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Aim: To describe the development of a dysphagia management intervention for elders with sarcopenic oropharyngeal dysphagia (OD). Methods: The intervention development was guided by the UK Medical Research Council framework for developing and evaluating complex interventions. The steps included identification of the problem theory, the evidence base, the theory underpinning the intervention, the expected change mechanisms and a first draft of an intervention manual. This involved literature reviews and involvement of stakeholders, experts, and members of the target group. Results: A manualized client-centered and activity-based intervention that integrates functional resistance training of skills essential for a safe and efficient swallowing during ingestion of daily meals was developed for elders with sarcopenic OD. The intervention is informed by occupational therapy theory, self-determination theory, motor learning and affordance theory, and international standards for OD diets. Conclusion: The development steps resulted in a multicomponent intervention ready for feasibility testing before examining intervention efficacy.

Detection of norovirus (NoV) and hepatitis A virus (HAV) on fruits and vegetables using current standard methodologies can be inefficient. Method optimisation focussing on ease, rapidity and increased viral RNA recovery is needed for efficient reverse transcription (RT)-qPCR detection of viruses. A simple and quick direct lysis method for RNA extraction was optimised (method A) to achieve increased viral RNA recovery and minimised RT-qPCR inhibition by increasing the volume of lysis buffer and inclusion of pectinase, Plant RNA Isolation Aid and OneStep PCR Inhibitor Removal Kit. Method A and an internal method structurally comparable to the ISO 15216 standard (method B) were compared for their efficiencies to recover viral RNA from the process controls, mengovirus (MC0) and murine norovirus (MNV), spiked in 13 types of fruits, vegetables, compound foods or seeds/nuts. All extracts (> 61) were also analysed for RT-qPCR inhibition and for natural contamination of NoV and HAV. The overall mean extraction efficiencies of MC0 and MNV were 36 ± 31 and 44 ± 38%, respectively, for method A and 9 ± 16 and 5 ± 11%, respectively, for method B. Inhibition of RT-qPCR amplification of RNA from NoV genogroup (G)I, NoV GII, and HAV ranged from 5 ± 10 to 13 ± 14% for method A and 34 ± 36 to 48 ± 40% for method B. NoV GII was detected in samples of strawberries and seaweed processed by both methods. In conclusion, the new direct lysis method showed an overall better performance compared to the modified ISO 15216 standard and should be validated for implementation in analysis of viruses in foods of plant origin.

Aims The association between socioeconomic position and cardiovascular disease has not been well studied in patients with type 2 diabetes. We aimed to examine the association between socioeconomic position and first-time major adverse cardiovascular events (MACE) in patients with type 2 diabetes. Methods and results Through the Danish nationwide registers, we identified all residents with newly diagnosed type 2 diabetes between 2012 and 2017. Based on sex-stratified multivariable cause-specific Cox regression models, we calculated the standardized absolute 5-year risk of the composite outcome of first-time myocardial infarction, stroke, or cardiovascular mortality (MACE) according to income quartiles. A total of 57 106 patients with type 2 diabetes were included. During 155 989 person years, first-time MACE occurred in 2139 patients. Among both men and women, income was inversely associated with the standardized absolute 5-year risk of MACE. In men, the 5-year risk of MACE increased from 5.7% [95% confidence interval (CI) 4.9–6.5] in the highest income quartile to 9.3% (CI 8.3–10.2) in the lowest income group, with a risk difference of 3.5% (CI 2.4–4.7). In women, the risk of MACE increased from 4.2% (CI 3.4–5.0) to 6.1% (CI 5.2–7.0) according to income level, with a risk difference of 1.9% (CI 0.8–2.9). Conclusion Despite free access to medical care in Denmark, low-socioeconomic position was associated with a higher 5-year risk of first-time MACE in patients with incident type 2 diabetes. Our results suggest prevention strategies could be developed specifically for patients with low-socioeconomic position.

Tonsils in the oral cavity are an important source of contamination during pig slaughter, but have not received as much attention as faecal contamination. In the present study, ten pigs were sampled from tonsils, faeces and three different areas on each carcass. The samples were analysed by both culturing of Escherichia coli and Yersinia enterocolitica and by 16S rRNA gene sequencing to characterize the bacterial communities. Comparing culture data from deep tonsil tissue and tonsil surface showed similar numbers of E. coli but significantly higher numbers of Y. enterocolitica in the deep tissue samples. Microbiota analysis showed similar bacterial communities in the two sample types at phylum level, while comparison at genus level showed significant differences between the relative abundance of several genera in the two sample types. The finding of a significantly higher relative abundance of Yersinia in tonsil tissue compared to tonsil surface supported the culture analysis. The microbiota analysis also investigated characteristics of the bacterial community that could discriminate bacterial transfer from tonsils and faeces to the carcass during slaughter. The microbiota analyses demonstrated that Fusobacteria and Proteobacteria are the most abundant phyla in tonsils, while Firmicutes showed the highest relative abundance in faeces. The dominating phylum on carcasses was Proteobacteria. Besides Proteobacteria, the swabbing area on the forepart of the carcass, showed a higher relative abundance of Firmicutes and Fusobacteria compared to swabbing areas on the rear part and mid-section of the carcass. Principal coordinate analysis showed clear clustering of samples based on sample source (tonsils, faeces and carcass). Carcass swab samples from the forepart tended to cluster closer to the tonsil samples compared to carcass swab samples from the rear part and mid-section. Identification of the genera Fusobacterium, Moraxella, Actinobacillus and non-E. coli genera of the family Enterobacteriaceae in carcass swabs could indicate tonsil contamination, while faecal contamination would more likely include higher prevalence of bacteria belonging to the class of Clostridia. The present study supports that it is possible to identify bacterial groups that are indicative for either tonsil or faecal carcass contamination. The level and composition of Enterobacteriaceae on the carcasses did, however, indicate that other sources of meat contamination than tonsils and faeces may be important, such as the process environment.

