Pretreatment of different food rest materials for bioconversion into fungal lipid-rich biomass.

Food rest materials have the potential to be used as media components in various types of fermentations. Oleaginous filamentous fungi can utilize those components and generate a high-value lipid-rich biomass, which could be further used for animal and human use. One of the main limitations in this process is the pretreatment of food rest materials, needed to provide homogenization, sterilization and solubilization. In this study, two pretreatment processes-steam explosion and enzymatic hydrolysis-were evaluated for potato and animal protein-rich food rest materials. The pretreated food rest materials were used for the production of fungal lipid-rich biomass in submerged fermentation by the oleaginous fungus Mucor circinelloides. Cultivation media based on malt extract broth and glucose were used as controls of growth and lipid production, respectively. It was observed that media based on food rest materials can support growth and lipid production in M. circinelloides to a similar extent as the control media. More specifically, the use of potato hydrolysate combined with chicken auto-hydrolysate resulted in a higher fungal total biomass weight than using malt extract broth. When the same C/N ratio was used for glucose and rest materials-based media, similar lipid content was obtained or even higher using the latter media.

Predicting the concentration of verotoxin-producing Escherichia coli bacteria during processing and storage of fermented raw-meat sausages.

A model to predict the population density of verotoxigenic Escherichia coli (VTEC) throughout the elaboration and storage of fermented raw-meat sausages (FRMS) was developed. Probabilistic and kinetic measurement data sets collected from publicly available resources were completed with new measurements when required and used to quantify the dependence of VTEC growth and inactivation on the temperature, pH, water activity (aw), and concentration of lactic acid. Predictions were compared with observations in VTEC-contaminated FRMS manufactured in a pilot plant. Slight differences in the reduction of VTEC were predicted according to the fermentation temperature, 24 or 34°C, with greater inactivation at the highest temperature. The greatest reduction was observed during storage at high temperatures. A population decrease greater than 6 decimal logarithmic units was observed after 66 days of storage at 25°C, while a reduction of only ca. 1 logarithmic unit was detected at 12°C. The performance of our model and other modeling approaches was evaluated throughout the processing of dry and semidry FRMS. The greatest inactivation of VTEC was predicted in dry FRMS with long drying periods, while the smallest reduction was predicted in semidry FMRS with short drying periods. The model is implemented in a computing tool, E. coli SafeFerment (EcSF), freely available from http://www.ifr.ac.uk/safety/EcoliSafeFerment. EcSF integrates growth, probability of growth, and thermal and nonthermal inactivation models to predict the VTEC concentration throughout FRMS manufacturing and storage under constant or fluctuating environmental conditions.

Cleaning of conveyor belt materials using ultrasound in a thin layer of water.

Cleaning of conveyor belts in the food industry is imperative for preventing the buildup of microorganisms that can contaminate food. New technologies for decreasing water and energy consumption of cleaning systems are desired. Ultrasound can be used for cleaning a wide range of materials. Most commonly, baths containing fairly large amounts of water are used. One possibility to reduce water consumption is to use ultrasonic cavitation in a thin water film on a flat surface, like a conveyor belt. In order to test this possibility, a model system was set up, consisting of an ultrasound transducer/probe with a 70-mm-diameter flat bottom, operating at 19.8 kHz, and contaminated conveyor belt materials in the form of coupons covered with a thin layer of water or water with detergent. Ultrasound was then applied on the water surface at different power levels (from 46 to 260 W), exposure times (10 and 20 s), and distances (2 to 20 mm). The model was used to test two different belt materials with various contamination types, such as biofilms formed by bacteria in carbohydrate- or protein-fat-based soils, dried microorganisms (bacteria, yeasts, and mold spores), and allergens. Ultrasound treatment increased the reduction of bacteria and yeast by 1 to 2 log CFU under the most favorable conditions compared with water or water-detergent controls. The effect was dependent on the type of belt material, the power applied, the exposure time, and the distance between the probe and the belt coupon. Generally, dried microorganisms were more easily removed than biofilms. The effect on mold spores was variable and appeared to be species and material dependent. Spiked allergens were also efficiently removed by using ultrasound. The results in this study pave the way for new cleaning designs for flat conveyor belts, with possibilities for savings of water, detergent, and energy consumption.

