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Bernad-Roche M, Marín-Alcalá CM, Cebollada-Solanas A, de Blas I, Mainar-Jaime RC. Building a predictive model for assessing the risk of Salmonella shedding at slaughter in fattening pigs. Front Microbiol 2023; 14:1232490. [PMID: 37680527 PMCID: PMC10482039 DOI: 10.3389/fmicb.2023.1232490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/25/2023] [Indexed: 09/09/2023] Open
Abstract
Salmonellosis continues to be a major cause of foodborne outbreaks worldwide, and pigs are one of the main sources of human infection. Salmonella pork contamination is a major concern for abattoirs and is related to the presence of Salmonella in pigs' feces at slaughter. Being able to predict the risk of Salmonella shedding in pigs arriving at the slaughterhouse could help mitigate abattoir and carcass contamination. For this purpose, 30 batches of 50 pigs each were selected from 30 different fattening units. The pigs were tagged and bled for the detection of antibodies against Salmonella approximately one month before slaughter. Pooled floor fecal samples were also collected from 10 pens per unit for Salmonella detection, and a questionnaire on biosecurity was administered to each farm. At the abattoir, colon content was collected from each tagged pig for the Salmonella shedding assessment. A predictive model for Salmonella shedding at slaughter was built with two-third of the pigs by employing random-effects logistic regression analysis, with Salmonella shedding as the dependent variable and pig serology and other farm/environmental characteristics as the independent variables. The model included farm as the grouping factor. Data from the remaining one-third of the pigs were used for model validation. Out of 1,500 pigs initially selected, 1,341 were identified at the abattoir and analyzed. Salmonella was detected in 13 (43.3%; 95%CI = 27.4-60.8) of the fattening units. The mean batch seroprevalence (cut-off OD% ≥40) among the fattening units was 31.7% (95%CI = 21.8-41.0), and a total of 316 pigs (23.6%; 95%CI = 21.4-25.9) shed Salmonella at slaughter. The model predicted reasonably well (Area under the curve = 0.76; P < 0.05) whether a pig would shed Salmonella at slaughter, with estimates of sensitivity and specificity at 71.6% and 73.6%, respectively. Serology, the percentage of Salmonella-positive pens on the farm, and the internal biosecurity score were significantly associated (P < 0.05) with Salmonella shedding at the abattoir, and several scenarios were observed by the model. The study highlighted that although serology may be helpful for identifying batches of pigs at risk of shedding Salmonella upon their arrival at the abattoir, it may not be necessary in some scenarios.
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Affiliation(s)
- María Bernad-Roche
- Departamento de Patología Animal, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, Zaragoza, Spain
| | - Clara María Marín-Alcalá
- Departamento de Ciencia Animal, Centro de Investigación y Tecnología Agroalimentaria de Aragón, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, Zaragoza, Spain
| | - Alberto Cebollada-Solanas
- Unidad de Biocomputación, Instituto Aragonés de Ciencias de la Salud (IACS/IIS Aragón), Centro de Investigación Biomédica de Aragón (CIBA), Zaragoza, Spain
| | - Ignacio de Blas
- Departamento de Patología Animal, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, Zaragoza, Spain
| | - Raúl Carlos Mainar-Jaime
- Departamento de Patología Animal, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, Zaragoza, Spain
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Bernad-Roche M, Casanova-Higes A, Marín-Alcalá CM, Mainar-Jaime RC. Salmonella Shedding in Slaughter Pigs and the Use of Esterified Formic Acid in the Drinking Water as a Potential Abattoir-Based Mitigation Measure. Animals (Basel) 2022; 12:ani12131620. [PMID: 35804519 PMCID: PMC9264893 DOI: 10.3390/ani12131620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/07/2022] [Accepted: 06/21/2022] [Indexed: 11/16/2022] Open
Abstract
Pigs shedding Salmonella at slaughter are considered a source of carcass contamination and human infection. To assess this potential risk, the proportion of Salmonella shedders that arrive for slaughter was evaluated in a population of 1068 pigs from 24 farms. Shedding was present in 27.3% of the pigs, and the monophasic variant of Salmonella Typhimurium, an emerging zoonotic serotype, was the most prevalent (46.9%). Antimicrobial resistance (AMR) in Salmonella isolates was common, but few isolates showed AMR to antimicrobials of critical importance for humans such as third-generation cephalosporins (5%), colistin (0%), or carbapenems (0%). However, AMR to tigecycline was moderately high (15%). The efficacy of an esterified formic acid in the lairage drinking water (3 kg formic acid/1000 L) was also assessed as a potential abattoir-based strategy to reduce Salmonella shedding. It was able to reduce the proportion of shedders (60.7% in the control group (CG) vs. 44.3% in the treatment group (TG); p < 0.01). After considering clustering and confounding factors, the odds of shedding Salmonella in the CG were 2.75 (95% CI = 1.80−4.21) times higher than those of the TG, suggesting a potential efficacy of reduction in shedding as high as 63.6%. This strategy may contribute to mitigating the burden of abattoir environmental contamination.