The resistance of Salmonella to the harsh conditions occurring in shelf-stable dry fermented sausages (DFS) poses a food safety challenge for producers. The present study aimed to model the behaviour of Salmonella in acid (with starter culture) and low-acid (without starter culture) DFS as a function of aw and storage temperature in order to build a decision supporting tool supporting the design of a corrective storage strategy to enhance the safety of DFS. Salmonella spp. were inoculated in the raw meat batter at ca. 6 Log cfu/g with a cocktail of 3 strains (CTC1003, CTC1022 and CTC1754) just before mixing with the other ingredients and additives. After stuffing, sausages were fermented and ripened following industrial processing conditions. Different drying-times were applied to obtain three batches with different aw (0.88, 0.90 and 0.93). Afterwards, DFS were stored at 4, 8, 15 and 25 °C for a maximum of three months and Salmonella spp. were periodically enumerated. The Weibull model was fitted to Log counts data to estimate inactivation kinetic parameters. The impact of temperature and aw on the primary inactivation parameters was evaluated using a polynomial equation. The results of the challenge tests showed that Salmonella spp. levels decreased during storage at all the assayed conditions, from 0.8 Log (in low-acid DFS at 4 °C) up to 6.5 Log (in acid DFS at 25 °C). The effect of both aw and temperature was statistically significant. Delta (δ) parameter decreased by decreasing aw and increasing temperature, while the shape (p) parameter ranged from above 1 (concave) at 10 °C to below 1 at 25 °C (convex). A common secondary model for the p parameter was obtained for each type of DFS, acid and low-acid, indicating that acidification during the production of DFS affected the time for the first Log reduction (δ) during the subsequent storage, but not the overall shape (p parameter) of the inactivation. The developed models covered representative of real conditions, such as Salmonella contamination in the raw materials and its adaptation to the harsh processing conditions. The good predictive performance shown when applying the models to independent data (i.e. up to 80% of the predictions within the ‘Acceptable Simulation Zone’ for acid sausages) makes them a suitable and reliable risk management tool to support manufacturers to assess and design a lethality treatment (i.e. corrective storage) to enhance the Salmonella inactivation in the product before DFS are released to the market.

Listeria monocytogenes is a potentially fatal foodborne pathogen that can be found in various ready-to-eat (RTE) products. It tolerates adverse conditions such as high salt concentrations and refrigerated storage, thus, the elimination of the pathogen in food processing often relies on heat processing. The objective of this study was to create a model to predict the effect of salt on heat tolerance of L. monocytogenes in meat and seafood products during heat treatments conducted at 57 to 65 °C to reduce numbers by ≥3 log10 cycles. Salt concentrations, up to 6% in the water phase (WPS%), were applied to cover a variety of lightly salted RTE meat and seafood products. The experimental work involved samples of ground pork tenderloin, ground chicken breast fillet and skinned, ground salmon fillet adjusted to different WPS% i.e., 3.6 and 5.2 WPS% for pork samples, 2.0, 3.0, 3.5 and 6.0 WPS% for chicken samples and 3.0 and 6.0 WPS% for salmon samples. All samples were inoculated with late-stationary phase L. monocytogenes cultures. For pork samples, a two-strain mixture of a pork isolate (MS22254) and an environmental isolate (MS22246) was applied. For chicken and salmon samples, a seafood isolate (MS22258) and isolate MS22246 was applied as single cultures. Samples were vacuum-packed in sterile bags, immerged in water bath, and held at constant temperatures of 57, 60 and 65 °C for pork samples and 58, 61 and 62.5 °C for chicken and salmon samples. For survivor curves, where at least 3 log10-reduction were obtained, heat tolerance was expressed as decimal reduction times, D-values. D-values were observed to increase with increasing WPS%. The effect of salt on heat tolerance of L. monocytogenes was defined as the relative increase (RI-value) in D-value obtained when salt had been added to the food. The effect of WPS% on RI-values was independent of heating temperatures, foods and strains. For secondary modelling, RI-values were transformed using the natural logarithm, ln(RI) and fitted to a linear model as a function of WPS%. Model validation, with 56 independent values collected from the scientific literature, resulted in bias and accuracy factors of 0.89 and 1.26, respectively, suggesting acceptable performance with tendency to slightly under-predict. The developed predictive model can be used to guide the design of heat processes for manufacturers of lightly preserved and mildly processed meat and seafood products requiring more than 3 log10 reduction of L. monocytogenes to ensure safety.

In Denmark, the pig slaughterhouses have a daily input of pigs infected and/or contaminated with Salmonella, and the slaughter hygiene has major influence on the level of Salmonella contamination on the meat leaving the slaughterhouse. However, the relationship between the effect of improved hygiene performance and the consequential reduction of human health risk has not been estimated so far. In this study, swab samples from 2702 pig carcasses were collected, originally for other purposes, from five large Danish slaughterhouses in a period from 2005 to 2007, covering all seasons of the year. The samples were analysed quantitatively for E. coli and semi-quantitatively for Salmonella. A positive association between the number of E. coli on carcasses and the prevalence of Salmonella positive carcasses was shown. For carcasses positive for Salmonella, a positive association was also shown between the number of E. coli and the number of Salmonella on the carcass. As no biological association has been reported between faecal shedding of E. coli and presence of Salmonella, the relationship was considered to be associated with the level of faecal contamination. The positive association between E. coli and Salmonella was used as basis for developing a quantitative risk assessment model for Salmonella, using the level E. coli as model input. The model output associated the hygiene performance with a relative risk estimate of human salmonellosis. The overall objective was to develop a decision support tool that can be used to support risk-based hygiene interventions in pig slaughterhouses.