Effects of post-processing treatments on sensory quality and Shiga toxigenic Escherichia coli reductions in dry-fermented sausages.

The effects of post-processing treatments on sensory quality and reduction of Shiga toxigenic Escherichia coli (STEC) in three formulations of two types of dry-fermented sausage (DFS; salami and morr) were evaluated. Tested interventions provided only marginal changes in sensory preference and characteristics. Total STEC reductions in heat treated DFS (32°C, 6days or 43°C, 24h) were from 3.5 to >5.5 log from production start. Storing of sausages (20°C, 1month) gave >1 log additional STEC reduction. Freezing and thawing of sausages in combination with storage (4°C, 1month) gave an additional 0.7 to 3.0 log reduction in STEC. Overall >5.5 log STEC reductions were obtained after storage and freezing/thawing of DFS with increased levels of glucose and salt. This study suggests that combined formulation optimisation and post-process strategies should be applicable for implementation in DFS production to obtain DFS with enhanced microbial safety and high sensory acceptance and quality.

Heterogeneity in resistance to food-related stresses and biofilm formation ability among verocytotoxigenic Escherichia coli strains.

This study assessed the resistance of ten verocytotoxigenic Escherichia coli (VTEC) isolates of commonly encountered serogroups/-types and two non-pathogenic E. coli strains to various food-related stresses (acid, alkaline, heat and high hydrostatic pressure treatments) and their biofilm formation ability. In addition, the global changes in the cellular composition in response to the exposure to these adverse environments were monitored by Fourier Transform Infrared (FT-IR) spectroscopy for two of the strains. Large inter-strain variations in stress resistance were observed. The most tolerant strains belonged to serogroup O157 which included both the O157:H7 type strain EDL933 and a representative isolate of the sorbitol fermenting O157:H- VTEC clone (strain MF3582). Strain C-600, a non-pathogenic laboratory strain, was sensitive to multiple stresses. Although wide variation in biofilm-forming ability was observed among VTEC isolates, no consistent relationships between biofilm-forming ability and capacity to withstand stress exposures were found. Analysis of the allelic status of the rpoS gene, involved in the general stress response of stationary-phase cells, allowed detection of loss-of-function mutations for two strains, E218/02 and MF2411, both of them showing as common features a high sensitivity to alkaline and heat treatments and a poor ability to form mature biofilms. Evidences found in this study confirm rpoS as a highly mutable gene in nature, and suggest its relevance not only for the mount of an active stress response but also for the establishment of mature biofilm communities. Our findings contribute to increase the knowledge on the resistance of VTEC to environmental stresses commonly encountered in the food chain, which can lead to improved strategies for preventing VTEC infections.

Reduction of verotoxigenic Escherichia coli by process and recipe optimisation in dry-fermented sausages.

Outbreaks of verotoxigenic Escherichia coli (VTEC) linked to dry-fermented sausages (DFSs) have emphasized the need for DFS manufacturers to introduce measures to obtain enhanced safety and still maintain the sensory qualities of their products. To our knowledge no data have yet been reported on non-O157:H7 VTEC survival in DFS. Here, the importance of recipe and process variables on VTEC (O157:H7 and O103:H25) reductions in two types of DFS, morr and salami, was determined through three statistically designed experiments. Linear regression and ANOVA analyses showed that no single variable had a dominant effect on VTEC reductions. High levels of NaCl, NaNO(2), glucose (low pH) and fermentation temperature gave enhanced VTEC reduction, while high fat and large casing diameter (a(w)) gave the opposite effect. Interaction effects were small. The process and recipe variables showed similar effects in morr and salami. In general, recipes combining high batter levels of salt (NaCl and NaNO(2)) and glucose along with high fermentation temperature that gave DFS with low final pH and a(w), provided approximately 3 log(10) reductions compared to approximately 1.5 log(10) reductions obtained for standard recipe DFS. Storage at 4°C for 2months provided log(10) 0.33-0.95 additional VTEC reductions and were only marginally affected by recipe type. Sensory tests revealed only small differences between the various recipes of morr and salami. By optimisation of recipe and process parameters, it is possible to obtain increased microbial safety of DFS while maintaining the sensory qualities of the sausages.

