Reductionin Listeria monocytogenes,Salmonella enterica and Escherichia coli O157:H7 in vitro and on tomato by sophorolipid and sanitiser as affected by temperature and storage time

Increased consumption of produce by consumers has been attributed to perceived health benefits of postharvest produce. Pathogen control is crucial because periodic occurrences and contamination of tomato and leafy greens have exacerbated food safety risks for consumers. We investigated the effects of temperatures (5 and 25 °C), storage time (30 min and 24 h) for inactivation of Listeria monocytogenes, Salmonella enterica and Escherichia coli O157:H7 by sophorolipid (SL‐p) produced fermentatively using palmitic acid as a co‐substrate at different concentrations in vitro. Reduction in pathogenic bacteria on grape tomato by SL‐p, sanitiser (Lovit) and combinations of SL‐p and sanitiser was determined. Temperature and storage time significantly (P < 0.05) affected pathogen inactivations by SL‐p as pathogen reductions were greater at 25 °C and 24 h than at 5 °C and 30 min of storage. L. monocytogenes was the most sensitive to SL‐p treatment as reductions of 5 log relative to untreated controls were attained at 0.12% of SL‐p. Significant reductions in S. enterica (1.91–3.85 logs) and E. coli O157:H7 (0.87–4.09 logs) were recorded at 2–5% of SL‐p. Lower populations of Salmonella and E. coli O157:H7 were inactivated than L. monocytogenes. On grape tomato, pathogen populations inactivated increased at higher SL‐p levels at 25 °C. Sanitiser and sanitiser + SL‐p reduced bacterial populations on tomato by 5.29–5.76 logs and 0.71–3.3.66 logs, respectively. These results imply the interactions of temperature, storage time and SL‐p significantly (P < 0.05) affected pathogen strain reductions. The combination of SL‐p with sanitiser led to synergistic effect on E. coli O157:H7, but not L. monocytogenes and S. enterica.     

旱地西红柿种植技术

随着人民生活水平的提高,旱地西红柿种植面积逐年增大,但由于种植技术的缺乏,产量和质量均得不到提高。文章通过多年的研究,对西红柿从育苗、施肥、覆膜种植到管理进行了系统的阐述,有效提高山区人民旱地西红柿的种植水平,增加农民收入。     

番茄安全高效设施栽培技术

番茄是人们喜爱的一种蔬菜,品质的优劣决定于安全高效的栽培技术,文章从番茄对环境条件的要求、栽培类型、栽培季节、栽培技术的要求阐述番茄安全高效设施栽培技术。     

液相色谱—串联质谱法测定番茄和黄瓜中敌菌灵残留量

样品采用固相萃取小柱净化,以C18色谱柱为分离柱,以甲酸水—乙腈为流动相进行梯度洗脱,经LC-MS/MS检测,以多反应监测模式检测目标化合物的特征离子进行定性定量分析。结果表明:该方法线性范围为0.1～10.0μg/mL,线性相关系数0.999 0,方法的检出限为0.01mg/kg,定量限为0.03mg/kg。在加标水平为0.03,0.10,0.50 mg/kg时,方法的回收率为88.3%～95.2%,RSD在4.5%～8.8%。该方法前处理方式简便、有机溶剂用量少、分析时间短、选择性好且灵敏度高,适用于番茄和黄瓜中敌菌灵的检测。     

Development of non-enzymatic ZnO nanocomposite-based optical sensor for l-lactate detection in tomato samples

l -lactate is a conjugate base of α-hydroxy acid, a key organic chemical in food processing, fermentation, biology and chemical industries. We are reporting for the first time a facile and rapid non-enzymatic nanosensor for l -lactate detection in tomato-based products using 3-aminophenylboronic acid (3-APBA)-added zinc oxide nanoparticles (ZnO NPs). 3-APBA-functionalised ZnO NPs have a selective and stable SPR intensity change at pH 5.5 to 7.5 and forms a reversible ester with bound l -lactate revealing the wavelength shift from λ = 300 nm to 288 nm in UV-VIS absorption spectrometry. In the spiked (2.5–20 mm ) samples of tomato puree, absorption peak increased as per l -lactate addition with the lower detection limit of 3.98 mm . l -lactate binds with a trigonal form of 3-boronate, thereby generating the tetrahedral complex. ZnO NPs stabilise the tetragonal complex. Nanosensor validated with standard HPLC. This method is useful for l -lactate detection and alternates to conventional techniques.     

水溶性番茄浓缩物抗氧化和辅助降血脂功效研究

目的：研究水溶性番茄浓缩物抗氧化和辅助降血脂功效。方法：通过检测老龄小鼠的脂质氧化产物含量、蛋白质羰基含量、还原性谷胱甘肽含量、抗氧化酶活力观察水溶性番茄浓缩物抗氧化作用,通过建立大鼠高脂血症模型,研究水溶性番茄浓缩物对高脂血症模型动物的降血脂作用。结果：水溶性番茄浓缩物对老龄小鼠血清脂质氧化产物含量、蛋白质羰基含量有一定的降低作用,能降低高脂血症模型动物血清胆固醇含量。结论：水溶性番茄浓缩物具有抑制体外脂质过氧化的作用, 能调节高脂模型动物胆固醇水平。     

Lycopene-rich cream obtained via high-pressure homogenisation of tomato processing residues in a water–oil mixture

Tomato processing residues are still rich in bioactive compounds that may be recovered and reused, with environmental and economic benefits. This short communication discloses for the first time that the high-pressure homogenisation (HPH) treatment of tomato residues in the presence of water and sunflower oil is able to promote the extraction of bioactive compounds concurrently to the formation of an oil-in-water emulsion stabilised by the micronized residues. The mechanical disruption effect of HPH improved the mass transfer of lycopene into the oil phase, and formed fine fibrous debris, improving stabilisation and visual appearance of the emulsion. Results showed a progressive increase of lycopene concentration in the cream phase up to 5 HPH passes and a concurrent reduction of its content in the pellet. Total polyphenols content and antioxidant activity in the aqueous phase gradually decreased when increasing the number of passes, suggesting their progressive transfer in the cream phase. The proposed process that relies on a purely physical treatment and uses only water/sunflower oil as extraction media resulted in the production of a lycopene-rich cream of potential use as a functional food ingredient.