Effects of diet forage proportion on maintenance energy requirement and the efficiency of metabolizable energy use for lactation by lactating dairy cows.

The objective of the present study was to examine the effect of dietary forage proportion (FP) on metabolizable energy (ME) requirement for maintenance (MEm) and the efficiency of ME use for lactation (kl) in lactating dairy cows. Data used were derived from 32 calorimetric chamber experiments undertaken at our institute between 1992 and 2010, including data from 818 Holstein-Friesian cows (HF), 50 Norwegian Red cows, and 62 crossbred cows (Jersey × HF or Norwegian Red × HF). Animals were offered forage-only rations (n=66) or forage and concentrate rations (n=864) with FP ranging from 18 to 100% (dry matter basis). The effect of FP was evaluated by dividing the whole data set into 4 groups according to the FP ranges, categorized as FP <30%, FP=30 to 59%, FP=60 to 99%, and FP=100%. The MEm for individual cows was calculated from heat production minus energy losses from inefficiencies of ME use for lactation, energy retention and pregnancy, and kl was obtained from milk energy output adjusted to zero energy balance (El(0)) divided by ME available for production. Increasing FP significantly reduced ME intake and milk energy output, although the differences between the 2 low FP groups were not significant. However, increasing FP significantly increased the ratio of heat production over ME intake and MEm (MJ/kg(0.75)), with the exception that the increases did not reach significance in heat production/ME intake between FP <30% and FP=30 to 59%, or in MEm between FP=60 to 99% and FP=100%. However, the FP had no significant effect on the kl values, which were similar among the 4 groups of cows. The effect of FP was also evaluated using the linear mixed regression technique relating El(0) to ME intake. The results demonstrated that with a common regression coefficient (slope), the regression constants (intercepts) taken as net energy requirement for maintenance significantly increased with increasing FP. However, the increase between the 2 high FP groups did not research significance. It is concluded that increasing diet FP had no effects on kl but significantly increased maintenance energy requirement (MJ/kg(0.75)). These results indicate that using the current energy feeding systems to ration dairy cows managed under low input systems may underestimate their nutrient requirements, because the majority of feeding systems adopted globally do not differentiate the maintenance energy requirements between low and high forage input systems.

Is there a relationship between genetic merit and enteric methane emission rate of lactating Holstein-Friesian dairy cows?

The present study was undertaken to examine the effect of cow genetic merit on enteric methane (CH4) emission rate. The study used a data set from 32 respiration calorimeter studies undertaken at this Institute between 1992 and 2010, with all studies involving lactating Holstein-Friesian dairy cows. Cow genetic merit was defined as either profit index (PIN) or profitable lifetime index (PLI), with these two United Kingdom genetic indexes expressing the expected improvement in profit associated with an individual cow, compared with the population average. While PIN is based solely on milk production, PLI includes milk production and a number of other functional traits including health, fertility and longevity. The data set had a large range in PIN (n=736 records, -£30 to +£63) and PLI (n=548 records, -£131 to +£184), days in milk (18 to 354), energy corrected milk yield (16.0 to 45.6 kg/day) and CH(4) emission (138 to 598 g/day). The effect of cow genetic merit (PIN or PLI) was evaluated using ANOVA and linear mixed modelling techniques after removing the effects of a number of animal and diet factors. The ANOVA was undertaken by dividing each data set of PIN and PLI into three sub-groups (PIN:£15, PLI:£67) with these being categorised as low, medium and high genetic merit. Within the PIN and PLI data sets there was no significant differences among the three sub-groups in terms of CH(4) emission per kg feed intake or per kg energy corrected milk yield, or CH(4) energy (CH(4)-E) output as a proportion of energy intake. Linear regression using the whole PIN and PLI data sets also demonstrated that there was no significant relationship between either PIN or PLI, and CH(4) emission per kg of feed intake or CH(4)-E output as a proportion of energy intake. These results indicate that cow genetic merit (PIN or PLI) has little effect on enteric CH(4) emissions as a proportion of feed intake. Instead enteric CH(4) production may mainly relate to total feed intake and dietary nutrient composition.

Occurrence, antibiotic resistance and molecular characterization of Listeria monocytogenes in the beef chain in the Republic of Ireland.

