Publications by authors named "Carsten Krischek"

26 Publications

  • Page 1 of 1

Effects of freezing temperatures and storage times on the quality and safety of raw turkey meat and sausage products.

Poult Sci 2021 Sep 11;100(9):101305. Epub 2021 Jun 11.

Foundation University of Veterinary Medicine Hannover, Institute for Food Quality and Food Safety, 30173 Hannover, Germany. Electronic address:

In this study, the effect of frozen storage of turkey meat on the processing properties into raw sausages was investigated. For this purpose, meat from the Musculus pectoralis of male turkeys was frozen in 3 independent runs for 12 and 24 wk at -18°C and -80°C. After thawing, the meat was examined physicochemically and microbiologically and processed into raw sausages. The sausages were examined on d 0, 7, 14, 21, and 28 of storage. The parameters L*, a*, b*, pH-value and a-value did not show any relevant significances between the experimental groups. The analysis of TBARS of the sausages made from frozen meat showed significantly higher values on d 14 and 28 compared to the unfrozen control group. Frozen storage also reduced the growth of Pseudomonas spp. and Enterobacteriaceae.
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http://dx.doi.org/10.1016/j.psj.2021.101305DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8313846PMC
September 2021

Impact of a Combination of UV-C Irradiation and Peracetic Acid Spray Treatment on and Contaminated Pork.

Foods 2021 Jan 20;10(2). Epub 2021 Jan 20.

Institute of Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany.

Efficient ways of decontamination are needed to minimize the risk of infections with , which causes gastrointestinal diseases in humans, and to reduce the numbers of to extend the shelf-life of meat. While many studies have focused on a single treatment of peracetic acid (PAA) or UV-C-irradiation, there are no studies about a combined treatment on meat. Therefore, in the present study, pork was inoculated with either or , and was treated with a combination of 2040 mJ/cm UV-C irradiation followed by a 2000 ppm PAA spray treatment (30 s). Samples were packed under modified atmosphere and stored for 1, 7, or 14 days. The samples were examined for and content, chemical and sensory effects, and meat quality parameters. For , a significant reduction of up to 2.16 log cfu/cm meat and for , up to 2.37 log cfu/cm meat was seen on day 14 after UV-C/PAA treatment compared to the untreated controls.
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http://dx.doi.org/10.3390/foods10020204DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7909388PMC
January 2021

Effects of duration and temperature of frozen storage on the quality and food safety characteristics of pork after thawing and after storage under modified atmosphere.

Meat Sci 2021 Apr 28;174:108419. Epub 2020 Dec 28.

Foundation University of Veterinary Medicine Hannover, Institute of Food Quality and Food Safety, Bischofsholer Damm 15, 30173 Hannover, Germany. Electronic address:

The aim of this study was to investigate the influence of the duration of frozen storage (12 and 24 weeks) and the storage temperature (-18 °C or - 80 °C) on the shelf life of pork in MAP for up to 14 days after thawing. Frozen meat was compared to unfrozen meat in different physicochemical and microbiological parameters. The parameters a*, b*, pH value, cooking loss, shear force and antioxidant activity showed no significant changes depending on the freezing process. The total moisture loss was significantly higher for frozen/thawed pork compared to unfrozen pork. The storage loss of all frozen samples showed higher values than the unfrozen samples on all examination days. The level of TBARS reached comparable values for all experimental groups. On examination days 7 and 14, significantly lower values of total plate count (TPC) and Pseudomonas spp. were measured for frozen pork compared to unfrozen pork. The temperature of frozen storage had no significant influence on the quality of pork.
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http://dx.doi.org/10.1016/j.meatsci.2020.108419DOI Listing
April 2021

Ostarine and Ligandrol Improve Muscle Tissue in an Ovariectomized Rat Model.

Front Endocrinol (Lausanne) 2020 17;11:556581. Epub 2020 Sep 17.

Department of Trauma Surgery, Orthopaedics and Plastic Surgery, University of Göttingen, Göttingen, Germany.

In postmenopausal women, hormonal decline changes muscle function and structure. The non-steroidal selective androgen receptor modulators (SARMs) Ostarine (OS) and Ligandrol (LG) have been shown to increase muscle mass and physical function while showing a relative low risk profile. Information about their effects on muscle structure and metabolism is lacking. To analyze this, two experiments were performed using ovariectomized rats as a standard model for postmenopausal conditions. In each experiment, 3-month old Sprague-Dawley rats were divided into five groups ( = 12 to 15). One group remained intact (Non-OVX), the other four groups were ovariectomized (OVX) and remained untreated for eight (OS Experiment) or nine (LG Experiment) weeks. Thereafter, rats of three of the four OVX groups were treated with OS or LG (with doses of 0.04, 0.4, or 4 mg/kg body weight/day) for 5 weeks. Then, uterus, gastrocnemius, and soleus muscles were weighed, fiber size, capillary density, and enzyme activity (lactate dehydrogenase [LDH], citrate synthase [CS], and complex I) were analyzed. In the LG experiment, intramuscular fat content was determined in the quadriceps femoris muscle. All OS treatments resulted in a higher capillary density in the gastrocnemius and longissimus muscles compared with the Non-OVX and the OVX rats, whereas all LG treatments showed a higher capillary density compared with the Non-OVX group. Muscle fiber size and distribution patterns were not changed under either SARM. The CS activity was higher in the longissimus muscle under OS treatment. LG resulted in a higher activity of CS in the gastrocnemius and of LDH in the longissimus muscle. Both SARMs showed an uterotrophic effect, OS at 4 and 0,4 mg dosages, LG at 4 mg dosage. In sum, beneficial effect on muscle vascularization was observed for both SARMs with a stronger impact for OS. LG showed more effect on muscle metabolism. However, a higher muscle weight and intramuscular fat content observed after LG treatment (4 mg) as well as an uterotrophic effect of both SARMs at higher dosages could be considered as an unfavorable side effects and might be a limitation for their application at these dosages.
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http://dx.doi.org/10.3389/fendo.2020.556581DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7528560PMC
May 2021

UV-C Irradiation of Rolled Fillets of Ham Inoculated with and .