Application of high pressure processing to reduce verotoxigenic E. coli in two types of dry-fermented sausage.

The effect of high pressure processing (HPP) on the survival of verotoxigenic Escherichia coli (VTEC) in two types of Norwegian type dry-fermented sausages was studied. Two different types of recipes for each sausage type were produced. The sausage batter was inoculated with 6.8 log(10) CFU/g of VTEC O103:H25. After fermentation, drying and maturation, slices of finished sausages were vacuum packed and subjected to two treatment regimes of HPP. One group was treated at 600 MPa for 10 min and another at three cycles of 600 MPa for 200 s per cycle. A generalized linear model split by recipe type showed that these two HPP treatments on standard recipe sausages reduced E. coli by 2.9 log(10) CFU/g and 3.3 log(10) CFU/g, respectively. In the recipe with higher levels of dextrose, sodium chloride and sodium nitrite E. coli reduction was 2.7 log(10) CFU/g in both treatments. The data show that HPP has a potential to make the sausages safer and also that the effect depends somewhat on recipe.

Reduction of verotoxigenic Escherichia coli by process and recipe optimisation in dry-fermented sausages.

Outbreaks of verotoxigenic Escherichia coli (VTEC) linked to dry-fermented sausages (DFSs) have emphasized the need for DFS manufacturers to introduce measures to obtain enhanced safety and still maintain the sensory qualities of their products. To our knowledge no data have yet been reported on non-O157:H7 VTEC survival in DFS. Here, the importance of recipe and process variables on VTEC (O157:H7 and O103:H25) reductions in two types of DFS, morr and salami, was determined through three statistically designed experiments. Linear regression and ANOVA analyses showed that no single variable had a dominant effect on VTEC reductions. High levels of NaCl, NaNO(2), glucose (low pH) and fermentation temperature gave enhanced VTEC reduction, while high fat and large casing diameter (a(w)) gave the opposite effect. Interaction effects were small. The process and recipe variables showed similar effects in morr and salami. In general, recipes combining high batter levels of salt (NaCl and NaNO(2)) and glucose along with high fermentation temperature that gave DFS with low final pH and a(w), provided approximately 3 log(10) reductions compared to approximately 1.5 log(10) reductions obtained for standard recipe DFS. Storage at 4 degrees C for 2 months provided log(10) 0.33-0.95 additional VTEC reductions and were only marginally affected by recipe type. Sensory tests revealed only small differences between the various recipes of morr and salami. By optimisation of recipe and process parameters, it is possible to obtain increased microbial safety of DFS while maintaining the sensory qualities of the sausages.

Effect of starter culture inoculation on feed hygiene and microbial population development in fermented pig feed composed of a cereal grain mix with wet wheat distillers' grain.