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Affiliation(s)
- María Bernad-Roche
- Departamento de Patología Animal, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, 50013 Zaragoza, Spain; (M.B.-R.); (A.C.-H.)
| | - Alejandro Casanova-Higes
- Departamento de Patología Animal, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, 50013 Zaragoza, Spain; (M.B.-R.); (A.C.-H.)
| | - Clara María Marín-Alcalá
- Departamento de Ciencia Animal, Centro de Investigación y Tecnología Agroalimentaria de Aragón, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, 50059 Zaragoza, Spain;
| | - Raúl Carlos Mainar-Jaime
- Departamento de Patología Animal, Facultad de Veterinaria, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, 50013 Zaragoza, Spain; (M.B.-R.); (A.C.-H.)
- Correspondence: ; Tel.: +34-976-762-088
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De Lucia A, Cawthraw SA, Smith RP, Davies R, Bianco C, Ostanello F, Martelli F. Pilot Investigation of Anti- Salmonella Antibodies in Oral Fluids from Salmonella Typhimurium Vaccinated and Unvaccinated Swine Herds. Animals (Basel) 2021; 11:ani11082408. [PMID: 34438865 PMCID: PMC8388757 DOI: 10.3390/ani11082408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/01/2021] [Accepted: 08/12/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary The consumption of pork meat is responsible for a significant number of outbreaks of salmonellosis in people. Surveillance in pig herds is constrained by the cost-effectiveness and efficiency of sampling methods. The last decade has seen significant advances in the routine use of pool samples, including oral fluids (OFs). This study aimed to investigate the OF collected passively via chewed sampling ropes as a potential sample type for assessing anti-Salmonella antibodies in two Salmonella-vaccinated (V) and two non-vaccinated (NV) farrow-to-finish pig farms, comparing the results with the Salmonella shedding of tested animals. Sows in the V farms were vaccinated prior to farrowing. Pooled faecal and OF samples were collected from sows and their offspring. Salmonella was isolated with direct bacteriological methods. A commercial ELISA assay was adapted to detect IgG and IgA antibodies in OF. Overall, a higher Salmonella prevalence was observed in the NV farm and in the offspring (76.3%) compared to sows (36.4%). The protocol used to test anti-Salmonella IgA in pig OF samples was found to lack sensitivity and specificity. At herd level, IgG is the most reliable isotype for monitoring Salmonella specific antibody via OF. Abstract Oral fluid (OF) can be a simple, cheap and non-invasive alternative to serum or meat juice for the diagnosis and surveillance of important pathogens in pigs. This study was conducted on four Salmonella Typhimurium-positive farrow-to-finish pig farms: two Salmonella-vaccinated (V) and two non-vaccinated (NV). Gilts and sows in the V farms were vaccinated with a live, attenuated vaccine prior to farrowing. Pooled faecal and OF samples were collected from the sows and their offspring. Salmonella was isolated according to ISO6579–1:2017. In parallel, IgG and IgA levels were assessed in OF samples using a commercial ELISA assay. Salmonella was detected in 90.9% of the pooled faecal samples from the NV farms and in 35.1% of the pooled faecal samples from the V farms. Overall, a higher prevalence was observed in the pooled faecal samples from the offspring (76.3%) compared to the sows (36.4%). IgG antibodies measured in V farms are likely to be related to vaccination, as well as exposure to Salmonella field strains. The detection of IgA antibodies in OF was unreliable with the method used. The results of this study show that IgG is the most reliable isotype for monitoring Salmonella-specific antibody immunity in vaccinated/infected animals via OF.