This study investigated the occurrence, concentration and key characteristics of Listeria monocytogenes in beef chain samples (n=1100) over a 2-year period (July 2007-June 2009). Listeria monocytogenes was isolated from bovine hides (27%), pre-chill carcasses (14%) and ground beef (29%), but not from ready-to-eat (RTE) beef. The concentration of the pathogen in the majority (95%) of contaminated samples was low and detected by enrichment only. The highest concentrations recovered (100-200 CFU/g) were in ground beef samples. The most commonly isolated serotype group was 1/2a (58%) followed by 4b (12%), 1/2b (10%) and 1/2c (6%). A small portion (<5%) isolates had demonstrated resistance to key anti-microbials including ampicillin, vancomycin and gentamycin which are recommended treatment options for listeriosis. Pulsed-field gel electrophoresis showed indistinguishable profiles for a number of isolates recovered from the hide and carcass (after slaughter and dressing) of the same animals, highlighting the role of hides as a source of contamination. Equally, indistinguishable pulsotypes for isolates recovered at different stages and time points (up to 6 months apart) in the beef chain demonstrated the persistence of specific clones in the factory, process and distribution environments. Overall, the study demonstrated a high prevalence of clinically significant L. monocytogenes entering and progressing along the beef chain and highlights the needs to control cross-contamination during beef processing and distribution and the need for thorough cooking of raw beef products.

Comparison of maintenance energy requirement and energetic efficiency between lactating Holstein-Friesian and other groups of dairy cows.

The objectives of the present study were to investigate the effects of cow group on energy expenditure and utilization efficiency. Data used were collated from 32 calorimetric chamber experiments undertaken from 1992 to 2010, with 823 observations from lactating Holstein-Friesian (HF) cows and 112 observations from other groups of lactating cows including Norwegian (n=50), Jersey × HF (n=46), and Norwegian × HF (n=16) cows. The metabolizable energy (ME) requirement for maintenance (MEm) for individual cows was calculated from heat production (HP) minus energy losses from inefficiencies of ME use for lactation, energy retention, and pregnancy. The efficiency of ME use for lactation (kl) was obtained from milk energy output adjusted to zero energy balance (El(0)) divided by ME available for production. The effects of cow groups were first evaluated using Norwegian cows against HF crossbred cows (F1 hybrid, Jersey × HF and Norwegian × HF). The results indicated no significant difference between the 2 groups in terms of energy digestibility, ratio of ME intake over gross energy intake, MEm (MJ per kg of metabolic body weight, MJ/kg(0.75)), or kl. Consequently, their data were combined (categorized as non-HF cows) and used to compare with those of HF cows. Again, we detected no significant difference in energy digestibility, ratio of ME intake over gross energy intake, MEm (MJ/kg(0.75)), or kl between non-HF and HF cows. The effects were further evaluated using linear regression to examine whether any significant differences existed between HF and non-HF cows in terms of relationships between ME intake and energetic parameters. With a common constant, no significant difference was observed between the 2 groups of cows in coefficients in each set of relationships between ME intake (MJ/kg(0.75)) and MEm (MJ/kg(0.75)), El(0) (MJ/kg(0.75)), HP (MJ/kg(0.75)), MEm:ME intake, El(0):ME intake, or HP:ME intake. However, MEm values (MJ/kg(0.75)) were positively related to ME intake (MJ/kg(0.75)), irrespective of cow group. We concluded, therefore, that cow groups evaluated in the present study had no significant effects on energy expenditure or energetic efficiency. However, the maintenance energy requirement (MJ/kg(0.75)) was not constant (as adopted in the majority of energy rationing systems across the world) but increased with increasing feed intake.

Prediction of manure nitrogen and organic matter excretion for young Holstein cattle fed on grass silage-based diets.