Foods 2020 May 1;9(5). Epub 2020 May 1.

Institute for Food Quality and Food Safety, Foundation University of Veterinary Medicine Hannover, Bischofsholer Damm 15, 30173 Hannover, Germany.

Bacteria on ready-to-eat meat may cause diseases and lead to faster deterioration of the product. In this study, ready-to-eat sliced ham samples were inoculated with or and treated with ultraviolet (UV) light. The initial effect of a UV-C irradiation was investigated with doses of 408, 2040, 4080, and 6120 mJ/cm and the effect after 0, 7, and 14 days of refrigerated storage with doses of 408 and 4080 mJ/cm. Furthermore, inoculated ham samples were stored under light and dark conditions after the UV-C treatment to investigate the effect of photoreactivation. To assess the ham quality the parameters color and antioxidant capacity were analyzed during storage. UV-C light reduced and counts by up to 1.11 log and 0.79 log colony forming units/g, respectively, during storage. No photoreactivation of the bacteria was observed. Furthermore, significantly lower a* and higher b* values after 7 and 14 days of storage and a significantly higher antioxidant capacity on day 0 after treatment with 4080 mJ/cm were detected. However, there were no other significant differences between treated and untreated samples. Hence, a UV-C treatment can reduce microbial surface contamination of ready-to-eat sliced ham without causing considerable quality changes.
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http://dx.doi.org/10.3390/foods9050552DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7278610PMC
May 2020

Inactivation of Yersinia enterocolitica and Brochothrix thermosphacta on pork by UV-C irradiation.

Meat Sci 2019 Dec 7;158:107909. Epub 2019 Aug 7.

Foundation University of Veterinary Medicine Hannover, Institute of Food Quality and Food Safety, Bischofsholer Damm 15, 30173 Hannover, Germany. Electronic address:

Ultraviolet (UV) irradiation has gained interest as a decontamination method for food for several years. This study investigated how UV-C affected the microbial load of pork, inoculated with Yersinia (Y.) enterocolitica and Brochothrix (B.) thermosphacta. The initial effect as well as the effect after 1, 7 and 14 days of storage were investigated. Additionally, the meat quality parameters color, pH value, myoglobin redox form percentages and antioxidant capacity were analyzed. During storage, the bacterial load on pork was significantly reduced up to 1.2 log using doses of 408 or 2040 mJ/cm. In contrast to this, in vitro experiments with bacterial suspensions showed that calculated UV doses of 16.16 and 19.30 mJ/cm resulted in a 3.0 log reduction of Y. enterocolitica and B. thermosphacta, respectively. The analyzed meat quality parameters were not influenced by UV-C treatment. Hence, UV-C light can reduce microbial surface contamination without negatively affecting meat quality.
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http://dx.doi.org/10.1016/j.meatsci.2019.107909DOI Listing
December 2019

Peracetic acid reduces Campylobacter spp. on turkey skin: Effects of a spray treatment on microbial load, sensory and meat quality during storage.

PLoS One 2019 24;14(7):e0220296. Epub 2019 Jul 24.

Institute of Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.

Handling and consumption of Campylobacter-contaminated poultry meat is the most common cause of human campylobacteriosis. While many studies deal with interventions to reduce Campylobacter spp. on chicken carcasses, studies on other poultry species are rare. In the present study, a spray treatment with peracetic acid (PAA) on turkey carcasses was evaluated. For this, parts of breast fillets with skin and Campylobacter (C.) jejuni DSM 4688 (108 cfu/ml) inoculated drumsticks were sprayed for 30 s with PAA (1200 ppm) or water as control solution. Samples were packaged under modified atmosphere and stored at 4°C until analysis on day 1, 6 and 12. The breast fillets were used for determination of the total viable count, sensory and meat quality examination as well as myoglobin content and biogenic amines. The drumsticks were used for C. jejuni counts. PAA had a significant effect in reducing total viable counts on all days by up to 1.2 log10 compared to the untreated control. Treatment with water alone showed no effect. C. jejuni counts were significantly reduced by PAA (0.9-1.3 log10), while water achieved a 0.5 log10 reduction on C. jejuni counts on day 1. No differences in sensory, pH, electrical conductivity and myoglobin content could be found. The skin of the PAA treated fillets had lower redness values than the water control on day 1, whereas on day 12 parts of the water treated muscles were lighter than the untreated control. A lower putrescine content of the water sprayed fillets in comparison to the control sample on day 12 was the only significant difference concerning the biogenic amines. Results from this study indicate that a spray treatment with 1200 ppm PAA would be a useful measure to lower the Campylobacter spp. counts on turkey carcasses without having a negative influence on product quality.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0220296PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6656417PMC
March 2020

Peracetic acid reduces Campylobacter spp. numbers and total viable counts on broiler breast muscle and drumstick skins during modified atmosphere package storage.

Poult Sci 2019 Oct;98(10):5064-5073

Institute of Food Quality and Food Safety, Foundation University of Veterinary Medicine, Hannover, 30173 Hannover, Germany.