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Affiliation(s)
- Alessia De Lucia
- Department of Veterinary Medical Sciences, School of Agriculture and Veterinary Medicine, via Tolara di Sopra 50, 40064 Ozzano Emilia, Italy;
| | - Shaun A. Cawthraw
- Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone KT15 3NB, UK; (S.A.C.); (R.P.S.); (R.D.); (F.M.)
| | - Richard Piers Smith
- Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone KT15 3NB, UK; (S.A.C.); (R.P.S.); (R.D.); (F.M.)
| | - Rob Davies
- Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone KT15 3NB, UK; (S.A.C.); (R.P.S.); (R.D.); (F.M.)
| | - Carlo Bianco
- Animal and Plant Health Agency Lasswade, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, UK;
| | - Fabio Ostanello
- Department of Veterinary Medical Sciences, School of Agriculture and Veterinary Medicine, via Tolara di Sopra 50, 40064 Ozzano Emilia, Italy;
- Correspondence:
| | - Francesca Martelli
- Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone KT15 3NB, UK; (S.A.C.); (R.P.S.); (R.D.); (F.M.)
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van der Wolf P, Meijerink M, Libbrecht E, Tacken G, Gijsen E, Lillie-Jaschniski K, Schüller V. Salmonella Typhimurium environmental reduction in a farrow-to-finish pig herd using a live attenuated Salmonella Typhimurium vaccine. Porcine Health Manag 2021; 7:43. [PMID: 34301340 PMCID: PMC8299633 DOI: 10.1186/s40813-021-00222-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 07/03/2021] [Indexed: 01/27/2023] Open
Abstract
Background Salmonella Typhimurium is an important zoonotic pathogen in pigs, that can cause clinical disease. Many sow herds and finishing herds are infected with Salmonella, and therefore pose a threat for the contamination of pork and pork products and ultimately consumers. Case presentation This case study describes a farrow-to-finish pig herd, producing its own replacement gilts, which had experienced clinical outbreaks of salmonellosis since 2002. Outbreaks were characterised by profuse diarrhoea, dead pigs and high antimicrobial use (colistin sulphate). The aim of this study was to see whether using vaccination of sows and piglets with Salmoporc®, a live attenuated Salmonella Typhimurium vaccine, in combination with standard hygienic precautions, it was possible to reduce Salmonella Typhimurium to below the bacteriological detection limit. Monitoring of the presence of Salmonella was done using a total of 20 pooled faecal, sock and dust samples per herd visit in the period from September 2016 to October 2020. Within the first 10 months after the start of vaccination in August 2016, there was a rapid reduction in clinical symptoms, antimicrobial usage and the number of Salmonella-positive samples. During the winters of 2017/2018 and 2018/2019 the number of positive samples increased again, however with minimal need to use antimicrobials to treat the affected animals. In July 2019, only two samples from a corridor were positive. In September and November 2019 and in October 2020 all three samplings were completely negative for S. Typhimurium. Conclusions This case, together with other longitudinal studies, can be seen as a proof of the principle that long term vaccination with a live attenuated S. Typhimurium vaccine can reduce the level of S. Typhimurium in the herd environment to very low levels within a farrow-to-finish herd initially suffering from clinical salmonellosis. Also, clinical symptoms indicating salmonellosis were no longer observed and antimicrobials to treat clinically diseased pigs were no longer needed.
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Affiliation(s)
| | | | | | - Gerrit Tacken
- Veterinary Practice "VarkensArtsenZuid", Panningen, The Netherlands
| | - Emile Gijsen
- Veterinary Practice "VarkensArtsenZuid", Panningen, The Netherlands
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Modernization of Control of Pathogenic Micro-Organisms in the Food-Chain Requires a Durable Role for Immunoaffinity-Based Detection Methodology-A Review. Foods 2021; 10:foods10040832. [PMID: 33920486 PMCID: PMC8069916 DOI: 10.3390/foods10040832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/28/2021] [Accepted: 04/02/2021] [Indexed: 01/03/2023] Open
Abstract
Food microbiology is deluged by a vastly growing plethora of analytical methods. This review endeavors to color the context into which methodology has to fit and underlines the importance of sampling and sample treatment. The context is that the highest risk of food contamination is through the animal and human fecal route with a majority of foodborne infections originating from sources in mass and domestic kitchens at the end of the food-chain. Containment requires easy-to-use, failsafe, single-use tests giving an overall risk score in situ. Conversely, progressive food-safety systems are relying increasingly on early assessment of batches and groups involving risk-based sampling, monitoring environment and herd/flock health status, and (historic) food-chain information. Accordingly, responsible field laboratories prefer specificity, multi-analyte, and high-throughput procedures. Under certain etiological and epidemiological circumstances, indirect antigen immunoaffinity assays outperform the diagnostic sensitivity and diagnostic specificity of e.g., nucleic acid sequence-based assays. The current bulk of testing involves therefore ante- and post-mortem probing of humoral response to several pathogens. In this review, the inclusion of immunoglobulins against additional invasive micro-organisms indicating the level of hygiene and ergo public health risks in tests is advocated. Immunomagnetic separation, immunochromatography, immunosensor, microsphere array, lab-on-a-chip/disc platforms increasingly in combination with nanotechnologies, are discussed. The heuristic development of portable and ambulant microfluidic devices is intriguing and promising. Tant pis, many new platforms seem unattainable as the industry standard. Comparability of results with those of reference methods hinders the implementation of new technologies. Whatever the scientific and technological excellence and incentives, the decision-maker determines this implementation after weighing mainly costs and business risks.