The objectives of the present study were to evaluate the effects of sex (steers vs. heifers) of young Holstein cattle on N and OM excretion in feces and urine and to use these data to develop prediction models for N and OM excretion. Data used were derived from a study with 20 autumn-born Holstein cattle (10 steers and 10 heifers) with N and OM intake and output measured at age of 6, 12, 18, and 22 mo, respectively. The cattle were offered a typical diet used on U.K. commercial farms containing a single grass silage mixed with concentrates. In each period, the cattle were housed as a single group in cubicle accommodation for the first 20 d, individually in metabolism units for the next 3 d, and then in calorimeter chambers for the final 5 d with feed intake, feces, and urine excretion measured during the final 4 d. Within each period, sex had no effect (P > 0.05) on N or OM intake or excretion or N utilization efficiency, with exceptions of steers having a greater intake of N (P = 0.036) and OM (P = 0.018) at age of 18 mo and a lower ratio of fecal N:N intake (P = 0.023) at age of 6 mo. A range of regression relationships (P < 0.05) were developed for prediction of N (g/d) and OM (kg/d) excretion in feces and urine. The present data were also used to calculate accumulated N and OM intake (kg) and excretion for the 2 sexes. Sex had no effects (P > 0.05) on accumulated N or OM intake or N or OM excretion in feces and urine or retained N and OM during the first or second year of life. On average for the 2 sexes at first and second year of age, the accumulated N excretions in feces were 11.4 and 21.1 kg and in urine 11.6 and 30.6 kg, respectively, and the corresponding values for accumulated OM excretions were respectively 241.5, 565.7, 30.3 and 81.5 kg. A number of equations were developed to predict accumulated N and OM excretion in feces and urine (kg) using BW (kg; P < 0.001, r(2) = 0.95 to 0.97). The accurate prediction of N and OM excretion in feces and urine is essential for reducing N pollution to ground and surface water and calculating methane and nitrous oxide emissions from manure management of dairy and beef production systems. These data can add novel information to the scientific literature and can be used to improve national inventories of manure N output and greenhouse gas emissions and to develop appropriate mitigation strategies for young Holstein cattle.

Airborne Salmonella and Listeria associated with Irish commercial beef, sheep and pig plants.

Air samples from lairage, hide/fleece pulling or dehairing/scraping, evisceration and chilling areas in commercial beef, sheep and pig plants were examined for Salmonella spp. and Listeria monocytogenes, by impaction or sedimentation onto selective (Brilliant Green Agar, BSA; Listeria Selective Agar, LSA) and non-selective (Plate Count Agar, PCA) media. Both pathogens were frequently detected in all three plants. Improved recoveries were achieved by combining sedimentation, and broth based resuscitation, suggesting cell injury. Salmonella were recovered from all three plants, with the highest counts on BGA in the pig plant. The most common serotypes were S. Typhimurium in the beef/sheep plants and S. Derby in the pig plant. Very low counts of L. monocytogenes (e.g. 2.6CFUm(2)) were detected at hide removal on LSA sedimentation plates in the beef plant. These included serogroup 1/2a-3a and 1/2b-3b-7. Pathogen counts in the three plants were generally very low, suggesting that air is unlikely to be a significant source of carcass or plant surface contamination.

Prevalence and characteristics of Salmonella in the beef chain in the Republic of Ireland.

The study investigated the prevalence, concentration and characteristics of Salmonella spp. in the Irish beef chain. A total of 900 samples including bovine hides, carcasses and ground beef were examined for the pathogen over a 2-year study (July 2007-June 2009). Salmonella prevalence was low in all sample types; bovine hide (0.75%, 3 of 400); carcasses (0.25%, 1 of 400); and ground beef (3%, 3 of 100). All positive samples contained the pathogen in low concentrations (<10 CFU per cm(2) or per g). Serovars recovered were S. Dublin from hide and carcasses and S. Braenderup in ground beef. All isolates were susceptible to 13 anti-microbials. The study highlights that Salmonella can be found at low levels at all stages of beef chain production, processing and retail and that there is a need for multiple hurdle interventions and practices along the beef chain, which will reduce consumer exposure to this pathogen.

An investigation of the immediate and storage effects of chemical treatments on Campylobacter and sensory characteristics of poultry meat.

