gram-negative microorganisms and all fungi appeared very resistant to mastic oil. Based on the observed MICs, the contribution of mastic oil to the preservation of bakery/confectionary products at the amounts currently used for flavoring purposes is likely to be negligible.

Viruses are the most common cause of infectious disease acquired in the indoor environment in hospitals, schools and households causing considerable impact on human health. Transmission of enteric and respiratory viruses is assumed to occur predominantly direct from person to person followed by indirect transmission through contaminated fomites/surfaces. The risk of infection resulting from transmission through contaminated surfaces depends on a number of factors, including the level of shedding of infective particles, their stability on surfaces and resistance to decontamination procedures, fractions transmitted per contact and the dose required for infection. Among the enteric viruses, human noroviruses (NoVs) and rotaviruses are most notorious for causing outbreaks of gastroenteritis within hospitals, nursing homes and cruise ships and are significant cause of hospitalization. Besides human NoV and rotavirus, other enteric viruses like enteroviruses and parechoviruses, and respiratory viruses like influenza and adenovirus may also be transmitted through contaminated surfaces.

Human noroviruses are the major cause of acute gastroenteritis in the western world and contaminated hands are important routes for their transmission. Quantitative data on transfer during contact with surfaces and food are scarce but necessary for quantitative risk assessments. Therefore, we studied the transfer of PCR detectable units (PCRU) of human NoVs representatives of the main genogroups (GI.4 and GII.4) from fingers to fomites and vice versa. These data were compared to infectivity and PCRU data for the cultivable model murine norovirus (MNV1).

The first isolation methods for the detection of Listeria spp. were based on the direct culture of samples on simple agar media, but isolation of the pathogenic Listeria monocytogenes was difficult. In time, new media were developed based on a variety of selective and elective agents in enrichment and isolation enumeration media. The recovery of low numbers of L. monocytogenes from foods and environmental samples requires the use of enrichment cultures followed by selective plating. In this chapter the development of selective media, including so-called differential media on which L. monocytogenes can be distinguished from other, non-pathogenic, species, are discussed. Little attention is paid to pre-enrichment media, recommended for the recovery of injured organisms, because in our opinion the presence of listeriae in products that receive a listericidal treatment is mainly due to post-process contamination. The introduction of chromogenic media, such as agar Listeria according to Ottoviani and Agosti (ALOA) allows the recovery of Listeria and L. monocytogenes from a variety of foods with relative ease.

The effects of organic material and biofilm formation on the efficacy of Suma Tab D4 chlorine tablets and Suma Bac D10 quaternary ammonium compound (QAC) against Listeria monocytogenes was determined in suspension and on stainless steel and polystyrene surfaces according to standard disinfectant test methodology. Exposure to 200 and 740 mg L-1 QAC and to 150 mg L-1 active chlorine resulted in a > 5.0 log10 CFU mL-1 and > 5.0 log10 CFU/coupon reduction of six L. monocytogenes strains within one minute, in suspension tests, and on stainless steel surfaces, respectively. Additionally, there was a reduction by as much as 5 log10 CFU/coupon or 5 log10 CFU/well of reference strains EGDe and Scott A biofilms within five minutes on stainless steel and polystyrene surfaces. Organic material, added as bovine serum albumin at 0.3% (w/v) completely prevented the inactivation of L. monocytogenes in 150 mg L-1 chlorine, while reductions of only 0.6 +- 0.1 log10 CFU mL-1 were recorded in the presence of UHT milk at 3% (v/v). In contrast, reductions of 5 log10 CFU mL-1 were recorded within one minute on exposure to 740 mg L-1 QAC in the presence of 0.3% (w/v) bovine serum albumin and within two minutes in the presence of 20 % (v/v) UHT milk. Although Suma D4 chlorine tablets and Suma Bac D10 QAC are effective listericidal agents at recommended concentrations, Suma Tab D4 chlorine efficacy against L. monocytogenes is impaired by the presence of low concentrations of organic material, while Suma Bac D10 QAC maintains its listericidal activity in high organic loads.

Steam meals are ready-to-eat meals composed of raw and semi-cooked ingredients, which get cooked while microwave heating. In this study, an Indian style meal was selected, Chicken Tandoori, from two different producers. These meals were first evaluated with the Risk Ranger® to identify the main foodborne pathogens risks, which were Listeria monocytogenes, Salmonella Typhimurium and Bacillus cereus. Thereafter, quantitative microbiology was applied using different models and verified with growth and inactivation challenge tests. It was observed that the gamma model and the ComBase program® showed very similar results. However, in some cases the results obtained with the challenge tests showed different results. The information gathered was used to create different scenarios which indicate how to manage the risks by setting Performance Objectives during the different stages of the food chain of this product and hence reaching a suggested Food Safety Objective.