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Viana C, Sereno MJ, Bersot LDS, Kich JD, Nero LA. Comparison of Meat Juice Serology and Bacteriology for Surveillance of Salmonella in the Brazilian Pork Production Chain. Foodborne Pathog Dis 2020; 17:194-201. [DOI: 10.1089/fpd.2019.2712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Cibeli Viana
- Departamento de Veterinária, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Mallu Jagnow Sereno
- Departamento de Veterinária, Universidade Federal de Viçosa, Viçosa, MG, Brazil
- Universidade Federal do Paraná - Setor Palotina, Departamento de Ciências Veterinárias, Palotina, PR, Brazil
| | - Luciano dos Santos Bersot
- Universidade Federal do Paraná - Setor Palotina, Departamento de Ciências Veterinárias, Palotina, PR, Brazil
| | | | - Luís Augusto Nero
- Departamento de Veterinária, Universidade Federal de Viçosa, Viçosa, MG, Brazil
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De Lucia A, Cawthraw S, Davies R, Smith RP, Bianco C, Ostanello F, Martelli F. Correlation of Anti- Salmonella Antibodies Between Serum and Saliva Samples Collected From Finisher Pigs. Front Vet Sci 2020; 6:489. [PMID: 31998766 PMCID: PMC6967412 DOI: 10.3389/fvets.2019.00489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/10/2019] [Indexed: 11/30/2022] Open
Abstract
Saliva samples obtained by using absorptive devices, can provide an alternative diagnostic matrix to serum for monitoring disease status in pigs. The aim of this study was to investigate the correlation of anti-Salmonella antibodies between serum and saliva samples collected from pigs. Twenty individual paired serum and saliva samples were collected from a single farm. Anti-Salmonella IgG was detected in individual serum samples using a commercial Salmonella ELISA kit, validated for sera. The same kit was used with a protocol modified by extending incubation time and increasing temperature to test individual saliva samples. Anti-Salmonella IgG antibodies in pig saliva were always detected at a lower level than in the matching serum samples. A correlation (rho = 0.66; p = 0.002) and a moderate agreement (K > 0.62 p = 0.003) was found between individual Salmonella IgG in serum and saliva samples. Both correlation and the agreement levels are moderate. The size of this investigation was small, and further studies are necessary to further confirm these findings. The results of this work provide some evidence that saliva samples have the potential to be used for the diagnosis of Salmonella infection in pig farms.