Campylobacteriosis is the most common foodborne bacterial infection in developed countries and many cases are associated with poultry. This study investigated the immediate and storage effect of dipping inoculated poultry skin samples in trisodium phosphate (TSP, 10 & 14%, w/v), lactic acid (LA, 1 & 5%, v/v), citric acid (CA, 1 & 5%, w/v), peroxyacids (POA, 100 & 200 ppm) and acidified sodium chlorite (ASC, 500 & 1200 ppm). Spray application was also tested using the higher concentrations in the laboratory. In a broiler processing plant the efficacy of using TSP (14%) and CA (5%) applied by immersion and spray was investigated using naturally contaminated carcasses and the effect of these treatments on the sensory attributes of a skin-on (drumstick) and skin-off (fillet) raw and cooked product was assessed using descriptive sensory analysis. In the laboratory, immersion in TSP (14%), LA (5%), CA (5%) and ASC (1200 ppm) significantly (P<0.05) reduced the Campylobacter counts and a 2.5 to 3 log10 cfu/cm(2) reduction was observed within the shelf-life (3-5 days) of poultry meat. Spraying was ineffective even after storage. In the broiler processing plant, immersion in TSP (14%) or CA (5%) achieved Campylobacter reductions of 2.49 and 1.44 log10 cfu/cm(2), respectively. There were no significant differences between the treatments for any of the attributes measured in either raw or cooked drumsticks. The 'colour' of raw chicken fillets treated with both TSP (14%, w/v) and CA (5%, w/v) was significantly (P≤0.05) lighter than that of control samples. The 'intensity of chicken odour' and the perception of 'salt' in cooked chicken fillets treated with CA (5%, w/v) were also significantly (P≤0.05) higher than that of either control or TSP (14%, w/v) treated samples. It was concluded that TSP (14%) or CA (5%) could be applied to significantly reduce Campylobacter contamination of broilers without adversely affecting the sensory quality of the product.

Occurrence and characteristics of fastidious Campylobacteraceae species in porcine samples.

This study investigated the prevalence and characteristics of Campylobacteraceae including a range of fastidious species in porcine samples. Over a thirteen month period caecal contents (n=402) and pork carcass swabs (n=401) were collected from three pork abattoirs and pork products (n=399) were purchased at point of sale in the Republic of Ireland. Campylobacteraceae isolates were recovered by enrichment, membrane filtration and incubation in antibiotic free media under a modified atmosphere (3% O2, 5% H2, 10% CO2 and 82% N2). Campylobacteraceae isolates were identified as either genus Campylobacter or Arcobacter and then selected species were identified by Polymerase Chain Reaction (PCR). Campylobacteraceae were isolated from 103 (26%) caecal samples, 42 (10%) carcass swabs, and 59 (15%) pork products. Campylobacter coli was the most commonly isolated species found in (37%) all sample types but many fastidious species were also isolated including Campylobacter concisus (10%), Arcobacter butzleri (8%), Campylobacter helveticus (8%), Campylobacter mucosalis (6%), Arcobacter cryaerophilus (3%), Campylobacter fetus subsp. fetus (1%), Campylobacter jejuni subsp. jejuni (1%), Campylobacter lari (0.5%), Campylobacter curvus (0.5%) and Arcobacter skirrowii (0.5%). Among all isolates, 83% contained cadF and 98% flaA. In this study 35% of porcine C. coli were resistant to ciprofloxacin but none of the fastidious species demonstrated any resistance to this drug. The level of resistance to erythromycin was very high (up to 100%) in C. concisus and C. helveticus and this is a real concern as this is the current empiric drug of choice for treatment of severe gastroenteritic Campylobacter infections. The study shows that there is a much wider range of fastidious Campylobacteraceae present in porcine samples than previously assumed with C. concisus the second most common species isolated. The majority of fastidious Campylobacteraceae isolates obtained contained virulence genes and antibiotic resistance indicating potential public health significance.

Transfer of verocytotoxigenic Escherichia coli O157, O26, O111, O103 and O145 from fleece to carcass during sheep slaughter in an Irish export abattoir.