Constant high case numbers of human campylobacteriosis over the last few years show the necessity of efficient strategies to reduce the number of diseases. The aim of this study was to assess the effectiveness of peracetic acid (PAA) as spray application to reduce Campylobacter spp. on chicken meat. For this, the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of 25 Campylobacter jejuni and C. coli isolates were determined. All tested isolates had MICs ranging between 2 to 8 ppm PAA, while MBCs were 1- to 4-fold higher than the MIC. An additional time-kill test, using strain C. jejuni DSM 4688, revealed that after an incubation time of 2 h in medium, supplemented with 1-fold the MIC (4 ppm) of PAA, no surviving C. jejuni cells were detectable. For evaluation of a spraying treatment, C. jejuni DSM 4688 (108 cfu/mL) inoculated chicken drumsticks and native skin-on breast fillets were treated for 30 s with PAA of 1,200 ppm concentration. Samples were packaged in modified atmosphere packages and stored at 4°C until further analysis. On day 1, 6, and 12, the fillets were used for microbial (total viable count), sensory, and physicochemical (color, pH, electrical conductivity) analysis and meat samples for myoglobin redox forms and antioxidant activity were taken. A significant reduction of the total viable counts was seen on day 6 and 12 in comparison to the water control and to the untreated fillets, respectively. Campylobacter jejuni counts on the drumsticks were significantly reduced by PAA application on day 6 and 12 in comparison to the water treatment. Except on day 12, where PAA-treated fillets showed a slightly higher percentage of oxymyoglobin, no significant differences could be found in the sensory and physicochemical measurements as well as in myoglobin and antioxidant activity. Spray application of 1,200 ppm PAA to Campylobacter-contaminated chicken samples led to a significant reduction up to 1.1 log10 of Campylobacter spp. counts without influencing chemical and sensory meat quality parameters.
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http://dx.doi.org/10.3382/ps/pez266DOI Listing
October 2019

Effect of ethyl-lauroyl-arginate hypochloride in combination with high hydrostatic pressure processing on the microbial load and physico-chemical characteristics of minced and portioned chicken breast meat.

Poult Sci 2019 Feb;98(2):966-976

Foundation University of Veterinary Medicine Hannover, Institute of Food Quality and Food Safety, 30173 Hannover, Germany.

Campylobacter is an important hazard responsible for many human gastroenteritis cases. As poultry meat is the main source of Campylobacter, many approaches to reduce the Campylobacter load in this meat have been published. In the present study minced and whole broiler breast meat samples were inoculated with Campylobacter (C.) jejuni and treated with different concentrations of the food additive ethyl-Nα-lauroyl-L-arginate hypochloride (LAE, 1,000/1,500 ppm (minced meat); 400/1,000 ppm (whole meat)), with high hydrostatic pressure (HPP, 100/ 200 MPa) or a combination of both preservation methods, followed by vacuum storage up to day 14 after treatment. Aim of the study was to analyze if effects of LAE and HPP alone and in combination on the C. jejuni concentrations and on different meat quality parameters could be found. Analysis of minimal inhibitory and minimal bactericidal concentrations (MIC, MBC) of LAE against 11 C. jejuni and five C. coli strains resulted in MIC/ MBC of 32 ppm for 12 and 64 ppm for four strains investigated. Only 1,500 ppm LAE in minced meat resulted in a significant reduction of the C. jejuni concentrations directly after treatment (day 1) and on day 7 compared to the untreated control samples. Treatment of whole breast meat with 400 and 1,000 ppm LAE resulted in significantly lower C. jejuni concentrations on days 1, 7, and 14 compared to control samples. However, HPP alone and in combination with LAE was not able to reach significant microbial reduction. Whereas LAE only slightly influenced the lightness (L*) results of the minced meat (day 1), HPP treatment with 200 MPa generally increased the L* and yellowness (b*) results of the minced and whole meat on day 1. During further storage, color results were inconsistent in minced and whole meat samples, as well as the myoglobin redox form percentages in the whole meat. In conclusion, a synergistic effect of LAE and HPP could not be proved using the chosen concentrations of LAE and pressure values.
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http://dx.doi.org/10.3382/ps/pey427DOI Listing
February 2019

Carcass Quality, Meat Quality and Sensory Properties of the Dual-Purpose Chicken Lohmann Dual.

Foods 2018 Sep 25;7(10). Epub 2018 Sep 25.

Institute of Food Quality and Food Safety, Foundation University of Veterinary Medicine, D-30173 Hannover, Germany.

Over 40 million day-old layer line cockerels are culled in Germany each year, due to economic reasons, leading to a recently instigated research focus on the potential of dual-purpose breeds as an alternative to conventional poultry husbandry, especially the practice of culling. This paper aims to explore and assess the dual-purpose chicken breed "Lohmann Dual" (LD) performance ( = 30) and sensory characteristics ( = 48). Carcass and meat quality traits are evaluated, and descriptive sensory analysis of breast muscles is conducted. To define the scope of characteristics, a market sample of "Ross" Line ( = 35) is adducted. LD carcasses are characterized by higher leg than breast yield; carcass, breast and leg weights are higher in Ross. LD meat has a lower pH, differs in color, has higher drip and thawing losses, but lower cooking loss. LD breast muscles are firmer as indicated by shear force measurements, which is confirmed through the sensory analysis. Appearance, odor and flavor differ between the lines. Overall, distinguishable differences are found between both breeds. Further research should focus on the marketing aspect of the dual-purpose line, as some characteristics could draw consumers to this product. Animal welfare and ethical concerns should further be considered when considering dual-purpose breeds as a feasible alternative to culling.
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http://dx.doi.org/10.3390/foods7100156DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6210674PMC
September 2018

miRNAs regulate acute transcriptional changes in broiler embryos in response to modification of incubation temperature.

Sci Rep 2018 07 27;8(1):11371. Epub 2018 Jul 27.

Leibniz Institute for Farm Animal Biology, Institute for Genome Biology, 18196, Dummerstorf, Germany.