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Affiliation(s)
- Alessia De Lucia
- Department of Veterinary Medical Sciences, School of Agriculture and Veterinary Medicine, Bologna, Italy
- Animal and Plant Health Agency (APHA), Bacteriology Department, Addlestone, United Kingdom
| | - Shaun Cawthraw
- Animal and Plant Health Agency (APHA), Bacteriology Department, Addlestone, United Kingdom
| | - Rob Davies
- Animal and Plant Health Agency (APHA), Bacteriology Department, Addlestone, United Kingdom
| | - Richard P. Smith
- Animal and Plant Health Agency (APHA), Epidemiology Department, Addlestone, United Kingdom
| | - Carlo Bianco
- Animal and Plant Health Agency (APHA), Pathology Department, Addlestone, United Kingdom
| | - Fabio Ostanello
- Department of Veterinary Medical Sciences, School of Agriculture and Veterinary Medicine, Bologna, Italy
| | - Francesca Martelli
- Animal and Plant Health Agency (APHA), Bacteriology Department, Addlestone, United Kingdom
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Cevallos-Almeida M, Fablet C, Houdayer C, Dorenlor V, Eono F, Denis M, Kerouanton A. Longitudinal study describing time to Salmonella seroconversion in piglets on three farrow-to-finish farms. Vet Rec Open 2019; 6:e000287. [PMID: 31673373 PMCID: PMC6802978 DOI: 10.1136/vetreco-2018-000287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 09/10/2019] [Accepted: 09/11/2019] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Pigs are frequently colonised with Salmonella enterica, and this constitutes a major risk for human salmonellosis. The infection can be assessed by the serological response of pigs to S enterica. A longitudinal study was undertaken on-farm to correctly describe this serological response and investigate factors associated with age at Salmonella seroconversion. METHODS Three pig farms and in each farm three successive batches were considered. Per batch, 40 piglets were selected at random from 10 sows (four piglets per sow). Blood was sampled from sows one week after farrowing and from piglets at weeks 1, 6, 10, 14, 18 and 22 and at the slaughterhouse. Salmonella antibodies were detected in serum using a commercial ELISA test. Factors related to farm characteristics, batch management system, porcine reproductive and respiratory syndrome infection, and sows' Salmonella serological status were recorded to assess their effect on age at seroconversion. RESULTS At week 1 after farrowing, 96.5 per cent of the sows had antibodies against Salmonella. The serological results of piglets at weeks 1 and 6 only were positively correlated with those of the sows. The average age at Salmonella seroconversion was 137±2.2 days (confidence interval at 95 per cent). The first seroconversions occurred from weeks 10 to 14, but most of the pigs (54.6 per cent) were seropositive at the end of the fattening period, with variations between farms and batches (28.9-75.7 per cent). Herd/farm was significantly associated with age at seroconversion. CONCLUSION This longitudinal study allowed the authors to follow precisely the evolution of Salmonella seroconversion from maternity to slaughterhouse and confirm the relationship between the seroconversion of sows and serology of their piglets. Moreover, factors related to farm practices and management as a whole are more influential than individual factors (at the pig level) on age at Salmonella seroconversion.
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Affiliation(s)
- Maria Cevallos-Almeida
- ANSES, Ploufragan-Plouzané-Niort Laboratory, Hygiene and Quality of Poultry and Pig Products Unit, Ploufragan, France
- Facultad Medicina Veterinaria y Zootecnia, Universidad Central del Ecuador, Quito, Ecuador
| | - Christelle Fablet
- ANSES, Ploufragan-Plouzané-Niort Laboratory, Hygiene and Quality of Poultry and Pig Products Unit, Ploufragan, France
- ANSES, Ploufragan-Plouzané-Niort Laboratory, Epidemiology, Health and Welfare research unit, Ploufragan, France
| | - Catherine Houdayer
- ANSES, Ploufragan-Plouzané-Niort Laboratory, Hygiene and Quality of Poultry and Pig Products Unit, Ploufragan, France
| | - Virginie Dorenlor
- ANSES, Ploufragan-Plouzané-Niort Laboratory, Epidemiology, Health and Welfare research unit, Ploufragan, France
| | - Florent Eono
- ANSES, Ploufragan-Plouzané-Niort Laboratory, Epidemiology, Health and Welfare research unit, Ploufragan, France
| | - Martine Denis
- ANSES, Ploufragan-Plouzané-Niort Laboratory, Hygiene and Quality of Poultry and Pig Products Unit, Ploufragan, France
| | - Annaëlle Kerouanton
- ANSES, Ploufragan-Plouzané-Niort Laboratory, Hygiene and Quality of Poultry and Pig Products Unit, Ploufragan, France
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Schut CH, Farzan A, Ainslie-Garcia MH, Friendship RM, Lillie BN. Antibody Responses to Salmonella in Pigs from Weaning Up to Marketing and Presence of Salmonella at Slaughter. Foodborne Pathog Dis 2018; 16:187-194. [PMID: 30481060 DOI: 10.1089/fpd.2018.2454] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Salmonella is estimated to be one of the leading causes of enteric illness worldwide. Human salmonellosis is most frequently related to contaminated food products, particularly those of animal origin, such as pork. Pigs are often asymptomatic carriers of Salmonella, highlighting the importance of identifying high-prevalence farms and effective detection methods. The objectives of this study were to investigate Salmonella antibody responses and their association with on-farm shedding and Salmonella isolation at slaughter. Fourteen groups of pigs from eight farrowing sources were followed from birth to slaughter (totaling 796 pigs). Information about farm management was collected through a questionnaire. Blood and fecal samples were collected four times at different stages of production, and palatine tonsils/submandibular lymph nodes were obtained at slaughter. Sera were tested for Salmonella antibodies by enzyme-linked immunosorbent assay, and fecal/tissue samples were cultured for Salmonella. Data were analyzed using a mixed-effect multivariable modeling method with farm, litter, and pig as random effects. Salmonella seropositivity rates were 20.3%, 5.8%, 15.9%, and 37.3% at weaning, at the end of nursery, at end of grower, and at end of finisher, respectively. Salmonella seropositivity and shedding increased with age (p < 0.05), and pigs shedding Salmonella were more likely to test seropositive (p = 0.02). Antibody response and shedding on-farm had no significant association with isolation of Salmonella from tissues harvested at slaughter. The variation in Salmonella seropositivity due to farm was 28.9% of total variation. These findings indicate that on-farm intervention may be a more effective approach to control Salmonella and to reduce the presence of Salmonella at slaughter. Additionally, the observation that some pigs in this study were Salmonella-negative throughout production and at slaughter is promising with regard to food safety, and studies are needed to explore the genotypes of those pigs.
