Mitigation of Major Peanut Allergens by Pulsed Ultraviolet Light

Peanut allergy represents one of the most severe IgE-mediated reactions with food, but to date, the only effective way to prevent peanut allergy is total avoidance. If allergens could be mitigated during food processing before a product reaches the consumer, this would substantially lessen the food allergy problem. The efficacy of pulsed ultraviolet light (PUV), a novel food processing technology, on reducing peanut allergens, was examined. This study revealed for the first time that PUV was also capable of deactivating Ara h 2, the most potent allergenic protein of peanut. Protein extracts from raw and roasted peanuts were treated for 2, 4, and 6?min and peanut butter slurry was treated for 1, 2, and 3?min in a Xenon Steripulse XL 3000? PUV system. The distance from the central axis of the lamp was varied at 10.8, 14.6, and 18.2?cm. The SDS?CPAGE showed a reduction in the protein band intensity for Ara h 1, Ara h 2, and Ara h 3 at the energy levels ranging from 111.6 to 223.2?J/cm². Reduction of the protein band intensity for peanut allergens increased with treatment time but decreased with increased distance from the PUV lamp. The ELISA for peanut extracts and peanut butter slurry showed a reduction in IgE binding of up to 12.9- and 6.7-folds, respectively, compared to control.     

Surface Processing: Existing and Potential Applications of Ultraviolet Light

Solid foods represent optimal matrices for ultraviolet processing with effects well beyond nonthermal surface disinfection. UV radiation favors hormetic response in plant tissues and degradation of toxic compound on the product surface. Photoinduced reactions can also provide unexplored possibilities to steer structure and functionality of food biopolymers. The possibility to extensively exploit this technology will depend on availability of robust information about efficacious processing conditions and adequate strategies to completely and homogeneously process food surface.     

紫外线消毒对水处理系统的微生物的杀菌效果研究

紫外线消毒是一种有效经济的消毒方法,其能在几秒钟内杀灭病原微生物,并不残留有害物质和不影响水的风味或口感。生产用水中的微生物指标非常重要,本论文通过研究在紫外线杀菌前后,水处理系统中的水所含的大肠杆菌和菌落总数的变化情况。     

Biological Aspects in Food Preservation by Ultraviolet Light: a Review

The potential to commercialize nonthermal ultraviolet (UV) light technologies as new methods for preserving food products has caught the attention of a food industry that wishes to fulfill consumers' demands for fresh products. Numerous investigations have demonstrated UV light's ability to inactivate a wide range of microorganisms. However, the lack of UV sensitivity data from pathogenic and spoilage bacteria is evident. In addition, the main factors associated with UV light in terms of microbial lethality remain unclear. This review surveys critical factors (process, microbial, and environmental parameters) that determine UV microbial resistance and assess the effects of such factors on the inactivation mechanism and repair pathway efficiency. The effects of some of these factors, such as prior sublethal stresses and post-recovery conditions of UV treatments, may extensively improve the damage repair capacity and thus microbial survivability. Further research is needed to establish adequate control measures pre- and post-UV treatments. Furthermore, the possibility of combining UV light with conventional preservatives and other nonthermal technologies was assessed. The combination of UV light with mild heating or oxidant compounds could offer promising treatments to enhance the safety and stability of minimally processed foods.     

紫外吸收剂DF-1对真丝织物的防泛黄效果研究

介绍了真丝织物泛黄的机理及引起真丝织物泛黄的因素。对自制紫外吸收剂DF-1在真丝织物上的最佳整理工艺作了初步研究，结果表明DF-1有一定的防泛黄效果，且对真丝织物的强力、毛效影响不大。     

Advances in Ultraviolet Light Technology for Non-thermal Processing of Liquid Foods

A negative, public reaction is growing over the addition of chemical preservatives to liquid foods and beverages to extend their shelf life and to protect against foodborne pathogens. As a physical method, ultraviolet light (UV) irradiation has a positive consumer image and is of interest to the food industry as a low cost non-thermal method of preservation. Recent advances in the science and engineering of UV light irradiation have demonstrated that this technology holds considerable promise as an alternative to traditional thermal pasteurization for liquid foods and ingredients, fresh juices, soft drinks, and beverages. However, its use for treating foods is still limited due to low UV transmittance of liquid foods. The goal of this review is to provide a summary of the basic principles of UV light generation and propagation with emphasis on its applications for liquid food processing. The review includes information on critical product and process factors that affect UV light inactivation and consequently the delivery of a required scheduled process in liquids foods; measuring and modeling of UV inactivation, and the important effects of UV light on overall quality and nutritional value of liquid foods. The commercially available UV light sources and UV reactor designs that were used for liquid foods treatment are reviewed. The research priorities and challenges that need to be addressed for the successful development of UV technology for liquid foods treatment are discussed.     

