The effect of transportation and lairage on faecal shedding and carcass contamination with Escherichia coli O157 and O26 in very young calves in New Zealand.

The effect of transportation and lairage on the faecal shedding and post-slaughter contamination of carcasses with Escherichia coli O157 and O26 in young calves (4-7-day-old) was assessed in a cohort study at a regional calf-processing plant in the North Island of New Zealand, following 60 calves as cohorts from six dairy farms to slaughter. Multiple samples from each animal at pre-slaughter (recto-anal mucosal swab) and carcass at post-slaughter (sponge swab) were collected and screened using real-time PCR and culture isolation methods for the presence of E. coli O157 and O26 (Shiga toxin-producing E. coli (STEC) and non-STEC). Genotype analysis of E. coli O157 and O26 isolates provided little evidence of faecal-oral transmission of infection between calves during transportation and lairage. Increased cross-contamination of hides and carcasses with E. coli O157 and O26 between co-transported calves was confirmed at pre-hide removal and post-evisceration stages but not at pre-boning (at the end of dressing prior to chilling), indicating that good hygiene practices and application of an approved intervention effectively controlled carcass contamination. This study was the first of its kind to assess the impact of transportation and lairage on the faecal carriage and post-harvest contamination of carcasses with E. coli O157 and O26 in very young calves.

Nationwide prevalence and risk factors for faecal carriage of Escherichia coli O157 and O26 in very young calves and adult cattle at slaughter in New Zealand.

Nationwide prevalence and risk factors for faecal carriage of Escherichia coli O157 and O26 in cattle were assessed in a 2-year cross-sectional study at four large slaughter plants in New Zealand. Recto-anal mucosal swab samples from a total of 695 young (aged 4-7 days) calves and 895 adult cattle were collected post-slaughter and screened with real-time polymerase chain reaction (PCR) for the presence of E. coli O157 and O26 [Shiga toxin-producing E. coli (STEC) and non-STEC]. Co-infection with either serogroup of E. coli (O157 or O26) was identified as a risk factor in both calves and adult cattle for being tested real-time PCR-positive for E. coli O157 or O26. As confirmed by culture isolation and molecular analysis, the overall prevalence of STEC (STEC O157 and STEC O26 combined) was significantly higher in calves [6·0% (42/695), 95% confidence interval (CI) 4·4-8·1] than in adult cattle [1·8% (16/895), 95% CI 1·1-3·0] (P < 0·001). This study is the first of its kind in New Zealand to assess the relative importance of cattle as a reservoir of STEC O157 and O26 at a national level. Epidemiological data collected will be used in the development of a risk management strategy for STEC in New Zealand.

Food control from farm to fork: implementing the standards of Codex and the OIE.

The Codex Alimentarius (Codex) international food standards help to ensure food safety and promote fair practices in the international food trade. Implementing these standards using a risk management framework (RMF) approach to decision-making is an increasingly common aspect of the food control programmes of national governments. The Codex Alimentarius Commission (CAC) provides guidance at both the system and food commodity levels. In the case of zoonoses, similarities in the risk analysis methodologies used to underpin standard setting by the CAC and the World Organisation for Animal Health (OIE) are highly enabling of integrated food control systems. The CAC and the OIE are increasingly working together to develop their respective standards for foodborne zoonoses and other hazards so that they are non-duplicative, cohesive and utilise the whole food chain. There is a clear need for effective integration of food safety and animal health monitoring and surveillance information to better control foodborne zoonoses. This is increasingly supported by Codex and OIE standards working together in a variety of ways and realisation of benefits is highly dependent on coordination and sharing of information between Competent Authorities and other food safety stakeholders at the national level.

Pasteurization of milk: the heat inactivation kinetics of milk-borne dairy pathogens under commercial-type conditions of turbulent flow.

This is the first study to report kinetic data on the survival of a range of significant milk-borne pathogens under commercial-type pasteurization conditions. The most heat-resistant strain of each of the milk-borne pathogens Staphylococcus aureus, Yersinia enterocolitica, pathogenic Escherichia coli, Cronobacter sakazakii (formerly known as Enterobacter sakazakii), Listeria monocytogenes, and Salmonella was selected to obtain the worst-case scenario in heat inactivation trials using a pilot-plant-scale pasteurizer. Initially, approximately 30 of each species were screened using a submerged coil unit. Then, UHT milk was inoculated with the most heat-resistant pathogens at ~10(7)/mL and heat treated in a pilot-plant-scale pasteurizer under commercial-type conditions of turbulent flow for 15s over a temperature range from 56 to 66°C and at 72°C. Survivors were enumerated on nonselective media chosen for the highest efficiency of plating of heat-damaged bacteria of each of the chosen strains. The mean log(10) reductions and temperatures of inactivation of the 6 pathogens during a 15-s treatment were Staph. aureus >6.7 at 66.5°C, Y. enterocolitica >6.8 at 62.5°C, pathogenic E. coli >6.8 at 65°C, C. sakazakii >6.7 at 67.5°C, L. monocytogenes >6.9 at 65.5°C, and Salmonella ser. Typhimurium >6.9 at 61.5°C. The kinetic data from these experiments will be used by the New Zealand Ministry of Agriculture and Forestry to populate the quantitative risk assessment model being developed to investigate the risks to New Zealand consumers from pasteurized, compared with nonpasteurized, milk and milk products.