Background The Eating Assessment Tool (EAT-10) is increasingly used to screen for self-perceived oropharyngeal dysphagia (OD) in community-dwelling elders. A summated EAT-10 total score ranges from 0 to 40, with a score ≥ 3 indicative of OD. When using cut-points of a summated score, important requirements for the measurements are specific objectivity, validity, and reliability. Analysis by the Rasch model allows investigation of whether scales like EAT-10 satisfy these requirements. Currently, a few studies have found that EAT-10 responses from clinical populations with OD do not adequately fit the Rasch model. Purpose The aim of this study was to determine whether measurements by EAT-10 fit the Rasch model when applied in screening self-perceived OD in non-clinical populations. Methods Secondary analysis was conducted on data from a cross-sectional survey of community-dwelling elders living in a municipal district of Tokyo, Japan, in which 1875 respondents completed the Japanese version of EAT-10 (J-EAT-10). Data were cleaned and recoded for the purpose of the analysis in this study, which resulted in inclusion of J-EAT-10 responses from 1144 respondents. Data were analyzed using RUMM2030 and included overall model fit, reliability, unidimensionality, threshold ordering, individual item and person fits, differential item functioning, local item dependency, and targeting. Results The analysis identified that the response categories from zero to four were not used as intended and did not display monotonicity, which necessitated reducing the five categories to three. Considerable floor effect was demonstrated and there was an inappropriate match between items’ and respondents’ estimates. The person separation reliability (PSI = 0.65) was inadequate, indicating that it is not possible to differentiate between different levels of OD. Several items displayed misfit with the Rasch model, and there were local item dependency and several redundant items. Conclusions J-EAT-10 performed less than optimally and exhibited substantial floor effect, low reliability, a rating scale not working as intended, and several redundant items. Different improvement strategies failed to resolve the identified problems. Use of J-EAT-10 in population-based surveys cannot therefore be recommended. For such purpose, alternative screening tools of self-perceived OD should be chosen or a new one should be developed and validated.

In a previous study, a model was developed to describe the transfer and survival of Salmonella during grinding of pork (Møller, C.O.A., Nauta, M.J., Christensen, B.B., Dalgaard, P., Hansen, T.B., 2012. Modelling transfer of Salmonella typhimurium DT104 during simulation of grinding of pork. Journal of Applied Microbiology 112 (1), 90-98). The robustness of this model is now evaluated by studying its performance for predicting the transfer and survival of Salmonella spp. and Listeria monocytogenes during grinding of different types of meat (pork and beef), using two different grinders, different sizes and different numbers of pieces of meats to be ground. A total of 19 grinding trials were collected. Acceptable Simulation Zone (ASZ), visual inspection of the data, Quantitative Microbiological Risk Assessment (QMRA), as well as the Total Transfer Potential (TTP) were used as approaches to evaluate model performance and to access the quality of the cross contamination model predictions. Using the ASZ approach and considering that 70% of the observed counts have to be inside a defined acceptable zone of ±0.5 log10CFU per portion, it was found that the cross contamination parameters suggested by Møller et al. (2012) were not able to describe all 19 trials. However, for each of the collected grinding trials, the transfer event was well described when fitted to the model structure proposed by Møller et al. (2012). Parameter estimates obtained by fitting observed trials performed at different conditions, such as size and number of pieces of meat to be ground, may not be applied to describe cross contamination of unlike processing. Nevertheless, the risk estimates, as well as the TTP, revealed that the risk of disease may be reduced when the grinding of meat is performed in a grinder made of stainless steel (for all surfaces in contact with the meat), using a well-sharpened knife and holding at room temperatures lower than 4°C.

Growth of Listeria innocua at 9 C was investigated in white cheeses manufactured from ultra-filtrate milk concentrate added varying amounts of skimmed milk powder, NaCl and glucono-delta-lactone. Characterization of the white cheese structures was performed using nuclear magnetic resonance(NMR) T2 relaxation parameters (relaxation times constants, relative areas and width of peaks) and their applicability as predictive factors for maximum specific growth rate, Ommax and log-increase in 6 weeks of L. innocua was evaluated by polynomial modeling. Inclusion of NMR parameters was able to increasethe goodness-of-fit of two basic models; one having pH, undissociated gluconic acid (GAu, mM) and NaCl (% w/v) as predictive factors and another having pH, GAu and aw as predictive factors. However, the best model fit was observed using Ommax as response for the model including pH, GAu, aw and Width T21revealing the lowest relative root mean squared errors of 14.0%. As the T2 relaxation population T21 is assigned to represent immobilized bulk water protons and the width T21 the heterogeneity of this water population, growth of L. innocua in white cheese seemed to be dependent on the heterogeneity of theimmobilized bulk water present in cheese.

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Aims: The aim of this study was to develop a model to predict cross-contamination of Salmonella during grinding of pork. Methods and Results: Transfer rates of Salmonella were measured in three experiments, where between 10 and 20 kg meat was ground into 200-g portions. In each experiment, five pork slices of about 200 g per slice were inoculated with 8–9 log-units of Salmonella Typhimurium DT104 and used for building up the contamination in the grinder. Subsequently, Salmonella-free slices were ground and collected as samples of c. 200 g minced pork. Throughout the process, representative samples were quantitatively analysed for Salmonella. A model suggested by Nauta et al. (2005) predicting cross-contamination of Campylobacter in poultry processing and two modified versions of this model were tested. Conclusions: The present study observed a tailing phenomenon of transfer of Salmonella during a small-scale grinding process. It was, therefore, hypothesized that transfer occurred from two environmental matrices inside the grinder and a model was developed. The developed model satisfactorily predicted the observed concentrations of Salmonella during its cross-contamination in the grinding of up to 110 pork slices. Significance and Impact of the Study: The proposed model provides an important tool to examine the effect of cross-contamination in quantitative microbial risk assessments and might also be applied to various other food processes where cross-contamination is involved.

The prevalence of Salmonella in fresh pork cuttings in Denmark in the years 2002 and 2006 was investigated at retail and compared with the retail supply pattern. A total of 1025 and 3473 samples were taken in 2002 from butcher's shops and supermarkets, respectively. The corresponding numbers in 2006 were 259 from butchers' shops and 628 from supermarkets. In 2002, 1.2% of all samples were positive for Salmonella; butchers' shops and supermarkets had 1.8% and 1.0% positive samples, respectively. The overall prevalence in 2006 was 4.2%, with prevalence of 8.1% and 2.6% for butchers' shops and supermarkets, respectively. Hence, increases around 3- to 5-fold were found. There was neither observed any parallel increase in Salmonella positive carcasses in Danish slaughterhouses during the study period, nor were any changes in supply routes towards slaughterhouses with higher prevalence observed, which could explain the apparent increase. We hypothesize that hygiene levels and ability to avoid cross-contamination and prevent growth of the organism, in the meat processing chain after slaughter were the most likely responsible factors. Results from this study indicate that the hygiene performance, particularly at retail, has a significant impact on the occurrence of Salmonella. This implies that there is no direct link between slaughterhouse Salmonella surveillance data and the level of Salmonella contamination at retail. To improve risk assessment of Salmonella in fresh pork meat, this study underlines the need for comprehensive retail data.