紫外光对米酵菌酸的降解效果及动力学分析

米酵菌酸(BA)具有剧烈毒性,为了研究BA经紫外照射后的降解效果,以BA-甲醇水为研究模型,考察紫外照射强度、BA初始浓度、液层厚度对BA的降解效果,并对其降解曲线和降解方程进行拟合.结果表明,紫外光照射能有效降解BA,且降解过程符合一级动力学方程;紫外强度越强、BA初始越低、液层厚度越薄,BA的降解速率越快.在紫外强...     

纳米陶瓷粒子遮蔽紫外线织物的工艺分析

用纳米陶瓷粉体粒子作为紫外线遮蔽材料添加到涤纶材料中制成纤维 ,再用多相纤维进行混合纺纱 ,织造出具有遮蔽紫外线的功能性宽幅涤棉府绸产品     

Inactivation of Listeria innocua on Frankfurters by Ultraviolet Light and Flash Pasteurization

ABSTRACT:  Listeria monocytogenes , a psychrotrophic foodborne pathogen, is a recurring postprocess contaminant on ready-to-eat meat (RTE) products including frankfurters. Flash (Steam) Pasteurization (FP) and ultraviolet light (254 nm-UVC) has been shown to reduce levels of L. monocytogenes and L. innocua on frankfurters. In this study, the use of UVC light followed by FP to inactivate L. innocua, a nonpathogenic surrogate for L.monocytogenes , on frankfurters that contained sodium diacetate and potassium lactate (SDA/PL) in a pilot-plant setting was investigated. Application of UVC (1.0 J/cm²), followed by FP (0.75 s steam/121 °C) resulted in inactivation of 3.19 log L. innocua , while application of UVC (4.0 J/cm²), followed by FP (3 s steam/121 °C) resulted in inactivation of 3.89 log of L. innocua . A refrigerated storage study (8 °C) of frankfurters that contained SDA/PL that were treated with UVC followed by FP revealed the growth of L. innocua was inhibited for approximately 8 wk following application of the interventions. The use of UVC in combination with FP had little effect on frankfurter color and texture. The combination of UVC, FP, and SDA/PL was found to be an effective hurdle process for decontamination of frankfurter surfaces.     

发光二极管蓝光结合紫外线处理对鲜切杏鲍菇贮藏品质的影响

本研究采用中短波紫外线和发光二极管（light emitting diode,LED）蓝光联合处理鲜切杏鲍菇,探究光处理对鲜切杏鲍菇贮藏品质的影响。结果表明,光处理可有效保持鲜切杏鲍菇的色泽,延缓总酚、类黄酮及VC含量下降,同时抑制微生物的生长;鲜切杏鲍菇经LED蓝光结合中波紫外线（ultraviolet-B,UV-B）和短波紫外线（ultraviolet-C,UV-C）处理后,VD2的含量可达0.77 μg/100 g mw,可溶性蛋白含量在贮藏第2天较初始提高了20.85%,在贮藏第10天时还原糖含量是对照组的2.06 倍;LED蓝光结合UV-C/B处理增强了活性氧代谢、次生代谢相关酶的活力,抑制了超氧阴离子自由基（O2－·）的产生;鲜切杏鲍菇微观结构表明LED蓝光和UV-C/B光波处理均可抑制细胞壁、线粒体的降解。综上所述,LED蓝光结合UV-C/B处理可以较好地保持鲜切杏鲍菇的贮藏品质和营养价值,有效延长贮藏期。     

Nonthermal Inactivation of Soy (Glycine Max Sp.) Lipoxygenase by Pulsed Ultraviolet Light

This study investigated pulsed ultraviolet (PUV) illumination at different distances from the PUV source on soybean lipoxygenase (LOX) (0.4 mg/mL in 0.01 M Tris‐HCl buffer, pH 9) activity. Samples (5 mL) were illuminated for 1, 2, 4, 8, and 16 s at 3 distances 6, 8.5, and 11 cm from the PUV lamp's quartz window. The temperature of 33.5 ± 1.8°C was observed for the highest treatment time of 16 s at the shortest distance of 6 cm, and resulted in a 3.5 log reduction (99.95%) in initial LOX activity. Illumination time and distance from the lamp significantly (P ≤ 0.05) affected LOX inactivation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) was performed on treated LOX samples and further protein profile for treated LOX filtrate (≤10 kDa), was analyzed by reverse phase high‐performance liquid chromatography (RP‐HPLC). The protein profile analysis revealed that LOX protein degradation was influenced significantly (P ≤ 0.05) by PUV illumination time.     