Source attributed case-control study of campylobacteriosis in New Zealand.

BACKGROUND: Following an initial reduction in human campylobacteriosis in New Zealand after the implementation of poultry food chain-focused interventions during 2006-2008, further decline has been relatively small. We report a year-long study of notified campylobacteriosis cases, incorporating a case control study combined with a source attribution study. The purpose was to generate up-to-date evidence on the relative contributions of different sources of campylobacteriosis in New Zealand. METHODS: The study approach included: • A case-control study of notified cases (aged six months or more) sampled in a major urban centre (Auckland, every second case) and a mixed urban/rural area (Manawatu/Whanganui, every case), between 12 March 2018 and 11 March 2019. • Source attribution of human campylobacteriosis cases sampled from these two regions over the study period by modelling of multilocus sequence typing data of Campylobacter jejuni and C. coli isolates from faecal samples of notified human cases and relevant sources (poultry, cattle, sheep). RESULTS: Most cases (84%) were infected with strains attributed to a poultry source, while 14% were attributed to a cattle source. Approximately 90% of urban campylobacteriosis cases were attributed to poultry sources, compared to almost 75% of rural cases. Poultry consumption per se was not identified as a significant risk factor. However specific risk factors related to poultry meat preparation and consumption did result in statistically significantly elevated odds ratios. CONCLUSIONS: The overall findings combining source attribution and analysis of specific risk factors indicate that poultry meat remains a dominant pathway for exposure and infection.

Molecular and spatial epidemiology of human campylobacteriosis: source association and genotype-related risk factors.

The epidemiology of human campylobacteriosis is complex but in recent years understanding of this disease has advanced considerably. Despite being a major public health concern in many countries, the presence of multiple hosts, genotypes and transmission pathways has made it difficult to identify and quantify the determinants of human infection and disease. This has delayed the development of successful intervention programmes for this disease in many countries including New Zealand, a country with a comparatively high, yet until recently poorly understood, rate of notified disease. This study investigated the epidemiology of Campylobacter jejuni at the genotype-level over a 3-year period between 2005 and 2008 using multilocus sequence typing. By combining epidemiological surveillance and population genetics, a dominant, internationally rare strain of C. jejuni (ST474) was identified, and most human cases (65.7%) were found to be caused by only seven different genotypes. Source association of genotypes was used to identify risk factors at the genotype-level through multivariable logistic regression and a spatial model. Poultry-associated cases were more likely to be found in urban areas compared to rural areas. In particular young children in rural areas had a higher risk of infection with ruminant strains than their urban counterparts. These findings provide important information for the implementation of pathway-specific control strategies.

The role and functionality of Veterinary Services in food safety throughout the food chain.

Both national Veterinary Services and international standard-setting organisations have now embraced risk assessment as an essential tool for achieving their goals. Veterinarians have key roles in all aspects of the control of food-borne hazards of animal origin, but additional specialist skills are necessary for assessing, managing and communicating risk. Further, the deployment of Veterinary Services must reflect the multi-functional aspects of public and animal health activities. A generic risk management framework provides a systematic process whereby food safety standards and other measures are chosen and implemented on the basis of knowledge of risk and evaluation of other factors relevant to protecting human health and promoting non-discriminatory trade practices. In this context, a number of countries are exploring new administrative and structural arrangements for competent authorities. The traditional focus of veterinary involvement in food safety has been in meat hygiene at the level of the slaughterhouse. While this role continues, the emerging 'risk-based' approach to food control requires increased involvement in other segments of the meat food chain, as well as other areas such as production of milk and fish. This more extensive role requires a wider skill base and establishment of effective networks with a different range of stakeholders.

Oesophageal transit, disintegration and gastric emptying of a film-coated risedronate placebo tablet in gastro-oesophageal reflux disease and normal control subjects.

