Origin of Listeria monocytogenes on meat products

Listeria monocytogenes is a relevant food safety hazard in ready to eat products. Inactivation during processing, prevention of recontamination and control of multiplication are the main instruments to secure the safety of meat products. Intensive microbiological monitoring of products and the production environment are valuable tools to assess the level of control in a meat processing plant. During the course of a year all isolates found during hygiene monitoring at a meat processing plant were stored at -70 degrees Celsius. A total of 94 L. monocytogenes isolates have been analyzed by pulsed-field gel electrophoresis (PFGE) and were divided into 30 different types

Experiences with a risk based meat inspection standard in pigs

The European Union legislation provides several possibilities to modernize meat inspection. Improvement of food safety by active contribution of food business operators in the supply chain being responsible for food safety is envisaged in these new standards

Case study: Tuberculination, serology and bacteriology of sows at a farrowing unit suspected of an infection with Mycobacterium avium

Mycobacterium avium (MA) is considered a zoonotic hazard in pork. Herds delivered at slaughter showing gross lesions indicative of a mycobacterial infection, eg. specific abcesses in lymphoreticular tissue, were bacteriologically positive for MA. A risk factor analysis revealing different possible sources of primary infection was carried out at farms supplying these pigs. Also the common farrowing farm supplying the piglets to these farms was taken into account as a possible source of infection. Intradermal tuberculin testing, serology and tissue sampling was carried out on the sows and finishing pigs

Using serological monitoring, internet-based feedback and on-farm auditing to improve Toxoplasma gondii control at Dutch pig farms

Toxoplasma gondii is a relevant foodborne pathogen due to its human disease burden. In the Netherlands, pork is estimated to contribute to 11% of the meatborne T. gondii infections. The European Food Safety Authority advised to perform serological testing of pigs and on farm audits on risk factors for T. gondii infection

Withdrawal periods after treatment of pigs with oxytetracycline in- and outside the European Union

Withdrawal periods are used to avoid animals being delivered to slaughter before the concentration of the antimicrobial has declined to values below the maximum residue limit (MRL). This paper characterises the withdrawal periods in force for oxytetracycline 100 mg/ml for intramuscular use in pigs. We investigated the variation in duration of the withdrawal period between 68 oxytetracycline products from 29 countries in- and outside the European Union. More specifically, we tested whether there is a regional difference, a difference between major and minor pig meat exporting countries, whether the product is long-acting or not, and whether year of market authorisation correlated with the withdrawal period. The results showed a large variation in duration of the withdrawal periods, ranging from 5 to 40 days. Variation was observed both between and within countries. Moreover, major exporting countries were associated with a longer withdrawal period than minor exporting countries (P = 0.00099). There were no regional differences, and the year of market authorisation had no impact, but long-acting products had a shorter withdrawal period than short-acting products (P = 0.048). The variation in withdrawal periods observed questions the utility of using compliance with the withdrawal period as a means of assessing whether the meat is safe for consumption. This is particularly relevant when a pig producer unintentionally delivers pigs for slaughter before the withdrawal period has expired and, aware of this, informs the abattoir. The findings call for further harmonisation in determining the withdrawal periods for all veterinary medicinal products (VMP). Until this happens, if animals are prematurely sent to slaughter, we suggest that the concentration of the VMP at the time of slaughter is calculated and compared with the MRL to determine meat safety

Origin of Listeria monocytogenes on meat products

Listeria monocytogenes is a relevant food safety hazard in ready to eat products. Inactivation during processing, prevention of recontamination and control of multiplication are the main instruments to secure the safety of meat products. Intensive microbiological monitoring of products and the production environment are valuable tools to assess the level of control in a meat processing plant. During the course of a year all isolates found during hygiene monitoring at a meat processing plant were stored at -70 degrees Celsius. A total of 94 L. monocytogenes isolates have been analyzed by pulsed-field gel electrophoresis (PFGE) and were divided into 30 different types.</p

Improving antimicrobial residue surveillance in finishing pigs by risk-based sampling designs