The Effect of Ultraviolet Light on Microbial Inactivation and Quality Attributes of Apple Juice

Non-thermal technologies such as UV irradiation can offer advantages for minimal processing of transparent beverages. In this study, reconstituted apple juice was exposed to UV light in a continuous laboratory scale system at energy dosages ranging from 2.66 to 53.10 J/cm² by changing the exposure time. Treated juices were then evaluated for microbial inactivation and selected physical and chemical attributes. Product quality was further assessed by sensory evaluation using a 30-member consumer panel. Microbiological analysis was performed by inoculating apple juice with Escherichia coli K12 and Listeria innocua and microbial numbers were counted pre- and post-processing. UV energy levels did not affect pH, °Brix, or total phenols content, but decreased non-enzymatic browning (p < 0.01) and antioxidant capacity (p < 0.05) compared to unprocessed juice. A colour-lightening effect was noted with increasing energy dose. All UV treatments applied (2.66 J/cm² and above) resulted in a reduction below the detection level (<1 log cfu/ml) for both E. coli and L. innocua in apple juice. Sensory evaluation showed that samples treated with energy dosages up to 10.62 J/cm² were comparable to the control in terms of acceptability, though higher dosages produced adverse effects in terms of flavour and colour. Based on these results, UV treatment with low energy dosages could represent a valid alternative to thermal processing to eliminate pathogenic microorganisms while maintaining quality in reconstituted apple juice.     

Effect of Processing Under Ultraviolet Light on the Shelf Life of Fresh-Cut Cantaloupe Melon

ABSTRACT: The effect of processing cantaloupe melon under ultraviolet-C (UV-C) radiation on storage properties of the cut fruit at 10 °C was compared with post-cut UV-C fruit treatment and the untreated control. Cutting fruit under UV-C light induced a hypersensitive defense response that resulted in increased accumulation of ascorbate peroxidase relative to the other 2 treatments. Fruit processed under UV-C radiation had the lowest esterase activity throughout the storage period. Lipase activity was higher in post-cut treated fruit than fruit processed under UV-C light and the control fruit. Lipase activity, however, decreased rapidly in fruit processed under UV-C and was undetectable after 7 d of storage. Human sensory aroma evaluation indicates reduced rancidity, and instrumental texture measurements suggested improved firmness retention in fruit cut under UV-C radiation. The treatment also reduced respiration during cut fruit storage. UV-C was effective in reducing yeast, mold, and Pseudomonas spp populations in both treatments. Fresh-cut pieces from whole melon cut under UV light had lower populations of aerobic mesophilic and lactic acid bacteria relative to the control and post-cut treated pieces. Results indicate that while post-cut application of UV improved shelf life of cut cantaloupe melon, cutting fruit under UV-C radiation further improves product quality.     

响应面法优化切片腊肉的脉冲强光-紫外照射杀菌工艺

采用脉冲强光-紫外照射处理方法对腊肉的保鲜效果进行研究,通过响应面法分析优化切片腊肉杀菌率的影响因素。在单因素试验基础上,选取腊肉切片厚度、脉冲强光-紫外照射距离、闪照时间为影响因素,以杀菌率为响应值,用Box-Behnken试验设计建立响应面分析模型。结果表明:腊肉切片厚度为3 mm、腊肉距离脉冲强光光源6 cm、距离紫外光源15 cm、闪照时间为5 min时,腊肉样品的杀菌率可达99.67%,与模型拟合程度高,杀菌效果显著。     

臭氧和紫外降解面粉中的DON及对面粉品质的影响

为降低面粉DON含量,用臭氧及紫外线处理受污染的面粉,研究处理条件对降解效果的影响,对比处理前后面粉的蛋白含量、湿面筋含量和白度值并通过MTT法评价降解产物安全性。研究表明,在臭氧浓度45.00 mg/L,水分含量为16.00%的条件下处理DON污染面粉60 min,初始DON含量为2.35、2.84、4.09和4.95 mg/kg的面粉DON降解率分别为46.59%、40.71%、38.96%和35.40%;在紫外照射强度1200μW/cm2,水分含量12.00%的条件下处理DON污染面粉60 min,相同初始含量的DON降解率为39.89%、40.32%、36.68%和30.32%。两种处理后面粉蛋白质含量、湿面筋含量和白度等理化指标均无显著变化(p0.05)。MTT实验表明:DON对LO2有很强的细胞毒性,给药48h后细胞活性降低62.02%,相同DON浓度的紫外降解产物使细胞活性降低17.50%,臭氧降解产物则使细胞活性仅下降2%(p0.05)。本研究使用的方法可在短时间内有效降低面粉中DON含量,对面粉品质无显著影响,两种方法的降解产物对LO2细胞毒性均显著下降(p0.01)。     

Effect of Pulsed Ultraviolet Light and High Hydrostatic Pressure on the Antigenicity of Almond Protein Extracts