BACKGROUND: Risedronate sodium is a pyridinyl bisphosphonate, proven effective for the treatment and prevention of postmenopausal osteoporosis and glucocorticoid-induced osteoporosis and Paget's disease of the bone. AIM: To compare the oesophageal transit, disintegration and gastric emptying of the commercial film-coated risedronate tablet in subjects with gastro-oesophageal reflux disease (GERD) and normal control subjects. METHODS: A total of 30 subjects, 15 patients with GERD and 15 age- and sex-matched, normal control subjects, participated in a single-centre, open-label, comparative gamma scintigraphy study. The GERD subjects had active erosive oesophagitis within 4 weeks prior to dosing. RESULTS: The mean oesophageal transit (GERD, 4.4 s; controls, 3.1 s), mean disintegration (GERD, 21.8 min; controls, 19.2 min) and mean gastric emptying (GERD, 15.9 min; controls, 15.0 min) were similar in the two subject groups. The oesophageal transit is rapid and given the rapid disintegration and gastric emptying, oesophageal contact occurring via reflux of risedronate was unlikely since most, if not all, of the dosage form exited from the stomach within 30 min. CONCLUSIONS: The oval shape and film-coating on the commercial risedronate tablet promotes rapid oesophageal transit and minimizes oesophageal contact, even in the high-risk GERD population.

Haemolysis as a means of distinguishing between Leptospira interrogans serovars balcanica and hardjo.

Leptospira interrogans serovar balcanica was haemolytic for washed human, cattle, sheep and possum red blood cells (RBC); serovar hardjo was non-haemolytic. A test for haemolysis may prove useful in the preliminary differentiation of balcanica and hardjo isolates. Balcanica was non-haemolytic for unwashed RBC from human and bovine donors whose serum contained Hebdomadis serogroup antibody. Haemolytic activity tended to disappear with repeated subculture of balcanica.

Mineralocorticoids modulate central angiotensin II receptors in rats.

The effect of chronic administration of deoxycorticosterone acetate (DOCA) on the regulation of angiotensin II (AII) receptors in the brains of adult rats was compared with their drinking and pressor responsiveness to both peripheral and central administration of AII. Analysis of AII receptor binding in a block of tissue containing the hypothalamus, thalamus and septum (HTS) after treatment for 8 weeks with DOCA-salt (240 micrograms/kg/day) revealed a significant increase in the number of AII-binding sites compared to salt-loaded controls (Bmax 9.65 vs 6.80 fmol/mg protein) and no change in binding affinity (Kd). Significant increases in the drinking responses to peripheral (200 micrograms/kg) and central (10 ng) administration of AII were observed in these rats. Additional studies indicated that the pressor responses to either centrally (25 ng) or peripherally (20 micrograms/kg, s.c.) administered AII were augmented in DOCA-treated rats. The effect of mineralocorticoids on AII-binding sites was also investigated in primary neuronal cultures from the brains of one-day-old rats. Pretreatment of these cultures with either DOCA or aldosterone (ALDO) induced a time- and concentration-dependent increase in the specific binding of [125I]AII. Maximal increases in AII binding of 53 and 62% above control values were observed when cultures were treated with 500 pg of either ALDO or DOCA per milliliter of culture medium. Scatchard analysis of specific binding of [125I]AII in neuronal cultures treated with DOCA revealed a significant increase in Bmax but no change in Kd. Thus, mineralocorticoid hormones induce an increase in the number of AII-receptor binding sites in the HTS of rats which parallels physiological responses to both central and peripheral administration of AII. This relationship may be independent of the concentration of AII in the blood, since an increase in the number of AII binding sites was also observed in neurons cultured from the brains of one-day-old rats which had been treated with mineralocorticoid hormones.

A regulatory perspective on the potential uses of microbial risk assessment in international trade.

The recent ratification of the World Trade Organisation Agreement will arguably be the most important factor in developing new sanitary measures for the international trade in food over the next decade. There is a markedly increased desire for quantitative data on the microbial risks associated with different classes of foods, and traditional good manufacturing practice (GMP)-based food hygiene requirements are coming under increasing challenge. As the risk assessment paradigm is increasing applied and as decision-making criteria for risk management become established, more emphasis will be placed on predictive microbiology as a means of generating exposure data and establishing critical limits for Hazard Analysis Critical Control Point (HACCP) plans. In this respect, developing international guidelines for risk management arguably presents the greatest challenge in establishing and maintaining quantitative Sanitary and Phytosanitary (SP) measures for food in international trade, and for judging their equivalence. Where specific industry sectors and regulators do not have jurisdiction over the entire food chain, from production of raw materials through to consumption, it will be difficult to apply the risk assessment paradigm in the design of HACCP plans. Thus, it appears that default to food safety objectives for many segments of food production chains subject to application of HACCP plans is inevitable in the medium term.