Three different Listeria monocytogenes strains, LO28 (a laboratory strain with truncated InlA), 4446 (a clinical isolate) and 7291 (a food isolate), were compared in a guinea-pig model designed to mimic food-borne exposure. The objectives were (1) to verify the applicability of the animal model for distinguishing between Listeria with different virulence properties and (2) to explore whether it was possible to reduce the required number of animals by dosing with mixed cultures instead of monocultures. Consistent with in vitro observations of infectivity in Caco-2 cells, faecal densities and presence in selected organs were considerably lower for LO28 than for the other two strains. Additionally, the animal study revealed a difference in prevalence in faeces as well as in internal organs between the clinical isolate and the food isolate, which was not reproduced in vitro. Dosage with monocultures of Listeria strains gave similar results as dosage with a mixture of the three strains; thus, the mixed infection approach was a feasible way to reduce the number of animals needed for determination of listerial virulence.

Microbiological limits are widely used in food processing as an aid to reduce the exposure to hazardous microorganisms for the consumers. However, in pork, the prevalence and concentrations of Salmonella are generally low and microbiological limits are not considered an efficient tool to support hygiene interventions. The objective of the present study was to develop an approach which could make it possible to define potential risk-based microbiological limits for an indicator, enterococci, in order to evaluate the risk from potential growth of Salmonella. A positive correlation between the concentration of enterococci and the prevalence and concentration of Salmonella was shown for 6640 pork samples taken at Danish cutting plants and retail butchers. The samples were collected in five different studies in 2001, 2002, 2010, 2011 and 2013. The observations that both Salmonella and enterococci are carried in the intestinal tract, contaminate pork by the same mechanisms and share similar growth characteristics (lag phase and maximum specific growth rate) at temperatures around 5–10 °C, suggest a potential of enterococci to be used as an indicator of potential growth of Salmonella in pork. Elevated temperatures during processing will lead to growth of both enterococci and, if present, also Salmonella. By combining the correlation between enterococci and Salmonella with risk modelling, it is possible to predict the risk of salmonellosis based on the level of enterococci. The risk model used for this purpose includes the dose–response relationship for Salmonella and a reduction factor to account for preparation of the fresh pork. By use of the risk model, it was estimated that the majority of salmonellosis cases, caused by the consumption of pork in Denmark, is caused by the small fraction of pork products that has enterococci concentrations above 5 log CFU/g. This illustrates that our approach can be used to evaluate the potential effect of different microbiological limits and therefore, the perspective of this novel approach is that it can be used for definition of a risk-based microbiological limit for enterococci. The limit for enterococci can then be used for development of a process hygiene criterion in cutting plants and retail butcher shops, with the purpose of reducing the risk of Salmonella for the consumer.

The present study had the purpose of demonstrating a positive correlation between enterococci and Salmonella in minced pork and beef. Data from 2001 to 2002 from retail minced pork and beef in Denmark were used and the association between concentration of enterococci and prevalence and concentration of Salmonella was examined. A total of 2187 and 2747 samples of minced pork and beef, respectively, were collected from butcher shops and supermarkets throughout the country. In pork, 2.1% of all samples were positive for Salmonella whereas 1.5% of beef samples were positive. Among samples with ≥100 CFU/g of enterococci, prevalence of Salmonella positive samples was 3.4%, which was significantly higher than 1.2% observed in minced meat with less than 100 CFU/g of enterococci (P

This study aimed to evaluate a cross contamination model1 for its capability of describing transfer of Salmonella spp. and L. monocytogenes during grinding of varying sizes and numbers of pieces of meats in two grinder systems. Data from 19 trials were collected. Three evaluation approaches were applied: i) Acceptable Simulation Zone method compared observed with simulated transfer, ii) each trial was fitted and parameters were integrated in a Quantitative Microbiological Risk Assessment model, iii) the Total Transfer Potential was calculated from fitted parameters. Risk estimates revealed that grinding was influenced by sharpness of grinder knife, specific grinder and grinding temperature.

A Nordic standard protocol for detection and enumeration of thermotolerant Campylobacter in food has been elaborated (NMKL 119, 3. Ed., 2007). Performance and precision characteristics of this protocol were evaluated in a collaborative study with participation of 14 laboratories from seven European countries. The laboratories performed qualitative, semi-quantitative and quantitative analyses on samples of chicken meat, cut lettuce, and milk artificially inoculated with different concentrations including blank duplicates of one strain of Campylobacter coli (SLV-271) and one strain of Campylobacter jejuni (SLV-542). Expected concentrations (95% C.I.) (cfu g(-1) or ml(-1)) of both strains in matrices were 0.6-1.4 and 23-60 for qualitative detection, and 0.6-1.4; 23-60; and 420-1200 for semi-quantitative detection. For quantitative determination, the expected concentrations of C. jejuni/C. coli were 420-1200/580-1100; 2100-6000/6300-11,000; and 4100-11,000/53,000-97,000 cfu g(-1) or ml(-1). The qualitative and semi-quantitative techniques resulted in comparable detection. The overall specificity and sensitivity of the detection techniques was 98.6% (95% C.I.: 95.1-99.8%) and 82.8% (C.I.: 78.4-86.6%), respectively. The sensitivity was not influenced by food matrix (P=0.359), but was significantly lower for C. coli compared to C. jejuni (P=0.007) and for concentrations below 1.4 cfu g(-1) (P0.001). The detection techniques were therefore only considered satisfactory for detection of Campylobacter concentrations above approximately 25 cfu g(-1) for all matrices tested, which was supported by calculation of values for accordance, concordance, and concordance odds ratio. No statistical difference was found between enumerations obtained by the semi-quantitative and quantitative techniques for comparable concentrations of Campylobacter (420-1200 cfu g(-1) or cfu ml(-1)) (P=0.104). Both techniques underestimated concentrations of thermotolerant Campylobacter in milk. The semi-quantitative technique estimated low inoculation levels of Campylobacter more correctly than the high inoculation levels. Counts obtained on the two selective plating media, Abeyta-Hunt-Bark agar added to it 0.1% triphenyl tetrazolium chloride and modified charcoal cephoperazone desoxycholate agar were not significantly different (P=0.143). Expressed as an absolute difference between log(10)-transformed results, the overall values for repeatability (r) and reproducibility (R) were r=log(10) 0.43 and R=log(10) 1.99, respectively. By omitting results from laboratories with high level of variability in results, R was reduced to log(10) 1.88. We suggest that the poor detection of low numbers, the underestimation in milk samples, and the large variation between laboratories can be explained by the general difficulties in handling Campylobacter. In conclusion, NMKL 119, 3. Ed., 2007, is regarded as an acceptable protocol for detection of thermotolerant Campylobacter at concentrations above 25 cfu g(-1) and also for enumeration of thermotolerant Campylobacter in chicken meat.