Antibacterial polymers suitable for coating applications without leaching of the biocidal component have been obtained by UV copolymerization of acrylic resins with acrylic monomers containing quaternary ammonium moieties. Suitable reactive biocides, based on quaternary ammonium monomers (QAMs), endowed with undecylacryloyl group and alkyl chains with 2 (QAM-C2), 8 (QAM-C8), and 16 (QAM-C16) carbon atoms have been synthesized. Aqueous solutions of QAMs showed biocidal activity against Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes strains both in suspension and adhered to stainless steel surfaces. QAM-C16 and QAM-C8 evidenced higher activity toward bacteria in suspension and on stainless steel, respectively. The QAMs have shown sufficient reactivity to be copolymerized, by UV irradiation, with a commercial urethane acrylic resin for coating. Bioactivity tests, performed on free films of crosslinked coatings containing 1% of copolymerized QAM, have shown an increasing inactivation effect in the order of magnitude L. monocytogenes, E. coli, S. aureus with a maximum activity of the QAM-C8.

The purpose of this study was to determine the prevalence of Campylobacter in fresh vegetables and fruits at retail level in the Netherlands, and to estimate its implications on the importance of vegetables and fruits as risk factor for campylobacteriosis. Thirteen of the 5640 vegetable and fruit samples were Campylobacter positive, resulting in a prevalence of 0.23% (95% confidence interval (Cl): 0.12–0.39%). The prevalence of packaged products (0.36%, 95% Cl: 0.17–0.66) was significantly higher than of unpackaged products (0.07; 95% Cl: 0.01–0.27). No statistical differences were found between seasons. Combining the mean prevalence found in this study with data on the consumption of vegetables and fruits, an exposure of 0.0048 campylobacters ingested per person per day in the Netherlands by transmission via vegetables and fruits, was calculated. This exposure, as input in a Beta-Poisson dose–response model, resulted in an estimated number of 5.3 × 105 cases of infection with Campylobacter per year for the whole Dutch population. This constitutes the consumption of raw vegetables and fruits, especially when packaged, to be a risk factor for Campylobacter infections.

Survival of Listeria monocytogenes on a conveyor belt material with or without antimicrobial additives, in the absence or presence of food debris from meat, fish and vegetables and at temperatures of 10, 25 and 37°C was investigated. The pathogen survived best at 10°C, and better at 25°C than at 37°C on both conveyor belt materials. The reduction in the numbers of the pathogen on belt material with antimicrobial additives in the first 6h at 10°C was 0.6 log unit, which was significantly higher (P<0.05) than the reduction of 0.2 log unit on belt material without additives. Reductions were significantly less (P<0.05) in the presence of food residue. At 37°C and 20% relative humidity, large decreases in the numbers of the pathogen on both conveyor belt materials during the first 6h were observed. Under these conditions, there was no obvious effect of the antimicrobial substances. However, at 25°C and 10°C and high humidity (60–75% rh), a rapid decrease in bacterial numbers on the belt material with antimicrobial substances was observed. Apparently the reduction in numbers of L. monocytogenes on belt material with antimicrobial additives was greater than on belt material without additives only when the surfaces were wet. Moreover, the presence of food debris neutralized the effect of the antimicrobials. The results suggest that the antimicrobial additives in conveyor belt material could help to reduce numbers of microorganisms on belts at low temperatures when food residues are absent and belts are not rapidly dried.

Cronobacter spp. is an opportunistic pathogen possibly occurring in many different foods and environments. This study reports results from a broad survey of foods manufactured or marketed in The Netherlands, including relevant non-food environments, conducted over a 5-years period (2001–2005). Using a specifically designed real-time polymerase chain reaction method for confirmation, Cronobacter spp. was isolated from milk powders (7/175), powdered formulae for consumers <1year (8/395), formulae for consumers >1year (1/5), other powdered instant products (1/182), dry cereals (6/123), raw minced meats (7/222), vegetables (2/47), spices (1/28), human faeces (1/98), and human skin (1/116) samples.

This study aimed to investigate the effect of processed soya bean, during the successive stages of tempe fermentation and different fermentation times, on adhesion of enterotoxigenic Escherichia coli (ETEC) K88 to intestinal brush border cells as well as Caco-2 intestinal epithelial cells; and to clarify the mechanism of action.Tempe was prepared at controlled laboratory scale using Rhizopus microsporus var. microsporus as the inoculum. Extracts of raw, soaked and cooked soya beans reduced ETEC adhesion to brush border cells by 40%. Tempe extracts reduced adhesion by 80% or more. ETEC adhesion to Caco-2 cells reduced by 50% in the presence of tempe extracts. ETEC K88 bacteria were found to interact with soya bean extracts, and this may contribute to the observed decrease of ETEC adhesion to intestinal epithelial cells.Fermented soya beans (tempe) reduce the adhesion of ETEC to intestinal epithelial cells of pig and human origin. This reduced adhesion is caused by an interaction between ETEC K88 bacteria and soya bean compounds.The results strengthen previous observations on the anti-diarrhoeal effect of tempe. This effect indicates that soya-derived compounds may reduce adhesion of ETEC to intestinal cells in pigs as well as in humans and prevent against diarrhoeal diseases.