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A purpose of this study was to demonstrate the feasibility of using near infrared refl ectance spectroscopy (NIRS) to identify MBM (meat-and-bone meal) in the ruminant concentrates. A partial least squares discriminant analysis equation was developed with 235 samples and validated with 59 samples. A calibration model was developed based on spectra region from 1100 to 2498 nm with mathematic pretreatment 2,4,4,1 and with scatter correction SNVDT (the standard normal variate-detrending). For external validation, there was the accurately discriminant rate of 100%. The results indicated that NIRS could provide a rapidly method for detecting the adulteration of ruminant concentrates with MBM.

Environment, layer farm, PCR, Salmonella Enteritidis.Submitted: 17/October/2016 Approved: 16/February/2017 ABStRACt Salmonella enterica subspecies enterica serotype Enteritidis (SE) has caused foodborne infections over decades. It is transmitted mainly from contaminated eggs to humans. SE is commonly present in layer houses, and closely interacts with environmental factors. The objective of the present study was to develop a viable PCR method to identify SE in environmental samples collected in layer farms of different sizes, and to evaluate SE contamination status in four main egg-production provinces of northern China. After specificity retrieval using Primer-BLAST against the NCBI database, three SE specific oligonucleotide primers were selected as candidate primers. The primers targeting Prot6e gene were adopted and primers targeting Sdf I were also selected to validate the results, after testing eight different types of pooled poultry environmental samples (overshoe, air, drinking nipple, feed, egg collection belt, eggshell, air inlet, and air outlet) by PCR. A PCR detection limit of 1 CFU/mL was determined using cell lysates from pure cultures. Testing time was less than 48 h. On-farm samples were collected from two layer farm sizes (one housing more than 50,000 layers, and the other, less than 50,000 layers) in each province. The applied PCR method was shown to be simple, inexpensive and effective for screening SE in a large amount of farm samples. The study identified only one SE-positive farm, which a large farm and where nine samples were found to be contaminated with SE: drinking nipples (3), egg collection belt (1), air inlet (1), air (1), overshoe (1) and eggshell (2).

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