MicroRNAs are post-transcriptional regulators that play critical roles in diverse biological processes. We hypothesize that miRNAs may be involved in regulating transcriptome responses to changes in embryonic incubation temperature in chickens affecting differentiation and proliferation processes during tissue development. Therefore, we conducted comparative transcriptome profiling of miRNAs to examine altered expression in breast and hind muscle of embryos and day 35 chickens experiencing high (38.8 °C), control (37.8 °C), or low (36.8 °C) embryonic incubation temperature during embryonic day (ED) 7-10 or ED10-13. The results revealed differential expression of miRNAs due to modification of embryonic incubation temperature in a muscle type-specific and a developmental stage-specific manner. The immediate effects of thermal change observed in embryos were substantial compared to the subtle long-term effects in chickens at day 35 post-hatch. Upregulation of miR-133 in breast muscle and downregulation of miR-199a-5p, miR-1915, and miR-638 in hind muscle post ED7-10 high-temperature treatment are functionally associated with myogenesis and body size. ED10-13 low-temperature treatment led to downregulation of let-7, miR-93, and miR-130c that are related to proliferation and differentiation. The results provide insight into the dynamics of miRNA expression at variable embryonic incubation temperatures during developmental processes and indicate a major regulatory role of miRNAs in acute responses to modified environmental conditions that affect remodelling of cells and tissues.
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http://dx.doi.org/10.1038/s41598-018-29316-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6063901PMC
July 2018

Susceptibility of Methicillin-Resistant and -Susceptible Staphylococcus aureus Isolates of Various Clonal Lineages from Germany to Eight Biocides.

Appl Environ Microbiol 2018 07 18;84(13). Epub 2018 Jun 18.

Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany

Few studies have been conducted on the susceptibility of bacteria to biocides. A total of 182 methicillin-resistant and -susceptible isolates collected from healthy or diseased humans and animals in Germany were included in the present study. Sixty-three isolates of animal origin and 119 human isolates were tested for their MICs to eight biocides or heavy metals by the broth microdilution method. The MIC and MIC values of human and animal isolates were equal or differed by not more than 1 dilution step, and statistical analysis revealed that differences between MICs of human and animal isolates were not significant. However, when taking into account the multilocus sequence type (MLST), a strong tendency ( = 0.054) to higher MICs of silver nitrate was detected for clonal complex 398 (CC398) isolates from humans compared to those from animals. Furthermore, a comparison of MIC values from isolates belonging to different clonal lineages revealed that important human lineages such as CC22 and CC5 exhibited significantly ( < 0.05) higher MICs for the biocides chlorhexidine, benzethonium chloride, and acriflavine than the main animal lineage sequence type 398 (ST398). Isolates with elevated MIC values were tested for the presence of biocide and heavy metal tolerance-mediating genes by PCR assays, and the following genes were detected: ( [no. of isolates containing the gene] = 44), ( = 36), ( = 35), ( = 22), ( = 5), ( = 3), ( = 2), ( = 1), and/or - ( = 1), ( = 2), and ( = 1). However, only for some compounds was a correlation between the presence of a biocide tolerance gene and the level of MIC values detected. Biocides play an essential role in controlling the growth of microorganisms and the dissemination of nosocomial pathogens. In this study, we determined the susceptibility of methicillin-resistant and -susceptible isolates from humans and animals to various biocides and heavy metal ions and analyzed differences in susceptibilities between important clonal lineages. In addition, the presence of biocide or heavy metal tolerance-mediating genes was investigated. We demonstrated that important human lineages such as CC22 and CC5 had significantly higher MIC values for chlorhexidine, benzethonium chloride, and acriflavine than the main farm animal lineage, ST398. In addition, it was shown that for some combinations of biocides and tolerance genes, significantly higher MICs were detected for carriers. These findings provide new insights into biocide and heavy metal tolerance.
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http://dx.doi.org/10.1128/AEM.00799-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6007098PMC
July 2018

Influence of modified atmosphere and vacuum packaging with and without nanosilver-coated films on different quality parameters of pork.

J Food Sci Technol 2017 Sep 8;54(10):3251-3259. Epub 2017 Aug 8.

Institute of Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany.

Pork is often marketed in packages with high oxygen atmosphere (MAP) or vacuum to improve shelf life and appearance. As silver ions have antibacterial effects, food contact films coated with silver might improve the shelf life of meat. In the present study, pork was wrapped in commercially available films, coated with nanosilver particles, and stored in the two packaging variants MAP and vacuum for 12 days. During storage, samples were analyzed on days 1 (before packaging), 4, 8 and 12 for microbiological contamination, meat quality (e.g., pH, color), and for the percentages of the myoglobin (Mb) redox forms. In addition, the effects of the film were examined after inoculation of the meat with high quantities of methicillin-resistant (MRSA) cells before vacuum storage for 8 days. MAP storage resulted in higher lightness (L*) values, lower liquid loss and higher Mb oxidation compared to vacuum. Microbiological spoilage was partly affected by the packaging variants with reducing effects of the MAP. The nanosilver-coating only affects the Mb redox form percentages of the pork cutlets and on day 4 the L* values, whereas microbiological parameters were not influenced. As the nanosilver coating had no influence on the total viable bacteria counts as well as spp., and MRSA counts, an advantage of the nanosilver coating on the shelf life could be excluded.
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http://dx.doi.org/10.1007/s13197-017-2768-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5602988PMC
September 2017

Comparative analysis of the susceptibility to biocides and heavy metals of extended-spectrum β-lactamase-producing Escherichia coli isolates of human and avian origin, Germany.

Diagn Microbiol Infect Dis 2017 May 8;88(1):88-92. Epub 2017 Feb 8.

Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany. Electronic address:

A total of 174 extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates collected from humans (n=140) and healthy broiler chickens (n = 34) was included in the study. The MIC values of alkyl diaminoethyl glycin hydrochloride, benzethonium chloride, benzalkonium chloride, chlorhexidine, acriflavine, copper sulfate, silver nitrate and zinc chloride were determined by the broth microdilution method. Significant differences in MIC distributions were found between human and avian isolates and between CTX-M-, SHV- and TEM-type ESBL E. coli for chlorhexidine, silver nitrate, zinc chloride and copper sulfate by statistical analysis. Isolates with reduced susceptibility were investigated for the presence and localization of tolerance-mediating genes by PCR analysis and Southern blotting. The genes emrE, mdfA, sugE(c), cueO, copA, zntA and zitB were commonly present in isolates with elevated MICs, while the genes qacE∆1, qacF, qacH, sugE(p), cusC and pcoA, were less prevalent. In several isolates, a plasmid localization of the genes qacE∆1, qacF, qacH and sugE(p) on large plasmids >20 kb was detected.
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http://dx.doi.org/10.1016/j.diagmicrobio.2017.01.023DOI Listing
May 2017

Transient Shifts of Incubation Temperature Reveal Immediate and Long-Term Transcriptional Response in Chicken Breast Muscle Underpinning Resilience and Phenotypic Plasticity.

PLoS One 2016 9;11(9):e0162485. Epub 2016 Sep 9.

Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, 18196, Dummerstorf, Germany.

Variations in egg incubation temperatures can have acute or long-term effects on gene transcription in avian species. Altered gene expression may, in turn, affect muscle traits in poultry and indirectly influence commercial production. To determine how changes in eggshell temperature affect gene expression, incubation temperatures were varied [36.8°C (low), 37.8°C (control), 38.8°C (high)] at specific time periods reflecting two stages of myogenesis [embryonic days (ED) 7-10 and 10-13]. Gene expression was compared between interventions and matching controls by microarrays in broiler breast muscle at ED10 or ED13 and post-hatch at day 35. Early (ED7-10) high incubation temperature (H10ΔC) resulted in 1370 differentially expressed genes (DEGs) in embryos. Ingenuity pathway analysis revealed temporary activation of cell maintenance, organismal development, and survival ability genes, but these effects were not maintained in adults. Late high incubation temperature (ED10-13) (H13ΔC) had slightly negative impacts on development of cellular components in embryos, but a cumulative effect was observed in adults, in which tissue development and nutrition metabolism were affected. Early low incubation temperature (L10ΔC) produced 368 DEGs, most of which were down-regulated and involved in differentiation and formation of muscle cells. In adults, this treatment down-regulated pathways of transcriptional processes, but up-regulated cell proliferation. Late low temperature incubation (L13ΔC) produced 795 DEGs in embryos, and activated organismal survival and post-transcriptional regulation pathways. In adults this treatment activated cellular and organ development, nutrition and small molecule activity, and survival rate, but deactivated size of body and muscle cells. Thermal interventions during incubation initiate immediate and delayed transcriptional responses that are specific for timing and direction of treatment. Interestingly, the transcriptional response to transiently decreased incubation temperature, which did not affect the phenotypes, prompts compensatory effects reflecting resilience. In contrast, higher incubation temperature triggers gene expression and has long-term effects on the phenotype. These mechanisms of considerable phenotypic plasticity contribute to the biodiversity and broaden the basis for managing poultry populations.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0162485PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5017601PMC
August 2017

Immediate and long-term transcriptional response of hind muscle tissue to transient variation of incubation temperature in broilers.

BMC Genomics 2016 05 4;17:323. Epub 2016 May 4.

Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, 18196, Dummerstorf, Germany.

Background: In oviparous species accidental variation of incubation temperatures may occur under natural conditions and mechanisms may have evolved by natural selection that facilitate coping with these stressors. However, under controlled artificial incubation modification of egg incubation temperature has been shown to have a wide-ranging impact on post-hatch development in several poultry species. Because developmental changes initiated in-ovo can affect poultry production, understanding the molecular routes and epigenetic alterations induced by incubation temperature differences may allow targeted modification of phenotypes.

Results: In order to identify molecular pathways responsive to variable incubation temperature, broiler eggs were incubated at a lower or higher temperature (36.8 °C, 38.8 °C) relative to control (37.8 °C) over two developmental intervals, embryonic days (E) 7-10 and 10-13. Global gene expression of M. gastrocnemius was assayed at E10, E13, and slaughter age [post-hatch day (D) 35] (6 groups; 3 time points; 8 animals each) by microarray analysis and treated samples were compared to controls within each time point. Transcript abundance differed for between 113 and 738 genes, depending on treatment group, compared to the respective control. In particular, higher incubation temperature during E7-10 immediately affected pathways involved in energy and lipid metabolism, cell signaling, and muscle development more so than did other conditions. But lower incubation temperature during E10-13 affected pathways related to cellular function and growth, and development of organ, tissue, and muscle as well as nutrient metabolism pathways at D35.

Conclusion: Shifts in incubation temperature provoke specific immediate and long-term transcriptional responses. Further, the transcriptional response to lower incubation temperature, which did not affect the phenotypes, mediates compensatory effects reflecting adaptability. In contrast, higher incubation temperature triggers gene expression and has long-term effects on the phenotype, reflecting considerable phenotypic plasticity.
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http://dx.doi.org/10.1186/s12864-016-2671-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4855815PMC
May 2016

Low temperature cooking of pork meat - Physicochemical and sensory aspects.

Meat Sci 2016 Aug 29;118:82-8. Epub 2016 Mar 29.