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Affiliation(s)
- Corinne H Schut
- 1 Department of Pathobiology and University of Guelph , Guelph, Canada
| | - Abdolvahab Farzan
- 1 Department of Pathobiology and University of Guelph , Guelph, Canada .,2 Department of Population Medicine, University of Guelph , Guelph, Canada
| | | | | | - Brandon N Lillie
- 1 Department of Pathobiology and University of Guelph , Guelph, Canada
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Felin E, Hälli O, Heinonen M, Jukola E, Fredriksson-Ahomaa M. Assessment of the feasibility of serological monitoring and on-farm information about health status for the future meat inspection of fattening pigs. Prev Vet Med 2018; 162:76-82. [PMID: 30621901 DOI: 10.1016/j.prevetmed.2018.11.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 11/17/2018] [Accepted: 11/18/2018] [Indexed: 11/18/2022]
Abstract
Current macroscopic meat inspection cannot detect the most common pork-borne pathogens (Salmonella spp., Yersinia enterocolitica and Toxoplasma gondii). Furthermore, food chain information (FCI) may not provide sufficient data for visual-only inspection, which is supposed to be the common way of inspection of pigs in the European Union. Our observational study aimed to evaluate the serological monitoring and the clinical evaluation of on-farm health status of pigs and assess the feasibility of these data as part of the FCI in meat inspection. We studied the serological status of Salmonella spp., Yersinia spp. and T. gondii in pigs during the fattening period. Additionally, we evaluated the association between on-farm health status and meat inspection findings. On 57 indoor fattening pig farms in Finland, we collected blood samples (mean of 20 pigs/farm) and assessed the on-farm health (coughing, tail biting, lameness) at the end of the fattening period. We visited 34 of these farms also at the beginning of the fattening for sampling and on-farm health evaluation of the same pigs. Meat inspection results were obtained after slaughter for all 57 farms. Salmonella seroprevalence was low at the end of the fattening period: it was 17.6%, 10.6% or 1.9%, with the cut-off values of OD15% (recommended by the test manufacturer), OD20% (used by Danish monitoring programme) and OD40% (used by German monitoring programme), respectively. The overall seroprevalence of Salmonella spp. and Yersinia spp. increased significantly (P < 0.001) during the fattening period (from 8.1% to 17.2% and from 30.3% to 72.3%, respectively), while the seroprevalence of T. gondii remained low (<1%). The within-farm seroprevalences of Salmonella spp. and Yersinia spp. differed significantly between the farms and this farm-level serological data could be used as FCI for risk-based decisions to improve food safety. Such potentially feasible decisions could include additional carcass testing, carcass decontamination, carcass processing, slaughtering arrangements and improved biosecurity measures at the farm. However, risk mitigation targets and procedures must be carefully adjusted for each pathogen regarding also economic aspects. Tail biting observed on farm was associated with partial carcass condemnations and arthritis at slaughter. This information could be included in the FCI and used when making decisions regarding meat inspection procedure: visual-only or additional inspections.
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Affiliation(s)
- Elina Felin
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O Box 66, 00014, University of Helsinki, Finland.
| | - Outi Hälli
- Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920 SAARENTAUS, Finland.
| | - Mari Heinonen
- Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920 SAARENTAUS, Finland.
| | - Elias Jukola
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O Box 66, 00014, University of Helsinki, Finland.
| | - Maria Fredriksson-Ahomaa
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O Box 66, 00014, University of Helsinki, Finland.
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