The purpose of this study was to investigate carriage and transfer of verocytotoxigenic Escherichia coli (VTEC) O157, O26, O111, O103 and O145 from fleece to dressed carcasses of 500 sheep, and to establish the virulence potential of recovered VTEC. Individual sheep were tracked and sampled (10 g fleece, full carcass swab) through the slaughter process. Samples were examined for the presence of verotoxin (vt1 and vt2) genes using a duplex real-time PCR assay and positive samples were further screened for the presence of the above five serogroups by real-time PCR. VTEC cells were recovered from PCR positive samples by serogroup specific immunomagnetic separation and confirmed by serogroup specific latex agglutination and PCR. Isolates were subject to a virulence screen (vt1, vt2, eaeA and hlyA) by PCR and isolates carrying vt genes were examined by Pulsed-Field Gel Electrophoresis (PFGE). VTEC O26 was recovered from 5/500 (1.0%) fleece and 2/500 (0.4%) carcass samples. VTEC O157 was isolated from 4/500 (0.8%) fleece samples and 3/500 (0.6%) carcass samples. E. coli O103 was recovered from 84/500 (16.8%) fleece and 68/500 (13.6%) carcasses, but only one E. coli O103 isolate (0.2%) carried vt genes. E. coli O145 was recovered from one fleece sample, but did not carry vt genes. E. coli O111 was not detected in any samples. For the four serogroups recovered, the direct transfer from fleece to carcass was not observed with PFGE showing that VTEC O26 isolates from a matched fleece/carcass "pair" were not identical. This study shows that while VTEC O157 are being carried by sheep presented for slaughter in Ireland, other potentially clinically significant verotoxin producing strains (particularly VTEC O26) are emerging.

Chlamydia pneumoniae antibodies and C-reactive protein levels in patients with abdominal aortic aneurysms.

INTRODUCTION: The study aim was to assess the relationship between the presence of antibodies to Chlamydia pneumoniae and abdominal aortic aneurysm (AAA) incidence. PATIENTS AND METHODS: Consecutive AAA patients and AAA-free controls were recruited prospectively. Serum samples from both groups were examined to determine Immunoglobulin (Ig) A and IgG titres against Chlamydia pneumoniae by ELISA and C-reactive protein (CRP) concentrations. Results were expressed as mean (SD) or median (IQR) and compared using χ (2) and Mann-Whitney U tests. A P value of <0.05 was considered statistically significant. RESULTS: Each study group (AAA/nAAA) comprised 250 patients. 196 (78.7%) AAA patients had positive IgA antichlamydial antibody titres, compared to 181 (72.4%) in the control group (P = 0.008, OR 2.0, 95% CI 1.2-3.5). However, positive IgG antibody titres were similar (191 versus 203; P = 0.222, OR 0.7, 95% CI 0.4-1.3). Average CRP concentrations were higher in AAA individuals. IgA or IgG antibody titres were not related to CRP concentrations. CONCLUSIONS: These results demonstrated that the frequent incidence of Chlamydia pneumoniae antibodies within the general population makes it difficult to relate its presence to AAA development, despite the high IgA antibody titres. In addition, raised CRP concentrations in AAA patients are not related to the presence of antichlamydial antibodies.

The effect of urea and ammonia treatments on the survival of Salmonella spp. and Yersinia enterocolitica in pig slurry.

AIMS: The objective of this study was to investigate the survival of Salmonella and Yersinia enterocolitica strains in pig slurry and evaluate urea and ammonia as disinfection strategies. METHODS AND RESULTS: Salmonella Anatum, Salmonella Derby, Salmonella Typhimurium DT19 and Y. enterocolitica bioserotypes 4, O:3, 2, O:5,27 and 1A, O:6,30 were selectively marked by insertion of the plasmid, pGLO encoding for green fluorescent protein and for ampicillin resistance. Strain cocktails were inoculated into fresh pig slurry (control), slurry treated with urea [final concentration 2% w/w, (0.33 mol l(-1) )] and slurry treated with ammonia [final concentration 0.5% w/w, (0.3 mol l(-1) )] and stored at 4, 14 and 25°C. Bacterial counts were determined at regular intervals on xylose lysine deoxycholate agar (XLD), and XLD supplemented with ampicillin (0.1 mg ml(-1) ) and arabinose (0.6 mg ml(-1) ) for Salmonella and cefsulodin-irgasan-novobiocin agar (CIN) and CIN supplemented with ampicillin and arabinose for Y. enterocolitica. The pH of the control-, urea- and ammonia-treated samples ranged from 7.1 to 7.7, 8.8 to 8.9 and 8.0 to 8.3, respectively. Salmonella D(4) values ranged from 2.71 to 21.29 days, D(14) values from 2.72 to 11.62 days and D(25) values from 1.76 to 6.85 days. The equivalent D values ranges for the Y. enterocolitica strains were 3.7-19.23, 1.8-16.67 and 1.63-7.09 days, respectively. Treatment significantly (P < 0.01) affected D values with control > ammonia > urea, as did incubation temperature; 4 > 14 > 25°C. CONCLUSIONS: Urea and to a lesser extent ammonia may be used to disinfect Salmonella- and/or Y. enterocolitica-contaminated pig slurry, decreasing the storage time required while increasing its fertilizer value. SIGNIFICANCE AND IMPACT OF THE STUDY: This study presents data supporting the treatment of pig slurry to kill important zoonotic agents, thereby reducing environmental contamination, cross-infection of other animals and decreasing zoonotic disease in the food chain.

