The subject of this study is the validation of a high-performance liquid chromatography method for the analysis of amino acids in feed. The contents of amino acids were determined in maize, soybean, soybean meal, as well as in their mixtures enriched with different amounts of methionine, threonine and lysine. The method involves the acid hydrolysis of the sample (6 h at 150?C), automated derivatisation of amino acids with the aid of o-phthaldialdehyde and 9-fluorenylmethyl chloroformate reagents, separation on the ZORBAX Eclipse-AAA column, and detection using a diode-array detector. The method is characterized by high specificity (the difference between the retention times of the feed samples and standard mixtures are below 1.7 %), wide linear range (from 10 to 1000 nmol cm-3, r2 = 0.9999), high accuracy (recovery 93.3-109.4 %), and the precision of the results (RSD below 4.14 % in case of repeatability and below 4.57 % in the case of intermediate precision). The limit of detection and the limit of quantification are in the range 0.004-1.258 ?g cm-3 and 0.011-5.272 ?g cm-3, respectively. The results demonstrate that the procedure can be used as a method for the determination of the composition of primary amino acids of feed proteins.

Honey’s unique qualities should last for several years when properly stored. Therefore, it is up to manufacturers to choose the right shelf life for their product while also considering the product’s nature. Physicochemical parameters (water content, electrical conductivity, free acidity, pH, ash, water-insoluble matter, hydroxymethylfurfural (HMF), sugar content and composition, and diastase activity) were analyzed in 24 samples of sunflower honey collected from several localities in Vojvodina, Serbia. Crystallization indices were also calculated. Furthermore, the impact of eighteen months of room temperature storage (22 ± 2 °C) in a dark place on selected physicochemical parameters (water, HMF, diastase activity, pH value, and free acidity) was investigated. The results of the initial test indicated that the tested samples of sunflower honey from Vojvodina is of good quality because the parameters under examination revealed results that were within the legal bounds of both national and European legislations. Eighteen months of storage at room temperature reduced diastase activity by 2 times, increased HMF content by about 17 times, and decreased the pH value of honey from a mean value of 3.66 to 3.56. The water content was relatively stable at 17.01% before storage and 16.29% after storage. The storage of sunflower honey did not have an impact on the free acidity.

Fifty two honey samples of different floral origin from Serbia were examined in order to define their sugar composition. Our study confirmed that in the examined honey types the average percentage of fructose and glucose ranged from 36.57 to 41.64, and from 30.00 to 34.53%, respectively. The sum value of glucose and fructose, as well as sucrose content in all investigated honey samples, was found to meet European Legislation and local regulations. Besides, fructose/glucose ratio (F/G) and glucose/water ratio (G/W) were calculated for all types of honey. According to our results, acacia honey had the lowest G/W ratio and greatest F/G ratio, hence indicating scarce tendency to crystallize. Univariate data analysis and multivariate chemometric techniques were applied to determine the relationship between the values of relevant chemical parameters and the botanical origin of honey.

Histamine levels in fish and fish products are regarded as a primary criterion for food safety, considering the effects of histamine on human health. The aim of this research was to describe a case of massive histamine intoxication in Serbian children and to provide relevant information regarding the presence of histamine in imported marine fish and fish products available in the Serbian market. In January 2014, an incident of foodborne illness occurred in 28 children (aged 2 to 5 years) who consumed canned sardines in a kindergarten in Vojvodina province, northern Serbia. The diagnosis was established based on anamnestic data, epidemiological data, and clinical symptoms and confirmed by positive histamine finding in the incriminated sardines. Substantially high histamine levels (>300 mg/kg) were detected in seven of the nine examined units of these canned sardines. In addition, during an official veterinary border control from January 2013 to January 2015, 273 lots in total, including 2,457 fish and fishery product units, were analyzed using enzyme-linked immunosorbent assay. Even though only nine (3.29%) of all examined lots were declared as unsafe for human consumption, the presented case of histamine intoxication strongly suggests the importance of border inspection and comprehensive control of each imported lot.