Current major degradation methods for aflatoxins: A review

BackgroundAflatoxins are strong cancerogenic compounds predominantly produced by certain strains of the Aspergillus genus. Due to their extreme stability in different conditions, it is very difficult to remove them completely in human diet and animal feeds. In this way aflatoxins are triggering numerous healthy problems (such as liver cancer) and thus becoming a huge burden to the hygiene system and food industry worldwide.Scope and approachTherefore, seeking for an effective technique to degrade aflatoxins to a threshold level has been a “hot-topic” among researchers. Traditional methods to detoxify aflatoxins include physical and chemical treatments, such as an extrusion cooking process and ammoniation, respectively. Meanwhile a bio-degradation by microorganisms gains its popularity due to its friendliness to both environment and body health. Natural phytochemicals (plant extracts) which have great capability to remove aflatoxins without causing any damage on human and animals come out as an improvement.Key findings and conclusionHowever, a fully and systematically discussion of the methods of detoxification for aflatoxins is still not available. Therefore, in the present review we briefly enumerate several traditional strategies, update newly methods, particularly the potential use of natural phytochemicals, and discuss some mechanisms during the detoxification period, summarizing merits and demerits of these methods. We suggest that this important information and our humble opinions could help researchers to understand the degradation of methods for aflatoxins.     

Detection of viable but non-culturable Escherichia coli O157:H7 from vegetable samples using quantitative PCR with propidium monoazide and immunological assays

Quantitative differentiation of the live fraction of pathogens in raw food samples is highly critical from a public health risk perspective, as many studies have shown that under stress conditions major foodborne pathogens enter a viable but non-culturable (VBNC) state in which bacteria can remain for long periods of time and maintain the potential for virulence. The objective of this study was to evaluate the applicability of propidium monoazide (PMA) quantitative PCR (qPCR) and immunological methods for detection of Escherichia coli O157:H7 VBNC populations induced by low temperature on the surface of lettuce and spinach plants. The primer/probe set selected influenced the qPCR signal in mixtures with a defined ratio of viable and non-viable cells. The PMA qPCR used in a background of added dead pathogens and epiphytic bacteria gave a detection limit of 10³ CFU/g leaf and a linear quantitative detection range of 5 log. During quantification of VBNC cells from lettuce and spinach samples there was a good correlation between the PMA qPCR results and viable counts detected by microscopy, showing that PMA qPCR gives an accurate indication of the VBNC population. However, the commercially available immunoassay methods used to detect Shiga-like toxin production and the O157 antibody in vegetable samples with no detectable culturable pathogen underestimated the number of samples contaminated with E. coli O157:H7 VBNC cells. Results indicate that PMA qPCR is a suitable technique for the detection and quantification of VBNC cells of foodborne pathogens in contaminated raw lettuce and spinach.     

Rapid detection of adulteration of cold pressed sesame oil adultered with hazelnut,canola, and sunflower oils using ATR-FTIR spectroscopy combined with chemometric

Sesame oil is one of the most valuable oil due to its bioactive properties, unique taste, odor, and flavor. Therefore, consumers tend to consume and willing to pay a higher price for sesame oil due to increasing awareness of consuming healthier and better food. However, sesame oil is subjected to adulteration risks with lower price vegetable oils which impairs consumer rights and human health. In this study, we purposed an ATR-FTIR based method for the rapid detection of food adulteration in sesame oil. For this purpose, sesame oil was adulterated with hazelnut, canola, and sun flower oils in different concentrations ranged from 1 to 50%. Cluster analysis of FTIR spectra was performed for differentiation and classification of pure sesame oil from adultured vegetable oil samples. In addition, a calibration curve was obtained to determine relationship between actual adulterant concentration and FTIR predicted concentrations using partial least square (PLS) method for each oil samples. According to these results, it could be concluded that ATR-FTIR technique has a potential for adulteration of sesame oil as a non-destructive, rapid, and effective alternative method.     

高效液相色谱-高分辨质谱-同位素内标法测定乳粉中的胆碱

目的 建立高效液相色谱－高分辨质谱-同位素内标法测定乳粉中胆碱的含量。方法 奶粉样品用水溶解, 加入硫酸铜溶液(70 g/L)和氢氧化钠溶液(40 g/L)沉淀蛋白, 离心后过0.45 μm粒径的微孔膜, 经ZORBAX SB-Aq C18色谱柱, 以0.1%甲酸水和乙腈为流动相进行梯度洗脱, 流速0.60 mL/min; 柱温箱温度30 ℃。质谱采用正离子模式分析, 同位素内标法定量。结果 该方法在0.5~10 μg/mL范围内线性关系良好, 相关系数为0.9998。平均加标回收率为91.4%~99.7%, 相对标准偏差为1.0%~3.2%(n=5), 检出限为0.2 mg/100 g, 定量限为0.5 mg/100 g。结论 该方法预处理简单, 分析速度快, 检测成本低, 能满足奶粉中胆碱的检测要求。     

Antimicrobial activity in cheese whey as an indicator of antibiotic drug transfer from goat milk

Raw goat milk spiked with antibiotics was coagulated with rennet, the whey separated and the transfer of 18 antibiotics from the milk to the whey was evaluated by estimating antimicrobial activity of the whey using microbial inhibitor tests. Antibiotic-free whey (negative whey) spiked with different antibiotics was used as a reference. The antimicrobial activity in whey from milk spiked with most β-lactam drugs was lower (0–40%) than that of the reference whey, suggesting that these antibiotics are mostly released from curd and transferred to the whey. However, for most non-β-lactam drugs, an 84–100% reduction in the relative antimicrobial activity in whey was obtained, indicating the higher susceptibility for retention in curd. The traceability of antibiotics through the cheese-making process will make it possible to determine whether control systems are required to prevent the negative implications of the presence of antibiotic drug residues in cheese and whey products.     

Comparison of the effects of novel processing technologies and conventional thermal pasteurisation on the nutritional quality and aroma of Mandarin (Citrus unshiu) juice

Conventional thermal pasteurisation (90 °C and 30 s), high pressure processing (HPP: 600 MPa, 4 °C and 300 s), ultrasound processing (US: 50 °C, 750 W and 36 min) and microwave processing (MW: 800 W, 80 °C and 70 s) were evaluated by examining their effects on the sensory and nutritional qualities of mandarin juice. The treated samples had <2 log CFU/mL total aerobic bacteria, which is equivalent to microorganism inactivation. Sugar and acid components were almost constant for all the treated mandarin juices, and no differences between treatments were perceptible. However, the mandarin juice treated with novel technologies maintained better colour (L*, a* and b*), nutritional value (ascorbic acid, total phenolic, total carotenoid content and phenolic components) and aroma than the thermally pasteurised one. This study showed that US, MW and HPP are good novel processing techniques to inactivate microorganisms and maintain the sensory and nutritional quality of mandarin juice.