AIMS: Investigating the influence of an added starter culture on the properties of fermented liquid pig feed. METHODS AND RESULTS: Diets of cereal grain blended with wet wheat distillers' grain that were either not inoculated (WWDG), inoculated with a silage starter culture at start (WWDGsc1) or at start and at each backslopping (replacement of 80% the content with fresh mixture, simulating feed outtake, WWDGsc5) were fermented for 5 days, followed by 5 days of daily backslopping. Numbers of undesirable micro-organisms (enterobacteria, moulds) were reduced in all fermentations; particularly enterobacteria in the starter culture inoculated diets. Lactobacillus plantarum present in the starter culture became dominant in diets WWDGsc1 and WWDGsc5. However, Lactobacillus panis that was dominating WWDG was also abundant in WWDGsc1 and WWDGsc5. Yeast populations were not influenced by the starter culture, with Pichia fermentans dominating all fermentations. All diets had similar chemical characteristics with the exception of a significant increase of all tested organic acids in WWDGsc5. CONCLUSIONS: The addition of a starter culture influences the bacterial population in fermented liquid feed, but there is also a strong impact of the flora already present in the feed ingredients. The yeast population is not influenced by adding a lactic acid bacteria (LAB) starter culture. A consortium of LAB and yeast strains adapted to the fermentation should be used as starter culture. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that it is possible to influence the current unpredictable and spontaneous process of feed fermentation when appropriate starter cultures are used. For this purpose, LAB and yeasts with desirable characteristics should be isolated.

Secreted enteric antimicrobial activity localises to the mucus surface layer.

OBJECTIVES: The intestinal mucosa is constantly exposed to a dense and highly dynamic microbial flora and challenged by a variety of enteropathogenic bacteria. Antibacterial protection is provided in part by Paneth cell-derived antibacterial peptides such as the alpha-defensins. The mechanism of peptide-mediated antibacterial control and its functional importance for gut homeostasis has recently been appreciated in patients with Crohn's ileitis. In the present study, the spatial distribution of antimicrobial peptides was analysed within the small intestinal anatomical compartments such as the intestinal crypts, the overlaying mucus and the luminal content. METHODS: Preparations from the different intestinal locations as well as whole mouse small intestine were extracted and separated by reversed-phase high-performance liquid chromatography. Antibacterial activity was determined in extracts, and the presence of antimicrobial peptides/proteins was confirmed by N-terminal sequencing, mass spectrometry analysis and immunodetection. RESULTS: The secreted antibacterial activity was largely confined to the layer of mucus, whereas only minute amounts of activity were noted in the luminal content. The extractable activity originating from either crypt/mucus/lumen compartments respectively (given as a percentage) was for Listeria monocytogenes, 48 (4)/44 (4)/8 (8); Enterococcus faecalis, 44 (10)/49 (3)/7 (7); Bacterium megaterium, 56 (4)/42 (3)/2 (1); Streptococcus pyogenes, 48 (4)/46 (3)/6 (6); Escherichia coli, 46 (4)/47 (3)/7 (7); and Salmonella enterica sv. Typhimurium, 38 (3)/43 (7)/19 (10). A spectrum of antimicrobial peptides was identified in isolated mucus, which exhibited strong and contact-dependent antibacterial activity against both commensal and pathogenic bacteria. CONCLUSION: These findings show that secreted antimicrobial peptides are retained by the surface-overlaying mucus and thereby provide a combined physical and antibacterial barrier to prevent bacterial attachment and invasion. This distribution facilitates high local peptide concentration on vulnerable mucosal surfaces, while still allowing the presence of an enteric microbiota.

Heterologous protein secretion by Lactobacillus plantarum using homologous signal peptides.

AIMS: To test seven selected putative signal peptides from Lactobacillus plantarum WCFS1 in terms of their ability to drive secretion of two model proteins in Lact. plantarum, and to compare the functionality of these signal peptides with that of well-known heterologous signal peptides (Usp45, M6). METHODS AND RESULTS: Signal peptide functionality was assessed using a series of modular derivatives of the pSIP vectors for peptide pheromone-controlled high-level gene expression in lactobacilli. Several of the constructs with homologous signal peptides yielded similar or higher reporter protein activities than constructs with heterologous signal peptides. Two of the homologous signal peptides (Lp_0373 and Lp_0600) appeared as especially promising candidates for directing secretion, as they were among the best performing with both reporter proteins. CONCLUSIONS: We have identified homologous signal peptides for high-level secretion of heterologous proteins in Lact. plantarum. With the model proteins, some of these performed better than commonly used heterologous signal peptides. SIGNIFICANCE AND IMPACT OF THE STUDY: The homologous signal peptides tested out, in this study, could be useful in food-grade systems for secretion of interesting proteins in Lact. plantarum. The constructed modular secretion vectors are easily accessible for rapid signal peptide screening.