Enteric methane emissions and efficiency of use of energy in Holstein heifers and steers at age of six months.

Twenty 5-mo-old Holstein cattle (10 steers and 10 heifers) were selected from a dairy herd for a 28 d study of enteric methane emissions and energy utilization. The cattle were offered a completely mixed diet with grass silage and concentrates (0.45 and 0.55, DM basis, respectively). They were housed as a single group in cubicle accommodation for the first 20 d, transferred to metabolism units for 3 d, and subsequently housed in indirect open-circuit respiration calorimeter chambers for next 5 d with measurements of feed intake, feces and urine outputs, and gaseous exchange. There were no significant differences (P>0.05) between the 2 groups in terms of animal performance (feed intake, BW, or BW gain), energy metabolism (energy intake, energy outputs, or energy use efficiency), or methane emission rates (total methane emissions expressed on feed intake or energy intake basis). Therefore, the data from the 2 groups were pooled to develop a range of relationships between inputs and outputs. The regression of energy balance or heat production against ME intake (r2=0.85; P<0.001) indicated a NEm of 0.57 MJ/kg BW0.75, which is greater than reported for adult dairy cattle. The methane energy output was found to be 0.068 of GE intake when the intercept was omitted from the linear equation (r2=0.73; P<0.001), which is greater than the commonly accepted value (0.065) for adult cattle used for development of methane emission inventories for dairy and beef production systems. These data can add useful information, as there is little information available on measurements of maintenance energy requirement or methane emissions in young stock (6 mo old) of the current high-yielding dairy cattle. The use of these data can potentially improve the accuracy of prediction of energy requirement and methane emissions for dairy and beef production systems in these dietary conditions.

Comparison of aerial counts at different sites in beef and sheep abattoirs and the relationship between aerial and beef carcass contamination.

The study examined and compared levels of aerial contamination in commercial beef and sheep plants at four sites, i.e. lairage, hide/fleece pulling, evisceration and chilling. Aerial contamination was determined by impaction and sedimentation onto Plate Count Agar to enumerate Total Viable Counts, MacConkey Agar to enumerate coliforms and Violate Red Bile Glucose Agar to enumerate Enterobacteriaceae. AS I cannot see any difference in the text here - I am not sure what the change is?. The levels of aerial contamination were similar at equivalent sites in beef and sheep plants, irrespective of the sampling method or the type of organisms recovered. Mean log counts recovered on each medium in the chillers were generally significantly lower (P < .05) than the corresponding mean log numbers recovered at the other three sites. The relationship between impaction (air) and sedimentation (surface) counts could be described by the surface to air ratio (SAR) which in this study had an R(2) of 0.77. Further studies in an experimental plant compared counts recovered from the neck of beef carcasses with aerial counts determined by impaction and sedimentation onto agar and irradiated meat pieces. A relationship between counts on beef carcasses and in the air could not be established, irrespective of the method used to compare counts.

Tracking verocytotoxigenic Escherichia coli O157, O26, O111, O103 and O145 in Irish cattle.

