Despite high pressures for agricultural land conversion, increasing competition for water, and the low net benefits of rice production, rice is still by far the predominant farm occupation in the Vu Gia Thu Bon basin in Central Vietnam. This study examined the reasons for such persistence, by surveying and analyzing a comprehensive set of qualitative (planting and harvesting dates) and quantitative data (yields, labor and non-labor inputs, prices) for all the crops present in the cropping systems of 116 farms in the region. The net benefit derived from rice production was on average 23 M VND ha −1 , with a relatively low labor input of 144 man-day per ha −1 . The net benefits generated by vegetable production are more than 9 times higher (ca. 208 M VND ha −1 ) with a labor demand of ca. 928 man-day ha −1 . Despite the very high net benefits of vegetable production, in this region they do not translate into an equivalently high added value per man-day. These values are 'only' nearly double than those for rice, and not much higher than those for groundnut, chili, and watermelon. The results indicate that farmers' decisions for not rushing in diversifying production to vegetables are wise when looking at food security, the high risks of vegetable production, shortage of on-farm labor resources, and high opportunity costs of nonfarm income activities. Under current conditions, wage rate differentials between the agricultural and non-farm sector will most probably increase in favor of the latter. Thereby, policy measures towards promotion of the agricultural sector and diversification into larger production scales of high-value crops need to target improvements in effective marketing channels, capacity building in high-value crops specific technologies, as well as reduction of labor inefficiencies.

Reference materials are an important tool in ensuring the validity of the test results efficiently and economically. National Institute for Food Control has implemented several studies, characterization of microbiology chemistry for food and feeding stuffs certified reference materials (CRM) in order to support laboratories in control and maintaining test results quality. CRM for Escherichia coli (E. coli) in food is our study’s first interest, because E. coli indicates unfavorable hygienic conditions and fecal contamination in foods. Milk and dairy products are used for any stage of human life from infancy to elder. CRM for E. coli in milk-based products were characterized by using a network of competency laboratories leading to certified values in accordance with ISO 17034:2016 requirements. These certified reference materials produced are accredited conforming to ISO 17034:2016 by the America Association of Laboratories Association.

Isocyanate is a common name for chemical compounds containing one or more - NCO groups. There have been many studies showing that isocyanates pose a risk to human health when exposed and can cause occupational poisoning. When absorbed into the body, the isocyanates will be converted into the corresponding amines. Therefore, the determination of these diamines in urine will contribute to the assessment of exposure to isocyanates. This article presents a study on simultaneous determination of 4,4′-methylenedianiline (MDA), hexamethylene diamine (HDA), isophoron diamine (IPDA) in urine by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method detection limit (MDL) were 0.074, 0.059, and 0.053 ng/mL for HDA, MDA, IPDA, respectively. The method quantitation limit (MQL) were 0.243, 0.194 and 0.177 ng/mL for HDA, MDA, IPDA, respectively. The method's recovery ranged from 86.38 to 105.3% with the repeatability RSDr < 6%. The method was successfully applied to simultaneously determine the content of HDA, MDA and IPDA in 30 urine samples of workers at auto repair garages in Bac Ninh province. The results showed that HDA, MDA and IPDA were detected in these samples with different concentrations.

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Casein trong sữa và các sản phẩm từ sữa được xác định bằng phương pháp sắc ký lỏng hiệu năng cao (HPLC) với detector PDA tại bước sóng 280 nm và bằng phương pháp ELISA "kẹp" (sandwich). Phương pháp sắc ký lỏng cho phép định lượng được từng dạng casein (alpha, beta, kappa),xác định được tỷ lệ các dạng casein do đó cho phép đánh giá nguồn gốc sữa (sữa bò, sữa dê). Phương pháp ELISA cho phép xác định casein ở mức hàm lượng thấp, đáp ứng yêu cầu phân tích chất dị nguyên theo quy định hiện nay (10 mg/kg). Các kết quả thẩm định cho thấy phương pháp HPLC có giới hạn định lượng (LOQ) 0,8 g/100g, độ thu hồi đạt từ 78 – 98%, hệ số biến thiên tương đối trong khoảng 2,4 – 9,5%. Phương pháp ELISA có giới hạn phát hiện 3 mg/kg, độ thu hồi đạt từ 83 – 109%, hệ số biến thiên tương đối 11%. Các phương pháp đã được ứng dụng để xác định hàm lượng casein trong 20 mẫu sữa, cốm, bánh kẹo các loại được lấy trên thị trường Hà Nội.