Alteration in human defensin-5 expression following gastric bypass surgery.

BACKGROUND: Roux-en-Y gastric bypass surgery provides a novel human model to investigate small bowel mucosal innate immunity, in which there is loss of gastric acid-mediated protection against orally-acquired microorganisms. AIM: To study changes in jejunal mucosal immunoreactivity of human defensin (HD)-5, an antimicrobial peptide normally produced by Paneth cells. METHODS: Mucosal samples were obtained from 18 female patients (24-54 years), from the same segment of jejunum during and after gastric bypass surgery. Samples were used for bacterial culture and immunohistochemistry using anti-HD-5 antibody. The number of immunoreactive cells per crypt and villus were determined and expressed as mean (SD). RESULTS: No bacteria were cultured from any of the perioperative jejunal samples but colonies of bacteria normally present in the pharynx were identified during culture of all postoperative jejunal biopsy specimens (1->100 colonies). Paneth cell numbers per crypt were unchanged after gastric bypass (4.16 (0.71) vs 4.24 (0.78)). However, following surgery, there was an increase in HD-5-positive intermediate cells per crypt (0.25 (0.41) vs 1.12 (0.66), p<0.01), HD-5 staining enterocytes per crypt (0.03 (0.09) vs 1.38 (1.10), p<0.01), HD-5 staining material in the crypt lumen (crypt lumens: 5.0% (10.9%) vs 68.1% (27.9%), p<0.01) and HD-5 immunoreactivity coating the luminal surface of villus enterocytes (villi sampled: 15.0% (31.0%) vs 67.5% (42.0%), p<0.01). CONCLUSIONS: Bacteria normally resident in the pharynx were present in the proximal jejunal mucosa following Roux-en-Y gastric bypass surgery. After gastric bypass, there was increased secretion of HD-5 and an increase in HD-5 expressing intermediate cells and enterocytes in the crypt. The increase in HD-5 expression in the jejunal mucosa following gastric bypass surgery is likely to be secondary to exposure to orally-acquired microorganisms.

Early changes in rectal nitric oxide and mucosal inflammatory mediators in Crohn's colitis in response to infliximab treatment.

BACKGROUND: Treatment with tumor necrosis factor-alpha monoclonal antibody (infliximab) reduces clinical activity and intestinal inflammation in Crohn's disease. AIM: To study the time-course of the effects of infliximab with reference to mucosal cytokine and inducible nitric oxide synthase expression. METHODS: Thirty-two patients with Crohn's disease were treated with single dose infliximab (5 mg/kg). Disease activity was assessed days 1, 3, 7 and 28 using Harvey-Bradshaw index. Rectal nitric oxide levels were determined and rectal biopsies collected before treatment, 1 h after infusion and on days 3, 7 and 28. Immunohistochemical staining against inducible nitric oxide synthase, tumor necrosis factor-alpha, interleukin-1beta and interferon-gamma were performed. RESULTS: Clinical response was seen in 14 patients with down-regulation of global immunohistochemistry expression, reaching nadir day 3. Rectal nitric oxide was increased at baseline (3578 +/- 1199 parts per billion, ppb) compared with controls (89 +/- 13 ppb) (P < 0.001). In patients with clinical response, rectal nitric oxide decreased from 3926 +/- 1687 ppb to 1050 +/- 428 ppb day 28 (P < 0.05). CONCLUSIONS: Down-regulation of mucosal inflammatory mediators occurs after infliximab. Rectal nitric oxide levels parallel down-regulation of inducible nitric oxide synthase, tumor necrosis factor-alpha, interleukin-1beta and interferon-gamma and may serve as a quantitative biomarker of intestinal inflammation.

High-level gene expression in Lactobacillus plantarum using a pheromone-regulated bacteriocin promoter.