The purpose of this study was to investigate carriage and transfer of verocytotoxigenic Escherichia coli (VTEC) O157, O26, O111, O103 and O145 from faeces and hide to dressed carcasses of Irish cattle as well as establishing the virulence potential of VTEC carried by these cattle. Individual cattle was tracked and faecal samples, hide and carcass (pre-evisceration and post-wash) swabs were analysed for verotoxin (vt1 and vt2) genes using a duplex real-time PCR assay. Positive samples were screened for the five serogroups of interest by real-time PCR. Isolates were recovered from PCR positive samples using immunomagnetic separation and confirmed by latex agglutination and PCR. Isolates were subject to a virulence screen (vt1, vt2, eaeA and hlyA) by PCR. Isolates carrying vt genes were examined by Pulsed-Field Gel Electrophoresis (PFGE). Of the VTEC isolated, E. coli O157 was the most frequently recovered from hide (17.6%), faeces (2.3%) and pre-evisceration/post-wash carcass (0.7%) samples. VTEC O26 was isolated from 0.2% of hide swabs and 1.5% of faeces samples. VTEC O145 was isolated from 0.7% of faeces samples. VTEC O26 and VTEC O145 were not recovered from carcass swabs. Non-VTEC O103 was recovered from all sample types (27.1% hide, 8.5% faeces, 5.5% pre-evisceration carcass, 2.2% post-wash carcass), with 0.2% of hide swabs and 1.0% of faeces samples found to be positive for VTEC O103 isolates. E. coli O111 was not detected in any samples. For the four serogroups recovered, the direct transfer from hide to carcass was not observed. This study shows that while VTEC O157 are being carried by cattle presented for slaughter in Ireland, a number of other verotoxin producing strains are beginning to emerge.

Incidence and survival of non-O157 verocytotoxigenic Escherichia coli in soil.

AIMS: This study estimated the incidence of non-O157 verocytotoxigenic Escherichia coli (VTEC) in farm pasture soils and investigated the survival of non-O157 VTEC in clay and sandy loam soils. METHODS AND RESULTS: Twenty farms were tested over a 12-month period by sample enrichment in tryptone soya broth plus vancomycin, followed by PCR screening for the presence of vt1 and vt2 genes. Of the 600 soil samples, 162 (27%), across all farms, were found to contain vt1 and/or vt2 genes. The enrichment cultures from the 162 PCR-positive samples were plated onto Chromocult tryptone bile X-glucuronide agar (TBX), presumptive VTEC colonies recovered, confirmed as VTEC by PCR and serotyped. Samples of the two predominant soil types in Ireland (clay and sandy) were homogenized, characterized in terms of pH, boron, cobalt, copper, potassium, magnesium, manganese, phosphorus, zinc and organic matter content, inoculated with washed suspensions of eight non-O157:H7 soil isolates and six bovine faecal isolates and stored at 10°C for up to 201 days. Inoculum survival rates were determined at regular intervals by recovering and plating soil samples on TBX. All inoculated non-O157 serotypes had highest D-values in the sandy loam soil with D-values ranging from 50·26 to 75·60 days. The corresponding range in clay loam soils was 31·60-48·25 days. CONCLUSIONS: This study shows that non-O157 VTEC occur widely and frequently in pasture soils and can persist in such environments for several months, with considerable opportunity for recycling through farm environments, and cattle, with clear potential for subsequent transmission into the human food chain. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first such study of non-O157 VTEC in farm soils and found that these VTEC are frequent and persistent contaminants in farm soils. In light of recent epidemiological data, non-O157 VTEC should be seen as an emerging risk to be controlled within the food chain.

Diversity of culturable psychrophilic and psychrotrophic anaerobic bacteria isolated from beef abattoirs and their environments.

This study identified 431 psychrophilic or psychrotrophic isolates from commercial Irish beef abattoir environments and "blown packs" of vacuum-packed beef, using PCR and 16S rRNA sequencing, and estimated their intraspecies genetic diversity using restriction fragment length polymorphism (RFLP) analysis and spacer region PCR (SR-PCR). Twenty-five species were identified in the 431 isolates, with the most frequently recovered species being Clostridium gasigenes (n=315), Clostridium estertheticum (n=17), and a potentially novel species designated strain TC1 (n=52). These species were previously found to be associated with a particular type of spoilage known as blown-pack spoilage (BPS), which occurs in chilled-stored (i.e., -1.5°C to 4°C) vacuum-packaged meat within 2 to 4 weeks and involves the production of large volumes of gas. Overall, the study demonstrates the considerable and not previously reported diversity of the anaerobic microflora in abattoirs and the presence of a wide range of organisms capable of causing BPS at chilled temperatures.

