Preparing of calibration curves are critical steps for accurate quantitative LC-MS bioanalysis. Traditional multi-sample external calibration curve (MSCC) is labor-intensive and prone to error. In this study, a novel strategy of one sample multi-point calibration curve (OSCC) using multiple isotopologue reaction monitoring (MIRM) was proposed and validated using LC-MS for the quantitation of six aflatoxins in milk and oat-based milk samples. The developed MIRM-OSCC methodology is comprehensively validated and the results indicated that the established method exhibits good performance in selectivity, sensitivity, accuracy and precision. Furthermore, the OSCC could realize sample dilution by monitoring the MIRM channel with less intensity for samples beyond the upper limit of quantification, without the need of sample dilution, which improves the assay throughput. Considering the advantages of excluding the MSCC preparation and sample dilution in OSCC, this strategy can be widely applied in various fields such as drugs, food safety and environmental analysis.

Bovine (buffalo and cattle) meat and edible offal are considered as essential sources of the red meat worldwide. This study aimed at investigation of the mold contamination of the buffalo and cattle meat (round), and their edible offal including neck muscles, masseter muscles, liver, and kidney in a comparative way. Identification of the prevalent mold genera was followed. Besides, identification of the Aspergillus spp. to the species level was also conducted. The obtained results revealed higher mold contamination of the cattle samples compared with the buffaloes. In both species, neck muscles had the highest contamination rates, followed by kidney, liver, masseter muscles, and round, respectively. Aspergillus spp. was the most prevalent mold genera in all examined samples. Aspergillus niger (A. niger), A. flavus, A. fumigatus. A. ochraceous, A. parasiticus, and A. terreus were the identified Aspergilli. In conclusion, this study demonstrates isolation and identification of different molds from the retailed buffalo and cattle meat and edible offal. Therefore, strict hygienic measures should be adopted during all steps of preparation of such valuable protein sources.

The objectives of the present study were first to determine the residual contents of total aflatoxins (AFTs), lead (Pb), and cadmium (Cd) in the edible tissues of the cattle reared in Al-Ahsa, Saudi Arabia. Al-Ahsa is the largest governorate in the Eastern Province of Saudi Arabia. The two main economic activities of Al-Ahsa are oil production (industrial) and agriculture. Besides, dietary intake and possible health risks for Saudi population were further calculated. In order to establish potential molecular biomarkers for xenobiotic exposure in cattle, the mRNA expression of xenobiotic-metabolizing enzymes (XMEs) including cytochrome P450 (CYP) 1A1, NAD(P)H dehydrogenase [quinone] 1 (NQO1), metallothionein (MT) 1A, and heat shock protein (HSP) 70 was investigated in the different tissues of the cattle. The tested XMEs were selected because of their specific roles in the metabolism and detoxification of AFTs, Pb, and Cd. The obtained results revealed that the liver had significantly the highest AFT content, while all examined muscle samples had no AFT residues. Consumption of the bovine liver and kidneys represents the highest source for the dietary exposure to total AFTs (0.05-0.98 μg/kg/day), Pb (0.06-0.19 mg/kg/day), and Cd (0.08-0.19 mg/kg/day) among the examined tissues. Therefore, excessive intake of such organs might pose a public health concern, particularly among children. Significant upregulation of mRNA expressions of CYP1A1, NQO1, MT1A, and HSP70 was observed in the different tissues of the cattle in comparison with the muscle. This upregulation had significant positive correlation with the accumulated AFTs, Pb, and Cd. This indicates the possible use of CYP1A1, NQO1, MT1A, and HSP70 as potential biomarkers for the exposure of the cattle to AFTs, Pb, and Cd.

Antimicrobial resistance is an increasingly serious threat to global public health that requires action across all government sectors and society. The aim of this study was to determine the rate of extended-spectrum β-lactamases (ESBL)-producing E. coliisolation from minced camel meat and identify the phenotype and genotype of the ESBL. A total of 150 samples were collected randomly from butchers’ shops in Al-Ahsa, Saudi Arabia. The results indicated that, overall, 17 (11.3 %) E. coliisolates were recovered from the minced meat samples. The isolates were classified biochemically at the species level using the VITEK 2 system. The antibiotic susceptibility of E. coliisolates was determined based on their MIC profile. The highest resistance was determined to be ampicillin (64.7%), doxycycline (23.5%), cefotaxime (23.5%) and ciprofloxacin (17.6%).Multidrug resistance (MDR) was determined in four isolates. Screening of the 17 isolates for ESBLs revealed that, four strains were resistant to cefotaxime and ceftazidime.A combination disk test (CDT) was used for ESBL phenotype conformation. The ESBL-encoding genes were characterized by PCR. The four isolates produced CTX-M group-1 ESBLs. The blaSHV gene was detected in one isolate and blaTEMin two isolates. The eaeAgene was detected in 3 isolates, stx2gene in two isolates with the hlyAgene in one isolate. It can be concluded that there is clear evidence of the circulation of ESBLs producing E. coliin the minced camel meat. A high resistance was determined to ampicillin and doxycycline. The molecular detection of virulence genes may suggest the transmission of foodborne illness to consumers