AIMS: To use promoters and regulatory genes involved in the production of the bacteriocin sakacin P to obtain high-level regulated gene expression in Lactobacillus plantarum. METHODS AND RESULTS: In a plasmid containing all three operons naturally involved in sakacin P production, the genes encoding sakacin P and its immunity protein were replaced by the aminopeptidase N gene from Lactococcus lactis (pepN) or the beta-glucuronidase gene from Escherichia coli (gusA). The new genes were precisely fused to the start codon of the sakacin P gene and the stop codon of the immunity gene. This set-up permitted regulated (external pheromone controlled) overexpression of both reporter genes in L. plantarum NC8. For PepN, production levels amounted to as much as 40% of total cellular protein. CONCLUSIONS: Promoters and regulatory genes involved in production of sakacin P are suitable for establishing inducible high-level gene expression in L. plantarum. SIGNIFICANCE AND IMPACT OF THE STUDY: This study describes a system for controllable gene expression in lactobacilli, giving some of the highest expression levels reported so far in this genus.

Use of bacteriocin promoters for gene expression in Lactobacillus plantarum C11.

AIMS: To exploit promoters involved in production of the bacteriocin sakacin P for regulated overexpression of genes in Lactobacillus plantarum C11. METHODS AND RESULTS: Production of sakacin P by Lact. sakei LTH673 is controlled by a peptide-based quorum sensing system that drives strong, regulated promoters. One of these promoters (PorfX) was used to establish regulated overexpression of genes encoding chloramphenicol acetyltransferase from Bacillus pumilus, aminopeptidase N from Lactococcus lactis or chitinase B from Serratia marcescens in Lact. plantarum C11, a strain that naturally possesses the regulatory machinery that is necessary for promoter activation. The expression levels obtained were highly dependent on which gene was used and on how the promoter was coupled to this gene. The highest expression levels (14% of total cellular protein) were obtained with the aminopeptidase N gene translationally fused to the regulated promoter. CONCLUSIONS: Sakacin promoters permit regulated expression of a variety of genes in Lact. plantarum C11. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows the usefulness of regulated bacteriocin promoters for developing new gene expression systems for lactic acid bacteria, in particular lactobacilli.

Differences in susceptibility of Listeria monocytogenes strains to sakacin P, sakacin A, pediocin PA-1, and nisin.

Two hundred strains of Listeria monocytogenes collected from food and the food industry were analyzed for susceptibility to the class IIa bacteriocins sakacin P, sakacin A, and pediocin PA-1 and the class I bacteriocin nisin. The individual 50% inhibitory concentrations (IC(50)) were determined in a microtiter assay and expressed in nanograms per milliliter. The IC(50) of sakacin P ranged from 0.01 to 0.61 ng ml(-1). The corresponding values for pediocin PA-1, sakacin A, and nisin were 0.10 to 7.34, 0.16 to 44.2, and 2.2 to 781 ng ml(-1), respectively. The use of a large number of strains and the accuracy of the IC(50) determination revealed patterns not previously described, and for the first time it was shown that the IC(50) of sakacin P divided the L. monocytogenes strains into two distinct groups. Ten strains from each group were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins and amplified fragment length polymorphism. The results from these studies essentially confirmed the grouping based on the IC(50) of sakacin P. A high correlation was found between the IC(50) of sakacin P and that of pediocin PA-1 for the 200 strains. Surprisingly, the correlation between the IC(50) of the two class IIa bacteriocins sakacin A and sakacin P was lower than the correlation between the IC(50) of sakacin A and the class I bacteriocin nisin.

Development of an inducible gene expression system for Lactobacillus sakei.