Institute of Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, D-30173 Hannover, Germany. Electronic address:

Low-temperature cooking is increasingly used in the food sector. This study compared three different low temperature heating methods and one conventional cooking procedure of pork meat in a combi steamer with special emphasis on sensory parameters. Low temperature, long time (LTLT) treatments over 20h at 53°C or 58°C (LTLT 53°C or 58°C) showed considerable effects on meat tenderization. Heating to a core temperature of 60°C (low temperature method=LT) at 60°C oven temperature resulted in less tender but clearly juicier meat. LTLT 53°C and LT were evaluated as being equally acceptable by the panelists. The tenderest meat (LTLT 58°C) was mainly rejected because of a crumbly and dry mouth feeling. Conventional heating to a core temperature of 80°C at 180°C oven temperature resulted in low eating quality due to high toughness and low juiciness.
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http://dx.doi.org/10.1016/j.meatsci.2016.03.026DOI Listing
August 2016

High pressure as an alternative processing step for ham production.

Meat Sci 2016 Aug 18;118:22-7. Epub 2016 Mar 18.

Institute of Food Quality and Food Safety, University of Veterinary Medicine Hannover, Bischofsholer Damm 15, D-30173 Hannover, Germany. Electronic address:

As high pressure processing (HPP) is becoming more and more important in the food industry, this study examined the application of HPP (500 and 600MPa) as a manufacturing step during simulated ham production. By replacing conventional heating with HPP steps, ham-like texture or color attributes could not be achieved. HPP products showed a less pale, less red appearance, softer texture and higher yields. However, a combination of mild temperature (53°C) and 500MPa resulted in parameters more comparable to cooked ham. We conclude that HPP can be used for novel food development, providing novel textures and colors. However, when it comes to ham production, a heating step seems to be unavoidable to obtain characteristic ham properties.
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http://dx.doi.org/10.1016/j.meatsci.2016.03.014DOI Listing
August 2016

Molecular changes in mitochondrial respiratory activity and metabolic enzyme activity in muscle of four pig breeds with distinct metabolic types.

J Bioenerg Biomembr 2016 Feb 13;48(1):55-65. Epub 2016 Jan 13.

Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, 18196, Dummerstorf, Germany.

Skeletal muscles are metabolically active and have market value in meat-producing farm animals. A better understanding of biological pathways affecting energy metabolism in skeletal muscle could advance the science of skeletal muscle. In this study, comparative pathway-focused gene expression profiling in conjunction with muscle fiber typing were analyzed in skeletal muscles from Duroc, Pietrain, and Duroc-Pietrain crossbred pigs. Each breed type displayed a distinct muscle fiber-type composition. Mitochondrial respiratory activity and glycolytic and oxidative enzyme activities were comparable among genotypes, except for significantly lower complex I activity in Pietrain pigs homozygous-positive for malignant hyperthermia syndrome. At the transcriptional level, lactate dehydrogenase B showed breed specificity, with significantly lower expression in Pietrain pigs homozygous-positive for malignant hyperthermia syndrome. A similar mRNA expression pattern was shown for several subunits of oxidative phosphorylation complexes, including complex I, complex II, complex IV, and ATP synthase. Significant correlations were observed between mRNA expression of genes in focused pathways and enzyme activities in a breed-dependent manner. Moreover, expression patterns of pathway-focused genes were well correlated with muscle fiber-type composition. These results stress the importance of regulation of transcriptional rate of genes related to oxidative and glycolytic pathways in the metabolic capacity of muscle fibers. Overall, the results further the breed-specific understanding of the molecular basis of metabolic enzyme activities, which directly impact meat quality.
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http://dx.doi.org/10.1007/s10863-015-9639-3DOI Listing
February 2016

Muscle Transcriptional Profile Based on Muscle Fiber, Mitochondrial Respiratory Activity, and Metabolic Enzymes.

Int J Biol Sci 2015 1;11(12):1348-62. Epub 2015 Nov 1.

1. Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, D-18196 Dummerstorf, Germany.

Skeletal muscle is a highly metabolically active tissue that both stores and consumes energy. Important biological pathways that affect energy metabolism and metabolic fiber type in muscle cells may be identified through transcriptomic profiling of the muscle, especially ante mortem. Here, gene expression was investigated in malignant hyperthermia syndrome (MHS)-negative Duroc and Pietrian (PiNN) pigs significantly differing for the muscle fiber types slow-twitch-oxidative fiber (STO) and fast-twitch-oxidative fiber (FTO) as well as mitochondrial activity (succinate-dependent state 3 respiration rate). Longissimus muscle samples were obtained 24 h before slaughter and profiled using cDNA microarrays. Differential gene expression between Duroc and PiNN muscle samples were associated with protein ubiquitination, stem cell pluripotency, amyloid processing, and 3-phosphoinositide biosynthesis and degradation pathways. In addition, weighted gene co-expression network analysis within both breeds identified several co-expression modules that were associated with the proportion of different fiber types, mitochondrial respiratory activity, and ATP metabolism. In particular, Duroc results revealed strong correlations between mitochondrion-associated co-expression modules and STO (r = 0.78), fast-twitch glycolytic fiber (r = -0.98), complex I (r=0.72) and COX activity (r = 0.86). Other pathways in the protein-kinase-activity enriched module were positively correlated with STO (r=0.93), while negatively correlated with FTO (r = -0.72). In contrast to PiNN, co-expression modules enriched in macromolecule catabolic process, actin cytoskeleton, and transcription activator activity were associated with fiber types, mitochondrial respiratory activity, and metabolic enzyme activities. Our results highlight the importance of mitochondria for the oxidative capacity of porcine muscle and for breed-dependent molecular pathways in muscle cell fibers.
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http://dx.doi.org/10.7150/ijbs.13132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4671993PMC
October 2016

Altered incubation temperatures between embryonic Days 7 and 13 influence the weights and the mitochondrial respiratory and enzyme activities in breast and leg muscles of broiler embryos.