Raw meat for sausage production can be contaminated with Salmonella. For technical reasons, meat is often frozen prior to mincing but it is unknown how growth of Salmonella in meat prior to freezing affects its growth potential during sausage fermentation. We investigated survival of exponential- and stationary-phase Salmonella Typhimurium (DT12 and DTU292) during freezing at -18°C and their subsequent growth potential during 72h sausage fermentation at 25°C. After 0, 7 and >35d of frozen storage, sausage batters were prepared with NaCl (3%) and NaNO2 (0, 100ppm) and fermented with and without starter culture. With no starter culture, both strains grew in both growth phases. In general, a functional starter culture abolished S. Typhimurium growth independent of growth phase and we concluded that ensuring correct fermentation is important for sausage safety. However, despite efficient fermentation, sporadic growth of exponential-phase cells of S. Typhimurium was observed drawing attention to the handling and storage of sausage meat.

Clostridium perfringens 790-94 and 44071.C05 carrying a chromosomal and a plasmid cpe gene, respectively, were used to determine differences in heat resistance and growth characteristics between the genotypes. Heat inactivation experiments were conducted using an immersed coil apparatus. Spore germination, outgrowth, and lag phase, together named GOL time, as well as generation times were determined during constant temperatures in fluid thioglycollate (FTG) medium as well as in vacuum-packed, heat-treated minced turkey. GOL time and growth were also monitored during cooling scenarios from 65 to 10 degrees C for 3, 4, 5, 6, and 7 h in vacuum-packed, heat-treated minced turkey. Spores of strain 790-94 were approximately 10-fold more heat resistant at 85 degrees C than those of strain 44071.C05, and strain 790-94 also had a higher temperature growth range in FTG. The higher growth range for a chromosomal enterotoxin-producing CPE+ strain was confirmed using two other strains carrying a chromosomal (NCTC8239) and plasmid (945P) cpe gene. Moreover, strain 790-94 had shorter GOL times at 50 degrees C in turkey and approximately half the generation time compared with strain 44071.C05 at temperatures > or = 45 degrees C in both FTG and turkey. Strain 790-94 increased with 0.3, 1.0, 1.7, and 2.0 logs, respectively, during cooling from 65 to 10 degrees C in 4, 5, 6, and 7 h, which was significantly higher than for strain 44071.C05. A maximum acceptable cooling time of 5 h between 65 and 10 degrees C is suggested.

Aims: To evaluate a quantifying image analysis method for assessing the degree of hand contamination and efficacy of hand washing procedures. Methods and Results: Two types of experimental design were used. In one, different concentrations of pure cultures of Escherichia coli, Listeria innocua and Pseudomonas flourescens were applied to hands. In the other, hands were contaminated by handling various raw foods. Imprints of the contaminated palms were made on 24·5 × 24·5 cm agar plates using appropriate agars. After incubation, digital photographs of the plates were analysed using image analysis. In pure culture studies with selective agars, levels from 1 to 106 CFU cm−2 palm could be monitored. For aerobic, mesophilic organisms from raw chicken, levels from 103 to 106 CFU cm−2 palm were correlated linearly to image analysis data. Conclusions: The image analysis of palm imprints made on agar plates was suitable for assessing the degree of contamination from foods on the palms. Sensitivity and specificity depended on the agar used and the type of contamination encountered. Significance and Impact of the Study: Data capture by the image analysis method is simple and can be partly automated. Sampling time is short for the person to be tested, which makes it an attractive method for assessing hand hygiene status in larger field trials.

Bacteriocin-producing starter cultures have been suggested as natural food preservatives; however, development of resistance in the target organism is a major concern. We investigated the development of resistance in Listeria monocytogenes to the two major bacteriocins pediocin PA-1 and nisin A, with a focus on the variations between strains and the influence of environmental conditions. While considerable strain-specific variations in the frequency of resistance development and associated fitness costs were observed, the influence of environmental stress seemed to be bacteriocin specific. Pediocin resistance frequencies were determined for 20 strains and were in most cases ca. 10 −6 . However, two strains with intermediate pediocin sensitivity had 100-fold-higher pediocin resistance frequencies. Nisin resistance frequencies (14 strains) were in the range of 10 −7 to 10 −2 . Strains with intermediate nisin sensitivity were among those with the highest frequencies. Environmental stress in the form of low temperature (10°C), reduced pH (5.5), or the presence of NaCl (6.5%) did not influence the frequency of pediocin resistance development; in contrast, the nisin resistance frequency was considerably reduced (−8 ). Pediocin resistance in all spontaneous mutants was very stable, but the stability of nisin resistance varied. Pediocin-resistant mutants had fitness costs in the form of reduction down to 44% of the maximum specific growth rate of the wild-type strain. Nisin-resistant mutants had fewer and less-pronounced growth rate reductions. The fitness costs were not increased upon applying environmental stress (5°C, 6.5% NaCl, or pH 5.5), indicating that the bacteriocin-resistant mutants were not more stress sensitive than the wild-type strains. In a saveloy-type meat model at 5°C, however, the growth differences seemed to be negligible. The applicational perspectives of the results are discussed.

