Filip Dámek , Bastien Fremaux , Dominique Aubert , Sandra Thoumire , Maxime Delsart , Jean-Luc Martin , Sandra Vuillermet , Marieke Opsteegh , Pikka Jokelainen , Delphine Le Roux , Pascal Boireau , Isabelle Villena , Radu Blaga
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引用次数: 1
Abstract
Toxoplasma gondii is an important zoonotic foodborne parasite. Meat of infected animals appears to be a major source of infection in Europe. Pork is the most consumed meat in France, with dry sausages well represented. The risk of transmission via consumption of processed pork products is largely unknown, mainly since processing will affect viability but may not entirely inactivate all T. gondii parasites.
We investigated the presence and concentration of T. gondii DNA in the shoulder, breast, ham, and heart of pigs orally inoculated with 1000 oocysts (n = 3) or tissue cysts (n = 3) and naturally infected pigs (n = 2), by means of magnetic capture qPCR (MC-qPCR). Muscle tissues of experimentally infected pigs were further used to evaluate the impact of manufacturing processes of dry sausages, including different concentrations of nitrates (0, 60, 120, 200 ppm), nitrites (0, 60, 120 ppm), and NaCl (0, 20, 26 g/kg), ripening (2 days at 16–24 °C) and drying (up to 30 days at 13 °C), by a combination of mouse bioassay, qPCR and MC-qPCR.
DNA of T. gondii was detected in all eight pigs, including in 41.7% (10/24) of muscle samples (shoulder, breast and ham) and 87.5% (7/8) of hearts by MC-qPCR. The number of parasites per gram of tissue was estimated to be the lowest in the hams (arithmetic mean (M) = 1, standard deviation (SD) = 2) and the highest in the hearts (M = 147, SD = 233). However, the T. gondii burden estimates varied on the individual animal level, the tissue tested and the parasitic stage used for the experimental infection (oocysts or tissue cysts). Of dry sausages and processed pork, 94.4% (51/54) were positive for T. gondii by MC-qPCR or qPCR, with the mean T. gondii burden estimate equivalent to 31 parasites per gram (SD = 93). Only the untreated processed pork sample collected on the day of production was positive by mouse bioassay.
The results suggest an uneven distribution of T. gondii in the tissues examined, and possibly an absence or a concentration below the detection limit in some of them. Moreover, the processing of dry sausages and processed pork with NaCl, nitrates, and nitrites has an impact on the viability of T. gondii from the first day of production. Results are valuable input for future risk assessments aiming to estimate the relative contribution of different sources of T. gondii human infections.
期刊介绍：
Food and Waterborne Parasitology publishes high quality papers containing original research findings, investigative reports, and scientific proceedings on parasites which are transmitted to humans via the consumption of food or water. The relevant parasites include protozoa, nematodes, cestodes and trematodes which are transmitted by food or water and capable of infecting humans. Pertinent food includes products of animal or plant origin which are domestic or wild, and consumed by humans. Animals and plants from both terrestrial and aquatic sources are included, as well as studies related to potable and other types of water which serve to harbor, perpetuate or disseminate food and waterborne parasites. Studies dealing with prevalence, transmission, epidemiology, risk assessment and mitigation, including control measures and test methodologies for parasites in food and water are of particular interest. Evidence of the emergence of such parasites and interactions among domestic animals, wildlife and humans are of interest. The impact of parasites on the health and welfare of humans is viewed as very important and within scope of the journal. Manuscripts with scientifically generated information on associations between food and waterborne parasitic diseases and lifestyle, culture and economies are also welcome. Studies involving animal experiments must meet the International Guiding Principles for Biomedical Research Involving Animals as issued by the Council for International Organizations of Medical Sciences.
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