Arsenic (As) is one of the toxic, persistent, and lethal heavy metalloids and requires rapid, less costly, and sensitive detection methods. This study proposed a label-free cuprous oxide/silver (Cu2O/Ag) surface-enhanced Raman scattering (SERS) nanoprobe to detect total As in tea. Different total As spiked tea concentrations were mixed with the Cu2O/Ag SERS nanoprobe for the SERS detection. Quantitative models were established for predicting the total As in tea by comparatively applying chemometric algorithms. Amongst the algorithms, competitive adaptive reweighted sampling partial least squares (CARS-PLS) optimized the most effective spectral variables to predict the total As in tea efficiently. The CARS-PLS gave the highest correlation coefficient value (R-p = 0.9935), very low root means square error (RMSEP = 0.0496 mu g g(-1)) in the prediction set and recorded the highest RPD value of 8.819. The proposed nanoprobe achieved a lower detection limit (0.00561 mu g g(-1)), excellent selectivity, satisfactory reproducibility, and stability. No significant difference was recorded when the performance of the Cu2O/Ag total As SERS sensor was compared with the inductively coupled plasma mass spectrometry (ICP-MS) method. Therefore, this developed Cu2O/Ag coupled chemometrics SERS sensing method could be used to efficiently determine, quantify, and predict total As in tea to promote monitoring of heavy metal contaminants.
Lead ion (Pb2+) is a main heavy metal in food that causes heavy teratogenicity and carcinogenicity. In this study, a rapid and sensitive SERS method for detecting Pb2+ in food was established by aptamer regulating gold nanoparticles reduction. The reduction of HAuCl4 catalyzed by H2O2 is a slow process, and graphene oxide (GO) has excellent catalytic performance for the reaction, which enabled the system to generate gold nanoparticles (AuNPs) with high Raman activity. When the aptamer was introduced into the system, its binding with GO reduced the reaction speed. Upon adding Pb2+ to the system, the aptamer preferentially combined with Pb2+ and GO was released to accelerate the AuNPs production. The concentration of the AuNPs was proportional to the intensity of the added Raman signal molecule 4-MBA and the main Raman peak of Pb2+ appeared at 1595.80 cm(-1). The ability of a novel aptamer (M4-16) and traditional aptamers (T30695, TBA) for Pb2+ determination was compared, and the concentration of the aptamer, HAuCl4 and heating time were optimized to build optimal detection system. After several pretreatment of the original SERS spectroscopy, combined with the comparison of various models, the first-order derivative preprocessing combined with competitive adaptive reweighted sampling model achieved the best performance (R-c = 0.9966, R-p = 0.9972), the detection limit for Pb2+ was 0.1 mu g L-1. The combination of SERS technology and chemometrics is a promising method that could be used to achieve rapid and highly sensitive detection of Pb2+ in food.
Targeted nuclease based genome editing technology particularly clustered regularly interspaced short palindromic repeats (CRISPR) that allows to manipulate virtually almost any genomic sequences has greatly facilitated both basic and applied researches in plants. However, so far, very few of them has entered to the field and much less to the kitchen table. This review starts with a brief summary of current status of the application of genome editing in crop science and crop breeding and, then identifies technical, ethical, intellectual and other challenges for the commercialization of genome edited crops. This review explores further advances in the specificity and the prediction and detection of off-targets of CRISPR system, and highlights the importance of molecular characterization and the introduction of novel techniques such as nanotechnology to CRISPR system. Finally, this review calls for collaborative efforts in proposing principles and guidelines for moving genome edited crops forward from the laboratory bench to the kitchen table, and emphasizes the equal importance of public outreach.
Home and Consumer Studies (HCS) should be a suitable place for food safety education as it includes plenty of practical cooking and is compulsory for all students in the Swedish school system. A study among HCS teachers however reveals shortcomings in food safety teaching. A survey regarding food safety knowledge and behaviour among HCS students in school Year 9 was performed at different schools with a new system to collect questionnaire data. A Student Response System was used at the participating schools. The students were to answer the questions by using a small handheld wireless control, a clicker, in the response program Turning Point 2008. The questionnaire included a total of 26 questions and all questions were shown at PowerPoint slides and read out loud to the students. Some trivial questions were asked at the beginning to ensure the method. A total of 529 students from 18 different schools in different parts of Sweden participated in the survey conducted between September 2013 and January 2014. The survey results were evaluated and analysed using SPSS by performing cross-tabulation and chi-square tests. This study reveals that the students' self-reported food safety knowledge and behaviour are inadequate. Important risk areas need to be highlighted in HCS teaching. Boys reported to be significantly more at risk in terms of food safety regarding the handling of risk foods, reheating and cleaning. Especially for boys who reported seldom cook at home HCS would be extra valuable. This study also indicates the importance of reflection in relation to the hygiene routines which are common in the HCS context. The outcome of this study is that students might leave school without even basic food safety knowledge.
