The microbiological and sensory status of dual-purpose chickens (Lohmann Dual), male Lohmann Brown Plus chickens, and conventional laying hens slaughtered in a laying hen abattoir compared to conventional broilers slaughtered in a broiler abattoir.

Alternatives to conventional chicken meat and egg production are increasingly under discussion, especially because of the common practice of killing male day-old chicks from laying lines which has been banned from the beginning of 2022 in Germany and is planned to be banned during 2022 in other countries. Production of dual-purpose chicken lines is one possible solution, as such lines combine moderate laying and growth performance. The microbiological status of products from such breeds must be comparable to existing products on the market for food safety purposes. Additionally, the production of such products will take longer because of the feeding regimes required, and again, comparability should be safeguarded for the best consumer protection. The dual-purpose chicken line, Lohmann Dual (males), was compared to males from the laying line Lohmann Brown Plus, conventional laying hens (all slaughtered and processed in the same conventional laying hen abattoir), and conventional broilers (slaughtered in a conventional broiler abattoir). Neck skin samples were taken before chilling at the end of each slaughter line to determine the microbial status of the carcasses. Additionally, fresh and cooked meat sensory analysis was performed on meat from broilers and male and female Lohmann Dual and Lohmann Brown Plus chickens (for three carcasses of each group) at the German Agricultural Society Test Center in Kassel. The focus was on the performance of male Lohmann Dual compared to the other lines. There was no difference in the Enterobacteriaceae count of the dual-purpose chicken line compared to conventional broilers, whereas laying hens had a significantly higher microbial load before chilling, as based on neck skin examinations (p<0.001). According to sensory test results, the meat from dual-purpose chickens was the best (as no defects were found) among the five chicken meat types examined. In conclusion, based on their microbial status and sensory analysis of fresh and cooked meat, Lohmann Dual males slaughtered in a laying hen abattoir can be considered as an alternative to conventionally kept broilers slaughtered in a broiler abattoir.

A European-wide dataset to uncover adaptive traits of Listeria monocytogenes to diverse ecological niches.

Listeria monocytogenes (Lm) is a ubiquitous bacterium that causes listeriosis, a serious foodborne illness. In the nature-to-human transmission route, Lm can prosper in various ecological niches. Soil and decaying organic matter are its primary reservoirs. Certain clonal complexes (CCs) are over-represented in food production and represent a challenge to food safety. To gain new understanding of Lm adaptation mechanisms in food, the genetic background of strains found in animals and environment should be investigated in comparison to that of food strains. Twenty-one partners, including food, environment, veterinary and public health laboratories, constructed a dataset of 1484 genomes originating from Lm strains collected in 19 European countries. This dataset encompasses a large number of CCs occurring worldwide, covers many diverse habitats and is balanced between ecological compartments and geographic regions. The dataset presented here will contribute to improve our understanding of Lm ecology and should aid in the surveillance of Lm. This dataset provides a basis for the discovery of the genetic traits underlying Lm adaptation to different ecological niches.

Distribution and Characteristics of Listeria spp. in Pigs and Pork Production Chains in Germany.

Listeria (L.) monocytogenes is a foodborne pathogen that can cause disease, mainly in elderly, pregnant or immunocompromised persons through consumption of contaminated food, including pork products. It is widespread in the environment and can also be found in asymptomatic carrier animals, for example, in different tissues of pigs. To learn more about their nature, 16 Listeria spp. isolates found in tonsils and intestinal content of pigs and 13 isolates from the slaughterhouse environment were characterized using next-generation sequencing (NGS). A wide distribution of clonal complexes was observed in pigs, as well as in the pork production chain, suggesting multiple sources of entry. Hypervirulent clones were found in pig tonsils, showing the potential risk of pigs as source of isolates causing human disease. The presence of closely related isolates along the production chain suggests a cross-contamination in the slaughterhouse or recontamination from the same source, strengthening the importance of efficient cleaning and disinfection procedures. The phenotypical antimicrobial resistance status of L. monocytogenes isolates was examined via broth microdilution and revealed a low resistance level. Nevertheless, genotypical resistance data suggested multiple resistances in some non-pathogenic L. innocua isolates from pig samples, which might pose a risk of spreading resistances to pathogenic species.

High Predictive Power of Meat Juice Serology on the Presence of Hepatitis E Virus in Slaughter Pigs.

Hepatitis E virus (HEV) as a zoonotic agent can be responsible for an acute hepatitis in humans, which is usually self-limiting. Progression toward a chronic stage is possible, especially in immunocompromised patients. In the past decade, the number of hepatitis E cases in humans in Germany has increased enormously to 3491 cases in 2018. Domestic pigs have been identified as a main animal reservoir and the consumption of raw and undercooked pork products, that is, livers or liver products, meat or meat products, is known as a potential risk of foodborne HEV infection. The aim of this study was to determine whether serological tests are appropriate to predict the occurrence of HEV in the liver and muscle of domestic pigs in Germany. In 2018, samples of meat juice, liver, and ham muscle were collected from 250 fattening pigs at an abattoir in North West Germany. Samples were analyzed for the presence of HEV antibodies using enzyme-linked immunosorbent assay respectively for the presence of HEV RNA using real-time reverse transcription-polymerase chain reaction. In total, 62% (155/250) of the meat juice samples were positive for HEV antibodies at a single animal basis. At herd level, 72% (18/25) of the herds were seropositive. The HEV prevalence in the liver was 17.2% (43/250). Each positive liver sample originated from seropositive herds respectively from HEV seropositive pigs. This study demonstrates for the first time the significant correlation between a positive HEV serology and the occurrence of HEV RNA in the liver of slaughter pigs (χ2 = 31.83; p < 0.001), highlighting the significant predictive power of positive serological results on the occurrence of HEV RNA in the liver.