The use of scintigraphy to demonstrate the rapid esophageal transit of the oval film-coated placebo risedronate tablet compared to a round uncoated placebo tablet when administered with minimal volumes of water.

As our population ages, and the consumption of pharmaceutical products rises, the incidence of solid oral dosage forms lodging in the esophagus is likely to increase and may be formulation dependent. The aim of this study was to compare the esophageal transit of the commercial film-coated risedronate tablet and a round uncoated tablet resembling the alendronate 10 mg tablet which is reported to cause esophagitis if ingested with little to no water. Water volumes of 30 ml and 50 ml were selected as these volumes can detect formulations prone to esophageal adhesion and a habits and practice study showed that these volumes are within the range preferred by women (7-385 ml). A total of 28 healthy postmenopausal women completed the four-way crossover scintigraphy study. For both volumes of water, the film-coated placebo risedronate tablet had a statistically significant faster esophageal transit time than the uncoated placebo tablet (P=0.002 for 30 ml water and P<0.001 for 50 ml water). Among those taking the round, flat, uncoated tablet, five subjects had esophageal stasis (transit >20 s) and in three subjects the tablet remained in the esophagus at the end of the 10-min imaging period. No stasis was observed for the oval film-coated placebo risedronate tablet. This study demonstrates that tablet size, shape and coating are pharmaceutical parameters which can be controlled to minimize esophageal contact of a dosage form with esophageal tissue.

Serological and bacteriological survey of leptospiral infection in pigs in southern England.

A total of 597 pigs were examined for serological and bacteriological evidence of leptospiral infection. The sample comprised 189 porkers, 205 baconers and 203 sows. Sera were tested against 17 antigens from 16 serogroups and the overall prevalence of titres was 15.7 per cent. The lowest prevalence of titres was found in porkers (10.0 per cent). The highest prevalence of titres to an individual antigen was recorded with bratislava, a member of the Australis serogroup, with 12.2 per cent of pigs positive. Copenhageni titres were present in 1.8 per cent of the sera and sporadic titres were recorded to various other antigens. Leptospires were isolated from five pigs. Four isolates were identified as belonging to the Icterohaemorrhagiae serogroup and one to the Hebdomadis serogroup. The serological to bacteriological ratio for the Icterohaemorrhagiae serogroup was 11:4. The virtual absence of titres to pomona and tarassovi, the two serovars most commonly maintained by porcine populations in other countries, confirms the results of earlier serological surveys.

Failure to demonstrate the maintenance of leptospires by house mice (Mus musculus) in the south east of England.

A total of 272 house mice (Mus musculus) were trapped in farm buildings at four widely separated locations of south east England and examined for serological and bacteriological evidence of leptospiral infection. Only two low titres to autumnalis antigen (1:20 and 1:40) were recorded and all mice were bacteriologically negative. The absence of leptospiral infection in the house mouse in south east England is an interesting ecological finding, as this species is a maintenance host for ballum in many countries and also a common carrier of several other serovars. The source of ballum infections in domestic stock in England remains unknown.

Leptospirosis and the maintenance host: a laboratory mouse model.

A laboratory mouse model was used to investigate the criteria that have been suggested as differentiating between a maintenance host and an accidental host for a particular leptospiral serovar. The comparative studies were conducted with serovars ballum, pomona, balcanica and hardjo. The relative pathological response, ratio of serological to bacteriological prevalence, level of serological response, age-susceptibility to infection and demonstration of artificial intraspecies transmission were found to be inadequate criteria with which to differentiate maintenance and accidental hosts for a particular serovar. The demonstration of natural intraspecies transmission was considered to be the definitive criterion for differentiating such hosts. In the light of the results obtained from the laboratory mouse model and the results obtained from field studies, a maintenance host may be defined as an animal which is capable of acting as a natural source of leptospiral infection for its own species. A maintenance population may be defined as a population of a species of animal which acts as a continuous reservoir of a serovar in a specific ecosystem.

Differentiation of reference strains of leptospires of the Pomona serogroup by cross-agglutination absorption and restriction endonuclease analysis.

The serological classification of all reference strains that have been described as representing separate serovars of Leptospira interrogans within the Pomona serogroup was investigated using cross-agglutination absorption and bacterial restriction endonuclease analysis (BRENDA). Comparative cross-agglutination absorption studies indicated that cornelli CB, monjakov Monjakov and kennewicki LT1026 were homologous with pomona Pomona, and dania K1 and tsaratsova B81/7 were homologous with mozdok 5621. BRENDA confirmed these results, except that pomona Pomona and monjakov Monjakov showed a difference in the high molecular weight region. It is proposed that four serovars be currently recognised within the Pomona serogroup: pomona, mozdok, proechimys and tropica. The relative merits of the use of cross-agglutination absorption and BRENDA with respect to identification of Pomona serogroup isolates are discussed.

