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Toxoplasma gondii is a widely spread protozoon in humans, mammals and poultry. Regarding the latter, nothing is known yet about the duration of T. gondii persistence and distribution over a conventional fattening cycle of turkeys and chickens. Twenty-four turkeys and 12 broiler chickens were infected intravenously with 1×10(6) T. gondii tachyzoites (strain NED). Serum antibody levels were determined weekly by ELISA (turkeys) or immunofluorescent antibody test (chickens). Turkeys were slaughtered at 4, 8, 12 and 16 weeks post-infection (p.i.), and chickens 5 or 10 weeks p.i. (n = 6 per group). Sixteen different tissue samples per bird were analysed for T. gondii by PCR. All infected animals showed seroconversion. In turkeys, 15.9% of all samples were tested positive for T.-gondii-DNA. Among the edible tissues (drumstick, thigh, breast muscle, heart, liver and gizzard) 7.8% tested positive. Among poultry slaughtered after different periods of time after infection no significant differences (P>0.05) regarding the number of positive samples were observed. Only 4 out of 192 samples (2.1%) from infected chickens contained detectable T. gondii DNA.The PCR findings suggested that T. gondii may persist in poultry. Particularly in turkey it was shown that edible tissues stay infected for at least 16 weeks p.i. which indicates a potential risk for consumers of undercooked turkey meat whereas chickens appear less susceptible to T. gondii infection.

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Food fraud is becoming a prominent topic in the food industry. Thus, valid methods for detecting potential adulterations are necessary to identify instances of food fraud in cereal products, a significant component of human diet. In this work, primer–probe systems for real-time PCR and droplet digital PCR (ddPCR) for the detection of these cereal species: bread wheat (together with spelt), durum wheat, rye and barley for real-time PCR and ddPCR were established, optimized and validated. In addition, it was projected to validate a molecular system for differentiation of bread wheat and spelt; however, attempts for molecular differentiation between common wheat and spelt based on the gene GAG56D failed because of the genetic variability of the molecular target. Primer–probe systems were further developed and optimized on the basis of alignments of DNA sequences, as well as already developed PCR systems. The specificity of each system was demonstrated on 10 (spelt), 11 (durum wheat and rye) and 12 (bread wheat) reference samples. Specificity of the barley system was already proved in previous work. The calculated limits of detection (LOD95%) were between 2.43 and 4.07 single genome copies in real-time PCR. Based on the “three droplet rule”, the LOD95% in ddPCR was calculated to be 9.07–13.26 single genome copies. The systems were tested in mixtures of flours (rye and common wheat) and of semolina (durum and common wheat). The methods proved to be robust with regard to the tested conditions in the ddPCR. The developed primer–probe systems for ddPCR proved to be effective in quantitatively detecting the investigated cereal species rye and common wheat in mixtures by taking into account the haploid genome weight and the degree of milling of a flour. This method can correctly detect proportions of 50%, 60% and 90% wholemeal rye flour in a mixture of wholemeal common wheat flour. Quantitative results depend on the DNA content, on ploidy of cereal species and are also influenced by comminution. Hence, the proportion of less processed rye is overestimated in higher processed bread wheat and adulteration of durum wheat by common wheat by 1–5% resulted in underestimation of common wheat.