EU Member States are obliged by legislation to implement residue surveillance programs to detect illegal use or misuse of veterinary medicines in food producing animals and investigate the reasons for residue violations. According to EU legislation, these programs should be (partly) risk-based, meaning targeted towards groups of animals, where the probability of finding residues is the highest. There is however no default surveillance procedure describing the most efficient way to do so. In this study, a quantitative analysis was conducted to quantify the effectiveness of detecting antimicrobial residues in finishing pigs via risk-based sampling of carcasses. A stochastic scenario tree analysis was applied to estimate the sensitivity of random and risk-based sampling strategies to detect a contaminated carcass. In these models, the probability was calculated that a single carcass will yield a positive outcome when subjected to the testing protocol laid down in the design, given that contamination with antimicrobial residues is prevalent in the herd of origin at the level of the design prevalence. Two design prevalences were used: 0.01% (the assumed true prevalence of residue-positive carcasses) and 0.22% (the prevalence that can be detected using the sample size laid down in EU legislation). In the random design, it was assumed that the carcasses examined for presence of antimicrobial residues were selected randomly from all finishing pigs slaughtered in a year. In the risk-based design, two risk factors were taken into account. First, a high prevalence of chronic pleuritis and pneumonia in the herd of origin was assessed. Secondly, the route of administration of antimicrobials (oral/parenteral) via visual inspection of skin lesions indicative of injectables was used as an additional risk factor. Results showed that the probability of detecting a residue-positive carcass doubled when surveillance was targeted at pigs originating from herds with a high prevalence of chronic pleuritis and pneumonia (compared to random sampling), at similar costs of testing. Including administration route as an additional risk factor led to a negligible increase in sensitivity. Nevertheless, sensitivity values at unit level remained extremely low due to the very low prevalence of antimicrobial residues in pigs. In this study, risk-based alternatives to random sampling improved the cost-effectiveness of residue surveillance in slaughter pigs in the Netherlands, which could be used to enhance current programs and to increase awareness in food business operators

Experiences with a risk based meat inspection standard in pigs

The European Union legislation provides several possibilities to modernize meat inspection. Improvement of food safety by active contribution of food business operators in the supply chain being responsible for food safety is envisaged in these new standards.</p

Improving antimicrobial residue surveillance in finishing pigs by risk-based sampling designs

EU Member States are obliged by legislation to implement residue surveillance programs to detect illegal use or misuse of veterinary medicines in food producing animals and investigate the reasons for residue violations. According to EU legislation, these programs should be (partly) risk-based, meaning targeted towards groups of animals, where the probability of finding residues is the highest. There is however no default surveillance procedure describing the most efficient way to do so. In this study, a quantitative analysis was conducted to quantify the effectiveness of detecting antimicrobial residues in finishing pigs via risk-based sampling of carcasses. A stochastic scenario tree analysis was applied to estimate the sensitivity of random and risk-based sampling strategies to detect a contaminated carcass. In these models, the probability was calculated that a single carcass will yield a positive outcome when subjected to the testing protocol laid down in the design, given that contamination with antimicrobial residues is prevalent in the herd of origin at the level of the design prevalence. Two design prevalences were used: 0.01% (the assumed true prevalence of residue-positive carcasses) and 0.22% (the prevalence that can be detected using the sample size laid down in EU legislation). In the random design, it was assumed that the carcasses examined for presence of antimicrobial residues were selected randomly from all finishing pigs slaughtered in a year. In the risk-based design, two risk factors were taken into account. First, a high prevalence of chronic pleuritis and pneumonia in the herd of origin was assessed. Secondly, the route of administration of antimicrobials (oral/parenteral) via visual inspection of skin lesions indicative of injectables was used as an additional risk factor. Results showed that the probability of detecting a residue-positive carcass doubled when surveillance was targeted at pigs originating from herds with a high prevalence of chronic pleuritis and pneumonia (compared to random sampling), at similar costs of testing. Including administration route as an additional risk factor led to a negligible increase in sensitivity. Nevertheless, sensitivity values at unit level remained extremely low due to the very low prevalence of antimicrobial residues in pigs. In this study, risk-based alternatives to random sampling improved the cost-effectiveness of residue surveillance in slaughter pigs in the Netherlands, which could be used to enhance current programs and to increase awareness in food business operators

Case study: Tuberculination, serology and bacteriology of sows at a farrowing unit suspected of an infection with Mycobacterium avium

Mycobacterium avium (MA) is considered a zoonotic hazard in pork. Herds delivered at slaughter showing gross lesions indicative of a mycobacterial infection, eg. specific abcesses in lymphoreticular tissue, were bacteriologically positive for MA. A risk factor analysis revealing different possible sources of primary infection was carried out at farms supplying these pigs. Also the common farrowing farm supplying the piglets to these farms was taken into account as a possible source of infection. Intradermal tuberculin testing, serology and tissue sampling was carried out on the sows and finishing pigs.</p