A modular process risk model approach was used to assess health risks associated with Salmonella spp. after consumption of the Danish meatball product (frikadeller) produced with fresh pork in a catering unit. Meatball production and consumption were described as a series of processes (modules), starting from 1.3kg meat pieces through conversion to 70g meatballs, followed by a dose response model to assess the risk of illness from consumption of these meatballs. Changes in bacterial prevalence, concentration, and unit size were modelled within each module. The risk assessment was built using observational data and models that were specific for Salmonella spp. in meatballs produced in the catering sector. Danish meatballs are often pan-fried followed by baking in an oven before consumption, in order to reach the core temperature of 75°C recommended by the Danish Food Safety Authority. However, in practice this terminal heat treatment in the oven may be accidentally omitted. Eleven production scenarios were evaluated with the model, to test the impact of heat treatments and cooling rates at different room temperatures. The risk estimates revealed that a process comprising heat treatment of meatballs to core temperatures higher than 70°C, and subsequent holding at room temperatures lower than 20°C, for no longer than 3.5h, were very effective in Salmonella control. The current Danish Food Safety Authority recommendation of cooking to an internal temperature of 75°C is conservative, at least with respect to Salmonella risk. Survival and growth of Salmonella during cooling of meatballs not heat treated in oven had a significant impact on the risk estimates, and therefore, cooling should be considered a critical step during meatball processing.

The growth of Listeria monocytogenes 13-249 in vacuum-packed, minced beef was investigated as a function of degree of heat injury (including no injury i.e. uncooked beef), growth phase (logarithmic and late stationary phase), pH (5.6 and 6.2), and storage temperature (3, 10 and 20 degrees C) during a storage period of 30 days. Late logarithmic and late stationary phase cultures of L. monocytogenes 13-249 showed similar growth in refrigerated, vacuum-packed, raw minced beef with a high pH (6.2). In normal pH (5.6) beef there was no growth at 3 degrees C while growth at 10 and 20 degrees C was only observed for logarithmic phase cultures. Heat injured late stationary phase cultures with 95-99.9% injured cells in the surviving population (as measured by differential plating on enriched vs. selective media after sous vide cooking) did not grow or repair sublethal injuries in sous vide cooked beef at 3 degrees C while repair and growth took place at 10 as well as at 20 degrees C. In logarithmic phase cultures heat injury occurred very rapidly and > or = 99.9% heat injury was observed in all trials in spite of much lower pasteurization values and fewer log10 reductions compared with late stationary phase cultures. Regardless of growth phase, all cultures where a high degree of heat injury (> or = 99.9%) was observed, did not subsequently grow in the beef product at 3 or 10 degrees C within 30 days. Growth of heat injured cultures preexposed to heat shock (46 degrees C, 30 min) or slowly rising temperatures (0.3 degrees C min(-1)) before heat injury was also investigated. Heat shocked or heat adapted cultures generally responded in the same manner as non-stressed cultures (no growth at 3 degrees C) except that a longer lag phase was observed in beef processed at slowly rising temperatures and in normal pH beef at 10 degrees C. Although processing at slowly rising temperatures may slightly increase the survival of L. monocytogenes 13-249 in cooked beef, there seem to be no indication of an increase in subsequent growth potential of the surviving cells.

This paper illustrates a practical example of how quantitative aspects can be incorporated in the hazard analysis critical control point (HACCP) system. Using a commercial hot-fill production line as a case the likely microbial load in the end-product is quantified on the basis of the recipe of the product, microbiological specifications of ingredients, time/temperature profile of process and thermotolerance of hazards. It is also demonstrated how such estimates provide a link to the third step in HACCP, the specification of criteria for the critical control points. The results are validated in a storage test.

Oplever du af og til, at 3 timer ikke er nok til at nedkøle opvarmede retter fra 65°C til 10°C? Så er dette værktøj noget for dig. Værktøjet hjælper dig med at undersøge om din nedkøling er sikker. Værktøjet benytter sig af, at en nedkøling vil følge en eksponentiel kurve, når nedkølingsbetingelserne er konstante.

Har du behov for at opvarme mad ved lavere temperaturer end 75°C? Så er dette værktøj noget for dig. Værktøjet hjælper dig med at finde en sikker tid/temperatur kombination for en alternativ opvarmning. Værktøjet benytter sig af begrebet ækvivalente opvarmninger.

The anticaking agent potassium ferrocyanide, K 4 Fe(CN) 6 , was found to affect lipid oxidation in frozen, minced pork meat both in ‘normal’ concentrations, when added together with food grade salt to yield 2 % NaCl in the product, and in ‘unrealistic’ high concentrations added separately or together with analytical grade salt. The level of K 4 Fe(CN) 6 obtained from adding 2 % food grade salt accelerated the development of lipid hydroperoxides, but affected the development of TBARS to a lesser degree. High level of K 4 Fe(CN) 6 seems to protect hydroperoxides from degradation to secondary lipid oxidation products measured as TBARS. The use of salt with the anticaking agent, K 4 Fe(CN) 6 , in meat processing should be reconsidered for each product since it may enhance lipid oxidation. A mechanism for mediation by the Fe(CN) 6 4− Fe(CN) 6 3− redox couple of pigment-catalysed lipid oxidation is suggested, based on an observed correlation between oxymyoglobin oxidation (measured as tristimulus colorimetric parameter, a) and lipid oxidation (measured as TBARS) for the frozen pork patties.