A method for the growth and recovery of 17 species of Campylobacter and its subsequent application to inoculated beef.

The aim of this study was to develop a universal cultural protocol, which could facilitate the growth of 17 species and 3 subspecies of Campylobacter. Enrichment media including Campylobacter Enrichment Broth (CEB) and Bolton Broth were tested against a panel of Campylobacter strains (n=53) encompassing 17 species and 3 subspecies, under a gas atmosphere containing hydrogen (2.5% O(2), 7% H(2), 10% CO(2), and 80.5% N(2)). The impact of enrichment conditions on cell motility was also investigated using fluorescent microscopy. Membrane filtration was examined as a means of selectively recovering Campylobacter from enrichment media on two different non-selective agars, Anaerobe Basal Agar (ABA) and Tryptose Blood Agar (TBA). The results showed that enrichment in CEB for 24 h at 37°C under a modified gas atmosphere followed by centrifugation and membrane filtration onto ABA allowed recovery of all species (53 strains) of Campylobacter from inoculated meat samples. After 24 h enrichment, there were higher levels of motile Campylobacter in CEB than in Bolton broth and it is proposed that this attribute aided the passage of the Campylobacter through the membrane filter. The results of this study provide a simple, but effective method for the growth and recovery of a wide range of diverse Campylobacter spp. from a meat matrix using common cultural parameters.

The influence of storing beef aerobically or in vacuum packs on the shelf life of mince.

AIMS: To investigate the influence of aerobic or vacuum pack storage of beef trimmings on the microbiology, colour and odour of subsequently produced mince. METHODS AND RESULTS: Trimmings stored aerobically for 7 or 10 days and in vacuum packs for 7, 10, 14 or 22 days at 0 or 5°C were minced, stored aerobically at 0 or 5°C for up to 7 days and examined daily to determine Total viable, Pseudomonas, Lactic acid bacteria, Brochothrix thermosphacta, and Enterobacteriaceae counts, colour and odour. Mincing reduced counts, particularly of Pseudomonas, B. thermosphacta and Enterobacteriaceae, probably because of the action free radicals released from muscle and bacterial cells. Storage of vacuum-packed trimmings for 22 days resulted in improved mince colour and inhibition of the growth of Pseudomonas. CONCLUSIONS: The shelf life of mince from trimmings is directly influenced by the trimmings storage conditions, and longer-term vacuum storage of trimmings produced improvements in mince quality. SIGNIFICANCE AND IMPACT OF THE STUDY: There appears to be no scientific rationale for limiting the storage of vacuum packaging beef trimmings to 15 days, prior to mince production, as stated in EU 835/2004. This study identifies advantages in storing trimmings in vacuum packs for at least 21 days prior to mincing, in terms of improved mince quality.

Survival of Pseudomonas fluorescens on beef carcass surfaces in a commercial abattoir.

The influence of a commercial chilling process (18 h at 10 degrees C followed by up to 78 h at 2 degrees C) on Pseudomonas fluorescens inoculated on beef carcass surfaces at four sites, neck (NE), outside round (OR), brisket (BR) and foreshank/brisket (FB) before chilling ("hot inoculated") or after chilling for 24h ("cold inoculated") was investigated. Pseudomonas counts increased significantly at all sites on "hot inoculated" carcasses during storage, but on "cold inoculated" carcasses, counts declined or remained unchanged. On hot and cold inoculated carcasses, differences in Pseudomonas growth or survival were demonstrated between sites. No clear relationships were observed between Pseudomonas growth or survival and chiller relative humidity (RH) or surface water activity (a(w)) at the different sites. These results were unexpected, and are discussed in relation to environmental factors that affect the growth/survival of P. fluorescens on carcass surfaces during chilling i.e. temperature, RH, and the relationship of these parameters to surface water activity (a(w)).