Mol Reprod Dev 2016 Jan 14;83(1):71-8. Epub 2015 Dec 14.

Department of Animal Sciences, Quality of Food of Animal Origin, Georg-August-University Goettingen, Albrecht-Thaer Weg, Goettingen, Germany.

Altering incubation temperature during embryogenesis has an impact on chicken embryo growth, but the underlying molecular mechanisms are not understood; the present study was performed to address these changes. Broiler eggs were incubated at low (36.8°C), control (37.8°C), and high (38.8°C) temperatures between Embryonic Day (ED) 7 and 10 or ED 10 and 13, which cover critical periods of embryonic myogenesis. The embryos were then dissected immediately after treatment on ED 10 or 13 to assess body, liver, and heart weights as well as to analyze breast and leg muscle fibers for their mitochondrial respiratory activity (MRA). Breast muscle samples were additionally used to evaluate the activity of enzymes involved in energy metabolism and cell-cycle progression. ED-10 embryos incubated at 38.8°C showed elevated weights (body, liver, and heart), MRA, and activities of lactate dehydrogenase and cytochrome oxidase compared to the ED-10 embryos incubated at 36.8°C. Similarly, the ED-13 embryos incubated at 38.8°C showed elevated body weight, MRA, and activities of glycogen phosphorylase, phosphofructokinase, and cytochrome oxidase compared to their 36.8°C counterparts. Embryos incubated at the normal temperature (37.8°C), however, showed variable differences from those incubated at 38.8°C versus 36.8°C. Cell-cycle enzyme activities were not impacted by the different temperature treatments. Thus, an increase or decrease in the incubation temperature during embryonic broiler myogenesis results in altered embryo activity, muscle energy metabolism, and activity-dependent muscle growth.
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http://dx.doi.org/10.1002/mrd.22596DOI Listing
January 2016

Influencing factors and applicability of the viability EMA-qPCR for a detection and quantification of Campylobacter cells from water samples.

PLoS One 2014 20;9(11):e113812. Epub 2014 Nov 20.

Institute of Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.

In recent years, increasing numbers of human campylobacteriosis cases caused by contaminated water have been reported. As the culture-based detection of Campylobacter is time consuming and can yield false-negative results, the suitability of a quantitative real-time PCR method in combination with an ethidium monoazide pretreatment of samples (EMA-qPCR) for the rapid, quantitative detection of viable Campylobacter cells from water samples was investigated. EMA-qPCR has been shown to be a promising rapid method for the detection of viable Campylobacter spp. from food samples. Application of membrane filtration and centrifugation, two methods frequently used for the isolation of bacteria from water, revealed a mean loss of up to 1.08 log10 cells/ml from spiked samples. Both methods used alone lead to a loss of dead bacteria and accumulation of viable bacteria in the sample as shown by fluorescence microscopy. After filtration of samples, no significant differences could be detected in subsequent qPCR experiments with and without EMA pretreatment compared to culture-based enumeration. High correlations (R(2)= 0.942 without EMA, R(2) = 0.893 with EMA) were obtained. After centrifugation of samples, qPCR results overestimated Campylobacter counts, whereas results from both EMA-qPCR and the reference method were comparable. As up to 81.59% of nonviable cells were detected in pond water, EMA-qPCR failed to detect correct quantities of viable cells. However, analyses of spiked tap water samples revealed a high correlation (R(2) = 0.863) between results from EMA-qPCR and the reference method. After membrane filtration, EMA-qPCR was successfully applied to Campylobacter field isolates, and results indicated an advantage over qPCR by analysing defined mixtures of viable and nonviable cells. In conclusion, EMA-qPCR is a suitable method to detect viable Campylobacter from water samples, but the isolation technique and the type/quality of the water sample impact the results.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0113812PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4239115PMC
December 2015

Comparative analysis and limitations of ethidium monoazide and propidium monoazide treatments for the differentiation of viable and nonviable campylobacter cells.

Appl Environ Microbiol 2014 Apr 31;80(7):2186-92. Epub 2014 Jan 31.

Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.

The lack of differentiation between viable and nonviable bacterial cells limits the implementation of PCR-based methods for routine diagnostic approaches. Recently, the combination of a quantitative real-time PCR (qPCR) and ethidium monoazide (EMA) or propidium monoazide (PMA) pretreatment has been described to circumvent this disadvantage. In regard to the suitability of this approach for Campylobacter spp., conflicting results have been reported. Thus, we compared the suitabilities of EMA and PMA in various concentrations for a Campylobacter viability qPCR method. The presence of either intercalating dye, EMA or PMA, leads to concentration-dependent shifts toward higher threshold cycle (CT) values, especially after EMA treatment. However, regression analysis resulted in high correlation coefficient (R(2)) values of 0.99 (EMA) and 0.98 (PMA) between Campylobacter counts determined by qPCR and culture-based enumeration. EMA (10 μg/ml) and PMA (51.10 μg/ml) removed DNA selectively from nonviable cells in mixed samples at viable/nonviable ratios of up to 1:1,000. The optimized EMA protocol was successfully applied to 16 Campylobacter jejuni and Campylobacter coli field isolates from poultry and indicated the applicability for field isolates as well. EMA-qPCR and culture-based enumeration of Campylobacter spiked chicken leg quarters resulted in comparable bacterial cell counts. The correlation coefficient between the two analytical methods was 0.95. Nevertheless, larger amounts of nonviable cells (>10(4)) resulted in an incomplete qPCR signal reduction, representing a serious methodological limitation, but double staining with EMA considerably improved the signal inhibition. Hence, the proposed Campylobacter viability EMA-qPCR provides a promising rapid method for diagnostic applications, but further research is needed to circumvent the limitation.
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http://dx.doi.org/10.1128/AEM.03962-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993131PMC
April 2014

Influence of modified atmosphere packaging on meat quality parameters of turkey breast muscles.