AIM: To develop an inducible gene expression system for Lactobacillus sakei, based on the regulatory system of sakacin A production. METHODS AND RESULTS: A Lactobacillus/Escherichia coli shuttle vector; pKRV3, was constructed including the signal transducing system genes of the bacteriocin sakacin A. The gusA gene fused to PsapA promoter, cloned in this vector allowed for inducible beta-glucuronidase expression in L. sakei and L. plantarum following the addition of the sakacin A inducing peptide. PsapA appeared to be a strong and tightly controlled promoter when compared with known promoters. CONCLUSION: The pKRV3 system can be used as an inducible gene expression system in lactobacilli. SIGNIFICANCE AND IMPACT OF THE STUDY: A novel, inducible gene expression system has been developed for lactic acid bacteria relevant in food fermentations.

Inhibition of Listeria monocytogenes in chicken cold cuts by addition of sakacin P and sakacin P-producing Lactobacillus sakei.

AIMS: To evaluate the potential of sakacin P and sakacin P-producing Lactobacillus sakei for the inhibition of growth of Listeria monocytogenes in chicken cold cuts, by answering the following questions. (i) Is sakacin P actually produced in food? (ii) Is sakacin P produced in situ responsible for the inhibiting effect? (iii) How stable is sakacin P in food? METHODS AND RESULTS: Listeria monocytogenes, a Lact. sakei strain and/or the bacteriocin sakacin P were added to chicken cold cuts, vacuum packed and incubated at 4 or 10 degrees C for 4 weeks. Each of two isogenic Lact. sakei strains, one producing sakacin P and the other not, had an inhibiting effect on the growth of L. monocytogenes. The effect of these two isogenic strains on the growth of L. monocytogenes was indistinguishable, even though sakacin P was produced in the product by one of the two Lact. sakei strains. The addition of purified sakacin P had an inhibiting effect on the growth of L. monocytogenes. A high dosage of sakacin P (3.5 microg x g(-1)) had a bacteriostatic effect throughout the storage period of 4 weeks, while a low dosage (12 ng x g(-1)) permitted initial growth, but at a slow rate. After 4 weeks of storage, the number of L. monocytogenes in the samples with a low dosage of sakacin P was 2 logs below that in the untreated control. When using a high dosage of sakacin P, the bacteriocin was detected in samples stored for up to 6 weeks. CONCLUSIONS: (i) Sakacin P is produced by a Lact. sakei strain when growing on vacuum-packed chicken cold cuts. (ii) Inhibiting effects of Lact. sakei, other than sakacin P, are active in inhibiting the growth of L. monocytogenes growing on chicken cold cuts. (iii) Sakacin P is stable on chicken cold cuts over a period of 4 weeks. SIGNIFICANCE AND IMPACT OF THE STUDY: Both sakacin P and Lact. sakei were found to have potential for use in the control of L. monocytogenes in chicken cold cuts.

Evidence for a new low-lying resonance state in 7He.

Low-lying resonance states in 7He(6He+n), formed after fragmentation reactions of a 227 MeV/nucleon 8He beam on a carbon target, have been studied. Coincidences between 6He nuclei and neutrons, corresponding to the one-neutron knockout channel in 8He, were selected. The relative energy spectrum in the 6He+n system shows a structure, which is interpreted as the 7He ( Ipi = 3/2(-)) ground state, unbound with 0.43(2) MeV relative to the 6He+n system and a width of Gamma = 0.15(8) MeV overlapping with an excited ( Ipi = 1/2(-)) state observed at 1.0(1) MeV with a width of Gamma = 0.75(8) MeV.

The concept of effectiveness--a blind alley? A study of different interpretations in a Swedish county council.

Swedish health care organizations are experiencing pressure to make ever greater efforts to rationalize and to increase effectiveness in the way they plan and provide services. In order to gain a better understanding of the current practice of the three groups of key actors in Swedish health care--politicians, senior civil servants and operational managers--and their perception of effectiveness, a study was carried out in a Swedish county council using both qualitative and quantitative methods. While in general the concept of effectiveness is thought of as crucial, it is not clearly or uniformly defined within the organization. Each of the three groups defines the concept in a way that reflects their own function, which may lead efforts to achieve effectiveness into a blind alley.