Food chain information does not per se allow an effective distinction of herds according to shedding of Salmonella. Thus, no effective sorting of pigs at slaughter according to Salmonella risk is possible and hygiene improvement is the only effective mitigating tool so far at the slaughter. From a large study of 1906 slaughter pigs we quantified Salmonella and established quantitative hygiene data (E. coli) on pig carcasses (paired data) at slaughter. Based on the results, we found a positive correlation between level of E. coli and the prevalence of Salmonella positive carcasses. The odds ratio for Salmonella being present on the carcass was found to increase by 1.87 for every one log10 unit increase of E. coli found on the carcass. A simple Salmonella consumer risk model was constructed using the observed levels of E. coli contamination as input and the model, established a positive correlation between slaughter hygiene (E. coli) and consumer risk. Further, we analysed two years’ own control data on Salmonella (prevalence data) and E. coli (quantitative data) from four large slaughterhouses in Denmark and found a similar positive correlation between the E. coli level and the carcass prevalence of Salmonella. The aim of this study was to propose a principle for setting risk based hygiene targets on E. coli on carcasses at pig slaughter. As such we provide input to the discussion on how to develop a risk based meat control procedure, based on statistical process control. Introduction The Salmonella is widespread in the slaughter pig production in Europe, and Salmonella from pork constitutes a significant risk for consumers. In recent years the ability of the classical meat control to provide consumer protection against food borne pathogens, has been discussed. A consensus of basing the meat control on food chain information of the pathogens is emerging in Europe. Food chain information do however not per se allow for an effective distinction between pigs from Salmonella positive and negative herds, and improvement of the general slaughter hygiene is the only mitigating tool to use. A modernisation of the meat control could include a risk based statistical process control but so far there have been no reports describing how the hygiene level at slaughter associates to Salmonella risk. We have established quantitative hygiene data (E. coli) and quantified Salmonella on pig carcasses at from 2880 pigs slaughter. Moreover we have analysed two years own control data on E. coli and Salmonella from five large pig slaughter houses in in Denmark. The objective is to establish the correlation between the hygiene level and presence of Salmonella and to provide the first suggestion for a method to set risk based process hygiene criteria at pig slaughter. Material and methods Sample collection 1906 carcasses from pigs slaughtered at five large Danish pig slaughterhouses were sampled in the period May 2005 to June 2007. Carcass swabs (2800 cm2) from was taken just before cooling and analysed both quantitatively for E. coli and semi-quantitatively for Salmonella. A total of 75 ml peptone water was added to stomacher bags with carcass swabs containing approximately 12.5 ml of peptone water and tissue fluid. The sample was stomached and one millilitre of 10-fold dilutions were spread on Petrifilm and subsequently incubated at 41.5 °C for 23-25 h. The number of E. coli was determined using Select E. coli Count Plate Petrifilm (3M Microbiology, St. Paul, MN, USA) in accordance with the supplier’s instructions. Cell counts were determined by automated reading using a Petrifilm plate reader MI649 9 (3M Microbiology, St. Paul, MN, USA). From a the ten-fold dilution of the homogenate, a semi-quantitative analysis for Salmonella was performed. All stomached samples were analysed for Salmonella using MSRV agar (ISO 6579, Annex D, Anonymous, 2007). Own control data from the same five slaughter houses were obtained based on swabbing of 300 cm2 mandatory for slaughter-houses exporting to USA. Each day one pooled sample of five swab samples were analysed for Salmonella and one sample per 1000 carcasses were analysed for E. coli with a range of 5-12 samples per day depending of slaughterhouse.

OBJECTIVESous-vide cooking and molecular gastronomy has started a wave of experimenting with Low Temperature Long Time (LTLT) heat treatments. Heat treatments, at temperatures as low as 50°C, have been suggested by celebrity chefs. LTLT treatments often take hours to reach to the final core temperature and Cl. perfringens is, therefore, of special interest as it may outgrow during the coming up time and cause food safety problems. This study was undertaken to set up a predictive tool to establish the outgrowth potential of C. perfringens in LTLT meat products as a function of the applied heating profile.METHODSChallenge tests were performed at two dynamic temperature profiles (fast LTLT, 2.6 h from 10 to 53°C, and slow LTLT, 3.8 h from 10 to 53°C) with three types of inoculums (spores, heat-active spores and vegetative cells) of Cl. perfringens 790-94 in two different types of meat pork (pH 5.6) and chicken (pH adjusted to 6.8). Challenge tests representing LTLT treatments of beef were collected from the literature. The obtained growth data were used for evaluation of three different growth models originally validated for prediction of growth during cooling (Le Marc et al. 2008, Juneja et al. 2011, Jaloustre et al. 2011). The data in inactivation phase were used for evaluation of three inactivation models generated by Foegeding and Busta (1980), van Asselt and Zwietering (2006) and Jaloustre et al. (2012). Finally, a new growth model, derived from the model structure of Le Marc et al. (2008), was developed from literature data (215 isothermal growth data), and was combined with a linear inactivation model developed from data at 53°C from this study for completely predicting fate of Cl. perfringens during LTLT treatment. RESULTSVery short lag times were observed in most of the challenge tests, especially in high pH chicken. By using the acceptable prediction zone method, performance of literature models was evaluated and none of the growth and inactivation models could successfully predict the growth or inactivation of Cl. perfringens for the LTLT conditions of our challenge tests. Therefore, a new growth model and a new inactivation model were developed and combined to predict the overall fate of Cl. Perfringens during LTLT profiles at 53°C. However, predicted lag time was still much longer than the observed lag time in our challenge tests, which caused a general underestimation of growth giving rise to overestimation of inactivation in particular for chicken. To obtain more precise predictions, an RLT of 2-3 was recommended for chicken, independent on type of inoculums, and for vegetative cells in pork. For spores and heated spores in pork the increase of Cl. perfringens during LTLT coming up time never exceeded 1 log10-unit.CONCLUSIONS AND IMPACT OF THE STUDYA model combining both growth as well as inactivation for prediction of fate of Cl. perfringens during the LTLT treatment was developed. The model is the first predictive model specifically designed for LTLT treatment of meats. Very short lag times were observed during LTLT treatments, which were not observed in isothermal or cooling conditions previously. The reason for short lag time during slowly increasing temperature conditions, and how to predict it, should be interesting for future studies.

This study was undertaken to model and predict growth of Salmonella and the dominating natural microbiota, and their interaction in ground pork. Growth of Salmonella in sterile ground pork at constant temperatures between 4 °C and 38 °C was quantified and used for developing predictive models for lag time, max. specific growth rate and max. population density. Data from literature were used to develop growth models for the natural pork microbiota. Challenge tests at temperatures from 9.4 to 24.1 °C and with Salmonella inoculated in ground pork were used for evaluation of interaction models. The existing Jameson-effect and Lotka-Volterra species interaction models and a new expanded Jameson-effect model were evaluated. F-test indicated lack-of-fit for the classical Jameson-effect model at all of the tested temperatures and at 14.1-20.2 °C this was caused by continued growth of Salmonella after the natural microbiota had reached their max. population density. The new expanded Jameson-effect model and the Lotka-Volterra model performed better and appropriately described the continued but reduced growth of Salmonella after the natural microbiota had reached their max. population density. The expanded Jameson-effect model is a new and simple species interaction model, which performed as well as the more complex Lotka-Volterra model.