J Food Prot 2014 Jan;77(1):127-32

Institute of Food Quality and Food Safety, Foundation University of Veterinary Medicine, D-30173 Hannover, Germany.

Poultry meat is often stored in modified atmosphere packaging (MAP) or vacuum packaging to improve consumer acceptance and shelf life. The aim of this study was to determine how different packaging conditions influence meat quality. Therefore, in three independent experiments, turkey breast muscle cutlets were packaged either in vacuum or in different modified atmosphere mixtures (80% O2, 20% CO2 [MAP 1]; 80% N2, 20% CO2 [MAP 2]; and 20% O2, 20% CO2, 60% N2 [MAP 3]) and stored for 12 days at 3°C. Color, pH, electrical conductivity, total viable counts, and Pseudomonas species were determined on days 1, 4, 8, and 12 of storage. On the same days, samples were collected for analysis of thiobarbituric acid-reactive substance and total volatile basic nitrogen concentrations. Sensory parameters and liquid loss were determined on days 4, 8, and 12. Vacuum-packaged meat had the highest liquid loss and lowest sensory results. MAP 1-packaged meat showed the highest sensory, redness, and thiobarbituric acid-reactive substance values. MAP 2-packaged meat had lower sensory values. MAP 3-packaged meat had lower redness and sensory values, especially at the end of storage. The study showed an impact of the packaging condition on different quality parameters, with a small advantage for storage of turkey cutlets in high-oxygen packages.
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http://dx.doi.org/10.4315/0362-028X.JFP-13-242DOI Listing
January 2014

Influence of intermittent administration of parathyroid hormone on muscle tissue and bone healing in orchiectomized rats or controls.

J Endocrinol 2011 Apr 13;209(1):9-19. Epub 2011 Jan 13.

Department of Trauma Surgery and Reconstructive Surgery, University of Goettingen, Robert-Koch 40, 37075 Goettingen, Germany.

Influence of human parathyroid hormone (hPTH 1-34) on muscle and bone healing was studied in either orchiectomized (Orx at 8 months of age) or sham-operated male rats. Eleven-month-old Sprague-Dawley rats underwent bilateral transverse metaphyseal osteotomy of tibia and were divided into four groups (n=12): 1) sham-vehicle, 2) sham group-PTH everyday, 3) Orx-vehicle, 4) Orx-PTH everyday, and 5) Orx-PTH every other day. PTH dosage was 40  μg/kg body weight. After 5 weeks, fiber cross-sectional area, capillary density, and enzyme activity (lactate dehydrogenase, citrate synthase, and complex I) were measured in soleus (MS), gastrocnemius (MG), and longissimus (ML) muscles; tibiae were analyzed by computed tomographical, histological, and gene expression analyses. The effect of PTH in all rats was increased serum osteocalcin, cortical and callus densities and callus area. In sham rats capillary density was increased in limb muscles (MS: 1.3-1.7, MG: 1.2-1.4 capillaries/fiber), and rate of osseous bridging of osteotomy was enhanced (67-100%). In Orx rats serum creatine kinase was decreased (6670-2847 U/l), and bone genes (Igf-1, osteoprotegerin, and receptor activator of nuclear factor kB ligand) were up-regulated. Cross-sectional area, enzyme activity, food intake, weight of body, visceral organs, adipose tissue, MG, and MS were not affected by PTH. PTH had a favorable effect on muscle capillary density and improved bone healing being more effective in sham rats and having no adverse systemic effect. The effect was less if PTH was applied every other day. The findings may show up trends for therapeutic treatment of male patients.
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http://dx.doi.org/10.1530/JOE-10-0353DOI Listing
April 2011

In vitro maturation of bovine oocytes requires polyadenylation of mRNAs coding proteins for chromatin condensation, spindle assembly, MPF and MAP kinase activation.

Anim Reprod Sci 2002 Oct;73(3-4):129-40

Department of Reproductive Medicine, School of Veterinary Medicine, Buenteweg 15, D-30559 Hannover, Germany.

In the oocyte mRNA molecules are stored in order to be used during the maturation process when transcription is silenced. Translational activation of stored mRNA templates commonly is correlated with their cytoplasmic polyadenylation. In the present study, the effects of cordycepin, a potent polyadenylation inhibitor, on the in vitro maturation MPF and MAP kinase activation of bovine cumulus oocyte complexes (COCs) were examined. The presence of cordycepin (5 microg/ml) during the whole culture period (24 h) prevents chromatin condensation and germinal vesicle breakdown (GVBD) as well as MPF and MAP kinase activation. When COCs were first cultivated in inhibitor-free medium for 6 or 9 h and subsequently transferred to cordycepin supplemented medium for further 18 or 15 h neither MPF nor MAP kinase became activated and 86 and 85%, respectively, of the oocytes underwent GVBD but failed to form a spindle and hypercondensed their chromatin. Extending the first culture period in inhibitor-free medium to 12 or 15 h before transferring the COCs to cordycepin supplemented medium for a further 12 or 9 h allowed 48 and 79%, respectively of oocytes to reach the metaphase 2 (M 2) stage. From these data, it is concluded that mRNA molecules coding for proteins required for chromatin condensation and GVBD become polyadenylated during the first 6 h following the onset of culture whereas mRNA molecules coding for proteins required for spindle assembly of metaphase 1 (M 1) and MPF and MAP kinase activation become polyadenylated between 9 and 12 h following initiation of culture.
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http://dx.doi.org/10.1016/s0378-4320(02)00131-8DOI Listing
October 2002
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