Identification by cross-agglutination absorption and restriction endonuclease analysis of leptospires of the Pomona serogroup isolated in the United Kingdom.

Five strains of Leptospira interrogans isolated in the United Kingdom and belonging to the Pomona serogroup were subjected to cross-agglutination absorption and bacterial restriction endonuclease DNA analysis (BRENDA) for their identification. British isolates were compared with reference strains representing the known serovars in the Pomona serogroup and also with isolates of the Pomona serogroup obtained from other countries. Three strains isolated from wildlife in England produced equivocal results when the cross-agglutination absorption and BRENDA results were compared. According to the World Health Organisation definition of a serovar the three English strains represented two new serovars, whereas by BRENDA all three had DNA electrophoresis patterns indistinguishable from serovar mozdok. Serovar pomona has not as yet been isolated in Great Britain and the epidemiology of the Pomona serogroup infections that have been detected by serology suggests that a serovar such as mozdok, maintained by wildlife, may be the causal agent. Two strains isolated in Northern Ireland were identified as pomona by the cross-agglutination absorption test. Further studies are needed to investigate the homogeneity of field and reference strains that are designated as pomona using the cross-agglutination absorption test.

Serovar identification of leptospires of the Australis serogroup isolated from free-living and domestic species in the United Kingdom.

Eighteen isolates from the Australis serogroup from free-living and domestic animals were identified using the cross agglutination absorption test. Serovar muenchen was found only in England and Wales in wood mice, short tailed and bank voles, a grey squirrel and a pig. Serovar bratislava was found in hedgehogs in England, Wales and Northern Ireland and also in a brown rat from Northern Ireland. Serovar bratislava was isolated from sheep in both England and Northern Ireland and from horses in Northern Ireland. The distribution of these serovars in relation to possible maintenance hosts is discussed.

Risk analysis and meat hygiene.

Meat hygiene consists of three major activities: post-mortem inspection; monitoring and surveillance for chemical hazards; and maintenance of good hygienic practice throughout all stages between slaughter and consumption of meat. Risk analysis is an applied science of increasing importance to these activities in the following areas: facilitating the distribution of pre-harvest, harvest and post-harvest inspection resources, proportional to the likelihood of public health and animal health hazards; establishing internationally-harmonized standards and specifications which are consistent and science-based; and improving the safety and wholesomeness of meat and meat products in local and international trade. Risk analysis, in one form or another, is well developed with respect to establishing standards and specifications for chemical hazards; methods for risk analysis of post-mortem meat inspection programmes are beginning to emerge. However, risk analysis of microbiological hazards in meat and meat products presents particular difficulties. All areas of application currently suffer from a lack of international agreement on risk assessment and risk management methodology.

Intensive (pasture) beef cattle operations: the perspective of New Zealand.

Beef production in New Zealand has characteristics typical of a temperate climate and pasture-based animal husbandry. The specific pathogens which may contaminate fresh beef and which are empirically considered to be of public health importance are similar to those in other countries with temperate climates, i.e. Salmonella, Campylobacter, Escherichia coli O157:H7, Listeria monocytogenes and Toxoplasma gondii. With the exception of T. gondii, it is likely that almost all transmission of these hazards through consumption of beef results from unseen microbial cross-contamination from gastrointestinal sources during slaughter, dressing and further processing. Gaining comprehensive information on carcass contamination levels is an essential first step in establishing food safety objectives for a particular beef production system, and in designing risk-based hazard analysis and critical control point (HACCP) plans. It is likely that the lower mean and maximum numbers of indicator micro-organisms on New Zealand carcasses (when compared with other countries) are in part due to the pre-slaughter cleanliness status of cattle reared under temperate, pasture conditions. Similarly, the failure to detect specific pathogens of gastrointestinal origin in a comprehensive baseline survey most probably reflects the limited pathway for faecal contamination during slaughter and dressing under processing conditions in New Zealand. The New Zealand example provides strong evidence for the need to design HACCP plans according to the specific national (or regional) situation. Reducing all pathways for faecal contamination of products to the maximum extent practicable will be the most important factor in achieving desired food safety objectives for fresh beef. Variable densities of microbial pathogens in gastrointestinal contents are also likely to have a significant effect on subsequent contamination levels of beef carcasses: however, effective controls for limiting the presence of most pathogens of concern in the live animal have yet to be identified.