The pH of the human stomach is dynamic and changes over time, depending on the composition of the food ingested and a number of host-related factors such as age. To evaluate the number of bacteria surviving the gastric acid barrier, we have developed a simple gastric acid model, in which we mimicked the dynamic pH changes in the human stomach. In the present study, model gastric fluid was set up to imitate pH dynamics in the stomachs of young and elderly people after ingestion of a standard meal. To model a serious foodborne pathogen, we followed the survival of Salmonella enterica serotype Dublin, and found that the addition of proteins such as pepsin, ovalbumin, and blended turkey meat to the simple gastric acid model significantly delayed pathogen inactivation compared with the control, for which no proteins were added. In contrast, no delay in inactivation was observed in the presence of bovine serum albumin, indicating that protection could be protein specific. The simple gastric acid model was validated against a more laborious and complex fermenter model, and similar survival of Salmonella Dublin was observed in both models. Our gastric acid model allowed us to evaluate the influence of food components on survival of pathogens under gastric conditions, and the model could contribute to a broader understanding of the impact of specific food components on the inactivation of pathogens during gastric passage.

Water mobility and distribution in cream cheeses with variations in fat (4, 15, and 26%), added salt (0, 0.625, and 1.25%), and pH (4.2, 4.7, and 5.2) were studied using (1)H NMR relaxometry. The cheese samples were inoculated with a mixture of Listeria innocua, Escherichia coli O157 and Staphylococcus aureus, and partial least-squares regression revealed that (1)H T(2) relaxation decay data were able to explain a large part of the variation in the survival of E. coli O157 (64-83%). However, the predictions of L. innocua and S. aureus survival were strongly dependent on the fat/water content of the samples. Consequently, the present results indicate that NMR relaxometry is a promising technique for predicting the survival of these bacteria; however, the characteristics of the sample matrix are substantial.

A number of intervention strategies against Campylobacter -contaminated poultry focus on postslaughter reduction of the number of cells, emphasizing the need for rapid and reliable quantitative detection of only viable Campylobacter bacteria. We present a new and rapid quantitative approach to the enumeration of food-borne Campylobacter bacteria that combines real-time quantitative PCR (Q-PCR) with simple propidium monoazide (PMA) sample treatment. In less than 3 h, this method generates a signal from only viable and viable but nonculturable (VBNC) Campylobacter bacteria with an intact membrane. The method's performance was evaluated by assessing the contributions to variability by individual chicken carcass rinse matrices, species of Campylobacter , and differences in efficiency of DNA extraction with differing cell inputs. The method was compared with culture-based enumeration on 50 naturally infected chickens. The cell contents correlated with cycle threshold ( C T ) values ( R 2 = 0.993), with a quantification range of 1 × 10 2 to 1 × 10 7 CFU/ml. The correlation between the Campylobacter counts obtained by PMA-PCR and culture on naturally contaminated chickens was high ( R 2 = 0.844). The amplification efficiency of the Q-PCR method was not affected by the chicken rinse matrix or by the species of Campylobacter . No Q-PCR signals were obtained from artificially inoculated chicken rinse when PMA sample treatment was applied. In conclusion, this study presents a rapid tool for producing reliable quantitative data on viable Campylobacter bacteria in chicken carcass rinse. The proposed method does not detect DNA from dead Campylobacter bacteria but recognizes the infectious potential of the VBNC state and is thereby able to assess the effect of control strategies and provide trustworthy data for risk assessment.

Aims: This study elucidates the mechanisms by which a nonbacteriocinogenic Carnobacterium piscicola inhibits growth of Listeria monocytogenes. Methods and Results: Listeria monocytogenes was exposed to live cultures of a bacteriocin-negative variant of C. piscicola A9b in co-culture, in a diffusion chamber system, and to a cell-free supernatant. Suppression of maximum cell density (0–3·5 log units) of L. monocytogenes was proportional to initial levels of C. pisciola (103–107 CFU ml−1). Cell-to-cell contact was not required to cause inhibition. The cell-free C. piscicola supernatant caused a decrease in L. monocytogenes maximum cell density, which was abolished by glucose addition but not by amino acid, vitamin or mineral addition. The fermentate also gave rise to a longer lag phase and a reduction in growth rate. These effects were independent of glucose and may have been caused by acetate production by C. piscicola. 2D gel-electrophoretic patterns of L. monocytogenes exposed to C. piscicola or to L. monocytogenes fermentate did not differ. Treatment with C. piscicola fermentate resulted in down-regulation (twofold) of genes involved in purine- or pyrimidine metabolism, and up-regulation (twofold) of genes from the regulon for vitamin B12 biosynthesis and propanediol and ethanolamine utilization. Conclusions: A nonbacteriocinogenic C. piscicola reduced growth of L. monocytogenes partly by glucose depletion. Significance and Impact of the Study: Understanding the mechanism of microbial interaction enhances prediction of growth in mixed communities as well as use of bioprotective principles for food preservation.

Heating at slowly rising temperatures is suspected to enhance thermotolerance in Listeria monocytogenes and, since anaerobic environments have been shown to facilitate resuscitation of heat-injured cells of this micro-organism, concern may arise about the possibility of L. monocytogenes surviving in minimally preserved products. The effect of rapid ( > 10 degrees C min-1) and slow (0.3 and 0.6 degrees C min-1) heating on survival of L. monocytogenes in sous vide cooked beef was therefore examined at mild processing temperatures of 56 degrees, 60 degrees and 64 degrees C. No statistically significant difference (P = 0.70) was observed between the tested heating regimes. Since the average pH of beef was low (5.6), and little or no effect was observed, a pH-dependency of heat shock-induced thermotolerance in L. monocytogenes is suggested to account for this result.