International studies have noted shortcomings in food safety knowledge and behaviour among university students. In general students do not constitute a pronounced risk group but there are wider implications. In a foreseeable future some of them will become pregnant and a majority will be responsible for vulnerable groups in their near environment. A crucial question exists, therefore, about their food safety knowledge and safe food handling practices. The aim of this study is to investigate food safety knowledge, sources thereof and self-reported food safety behavior among university students in Sweden. A quantitative study design using a web-based questionnaire was chosen as the data collection method. The questionnaire was distributed through social media and e-mail. Among the 606 respondents from 24 Swedish universities 80% were 18-30 years and 78% were women. The average number of correct answers on the knowledge questions was 7.61 out of 12 (63.4%). The foremost source of food safety knowledge was "Family and friends" (45%). Just 21.1% reported Food safety education as a source, although 35.6% had experience of a course in food hygiene/safety and/or microbiology. Respondents who reported "Family and friends" to be the foremost food safety source of knowledge also got a significantly lower rate of correct answers. Students who estimated their food safety knowledge to be good also had more correct answers. Experience of food safety education at secondary school/university/working place/polytechnic school significantly correlated with more correct answers on the knowledge questions and indicated a safer self-reported behaviour. Those with fewer correct answers also reported more unfavourable behaviours. The present study indicates that education promotes more optimal behaviors. The authors would suggest a more systematic food safety education at younger ages.
Milk production is an important livelihood source for smallholder dairy farmers in low-to-middle-income countries (LMICs) such as Kenya. However, milk quality and safety are a challenge due to unhygienic handling and non-adherence to food safety standards. The objective of this study was to investigate the knowledge, attitudes and adoption of milk quality and food safety practices by smallholder farmers in Kenya. Ten Focus Group Discussions (FGDs), involving 71 smallholder farmers, were held to collect qualitative data on knowledge, attitudes and practices (KAPs) of smallholder dairy farmers in Laikipia, Nakuru, and Nyandarua counties. Additionally, data were collected through a cross-sectional administered to 652 smallholder farming households. The results of the study revealed low knowledge level and negative attitudes towards respecting antibiotics treatment withdrawal periods, milk quality standards and food safety regulations. Farmers stated they had received low levels of training on milk quality and safety standards. The majority of farmers adopted animal health measures and hygienic measures such as hand washing and udder cleaning. However, unhygienic milking environments, the use of plastic containers, the use of untreated water, and lack of teat dipping compromised milk quality and safety. Currently, milk production, handling and consumption could expose actors along the dairy value chain to health risks. The adoption of milk quality and food safety practices was influenced by farmers' knowledge, socioeconomic characteristics, and choice of marketing channel. There is a need to improve farmers' knowledge and attitudes and implement hygienic control, disease control and antibiotic residue control practices in the milk production process to meet required milk quality and food safety standards. Awareness campaigns and training programmes for smallholder dairy farmers could foster behavioural change and lead to an improvement in milk quality in Kenya.
Poor milk safety constitutes a persistent public health risk in Kenya. Poor milk composition, microbial contamination and adulteration is a constraint to dairy sector development. We hypothesise that variation in milk quality and safety depends on variation between farming systems. We argue that this variation between farming systems is associated with spatial location which affects the agro-ecological conditions and the avail-ability of labour and land. We used a spatial framework based on the distance to urban markets to distinguish the following farming systems: relatively intensive dairy systems in urban locations (UL), semi-intensive dairy systems in mid-rural locations (MRL) and extensive dairy systems in extreme rural locations (ERL). We aimed to investigate the variation in the quality of raw milk in these dairy farming systems and associated value chains in central Kenya. For this reason, we combined several methods such as participatory rural appraisal, participant observation, and milk physicochemical and microbiological analyses to collect data. Milk samples were collected at the informal and informal value chain nodes farms, informal collection centres, informal retailing centres including milk vending machines, and formal bulking centres where milk changes hands between value chain actors. Milk quality was compared to standards recommended by the Kenya Bureau of Standards (KeBS). There were no differences in the quality of raw milk between locations or between nodes. The overall milk physicochemical composition means (standard error) of the milk were within KeBS standards: fat 3.61 (0.05), protein 3.46 (0.06), solid-not fats 9.18 (0.04), density 1.031 (0.0002) and freezing point-0.597 (0.019). The protein percentage was below KeBS standards at all value chain nodes, except at the formal bulking node. There was significant contamination of milk samples: 16.7% of samples had added water, 8.8% had somatic cell count SCC above 300,000, 42.4% had E. coli, 47.9% had Pseudomonas spp., 3.3% had Staphylococcus spp. and 2.9% tested positive for brucellosis antibodies. Unsanitary milk handling practices were observed at farms and all value chains nodes. Milk physicochemical composition except for protein content meets the KeBS Standard. High levels of microbial contamination of milk pose a public health risk to consumers and show that urgent action is needed to improve milk quality.
Roselle (Hibiscus sabdariffa) quality is strongly influenced by several factors and the geographical origin is one of the key parameters. However, fraudulent practices including mislabeling of the geographical sources might occur. In the present experiment, the analyzed samples consisted of 64 authentic samples originating from the world's best roselle country (Sudan) and eight samples from the world's largest producer (China) were investigated. The study investigated whether near-infrared spectroscopy (NIR), low filed NMR (LF-NMR) spectroscopy and fluorescence spectroscopy can enable roselle geographical origin to be identified. Principal components analysis (PCA), hierarchical cluster analysis (HCA) and PCA combined with linear discriminant analysis (PCA-LDA) were performed on NIR data to assess a possible classification of samples based on origin. Roselle samples from the same geographical areas might group together in the PCA plot. Correct discrimination was achieved by HCA. The classification of the samples into calibration and prediction sets yielded 100% discrimination rates for both calibration and prediction sets. LF-NMR measurement, to detect differences in the relaxation times, indicated that these were affected by the variations in geographical origins. Additionally, the fluorescence spectroscopy spectra presented different shapes and intensity of fluorescence emissions, demonstrating the differences in the samples. This study proved that the three spectroscopies could be viable tools for utilization in classifying roselle samples by their geographical origins.