The efficacy of pulsed ultraviolet light (PUV) and high hydrostatic pressure (HHP) on the IgE binding to the almond extracts was studied using sodium dodecyl sulfate polyacrylamide-gel electrophoresis, Western blot, and enzyme-linked immunosorbent assay (ELISA) probed with human plasma containing IgE antibodies to almond allergens and a polyclonal antibody against almond major protein. Crude almond protein extracts were treated with PUV (3 pulses/s, 10 cm from lamp) for 0.5, 1, 2, 3, 4, 6, 7, and 10 min. In comparison, boiling treatments were also carried out. The HHP treatments were conducted at 600 MPa for 5, 15, and 30 min at three temperatures of 4 °C, 21 °C, and 70 °C. Western blots and indirect ELISA demonstrated a reduction in the levels of allergens and IgE binding in PUV-treated extracts at 7 min, which was found to be the optimal time for PUV exposure. Boiling was not as effective as PUV in reducing the overall IgE-binding of the almond extracts. Unlike PUV, HHP did not affect the allergen levels and IgE binding under the conditions tested.     

Stability of the Stevia‐Derived Sweetener Rebaudioside A in Solution as Affected by Ultraviolet Light Exposure

Rebaudioside A is a natural noncaloric high‐potency sweetener extracted from the leaves of Stevia rebaudiana. With rebaudioside A use increasing in foods, understanding the factors affecting its stability is necessary. This project evaluated the degradation rate constants of rebaudioside A in water, 0.1 M phosphate buffer, and 0.1 M citrate buffer at pH 3 and 7 as a function of ultraviolet (UV) light intensity (365 nm, 0 μW/cm² for dark conditions, 27 μW/cm² for low intensity, and 190 μW/cm² for high intensity) at 32.5 °C. Rebaudioside A stability was adversely affected by light exposure. The pseudo‐1st‐order degradation rate constants increased significantly (P < 0.05) with increasing light intensity in all solutions. Under dark conditions, rebaudioside A in phosphate buffers was more susceptible to breakdown than in water and citrate buffers at both pH levels. However, exposure to UV light resulted in rebaudioside A degradation occurring approximately 10 times faster in citrate than in phosphate buffers at both pH levels. The sensitivity of rebaudioside A to UV light was greater in citrate buffers than in water or phosphate buffers. The use of light‐protective packaging for beverages containing rebaudioside A will improve its stability.     

Inactivation of Escherichia Coli O157:H7 and Salmonella Enterica on Blueberries in Water Using Ultraviolet Light

Ultraviolet light (UV) has antimicrobial effects, but the shadowing effect has limited its application. In this study, a novel setup using UV processing in agitated water was developed to inactivate Escherichia coli O157:H7 and Salmonella on blueberries. Blueberries were dip‐ or spot‐inoculated with E. coli or Salmonella. Blueberries inoculated with E. coli were treated for 2 to 10 min with UV directly (dry UV) or immersed in agitated water during UV treatment (wet UV). E. coli was most easily killed on spot‐inoculated blueberries with a 5.2‐log reduction after 10‐min wet UV treatment. Dip‐inoculated blueberries were the most difficult to be decontaminated with only 1.6‐log reduction after 10‐min wet UV treatment. Wet UV treatment generally showed higher efficacies than dry UV treatment, achieving an average of 1.4 log more reduction for spot‐inoculated blueberries. For dip‐inoculated blueberries, chlorine washing and UV treatments were less effective, achieving <2 log reductions of E. coli. Thus, the efficacy of combinations of wet UV with sodium dodecyl sulfate (SDS), levulinic acid, or chlorine was evaluated. Inoculated blueberries were UV‐treated while being immersed in agitated water containing 100 ppm SDS, 0.5% levulinic acid or 10 ppm chlorine. The 3 chemicals did not significantly enhance the wet UV treatment. Findings of this study suggest that UV treatment could be used as an alternative to chlorine washing for blueberries and potentially for other fresh produce.     

Ultraviolet Light (254 nm) Inactivation of Listeria monocytogenes on Frankfurters That Contain Potassium Lactate and Sodium Diacetate

ABSTRACT:  Listeria monocytogenes , a psychrotrophic foodborne pathogen, is an occasional postprocess contaminant on ready-to-eat meat (RTE) products including frankfurters. Ultraviolet C light (UVC) is an FDA-approved technology for the decontamination of food surfaces. In this study, the ability of UVC to inactivate L. monocytogenes on frankfurters that contained potassium lactate (PL) and sodium diacetate (SDA), either before or after packaging, was investigated. UVC irradiation of frankfurters that were surface-inoculated with L. monocytogenes resulted in a 1.31, 1.49, and 1.93 log reduction at doses of 1, 2, and 4 J/cm², respectively. UVC treatment had no effect on frankfurter color or texture at UVC doses up to 4 J/cm². Frankfurter meat treated with UVC doses up to 16 J/cm² did not increase mutagenesis in bacterial or human cells, either with or without exogenous metabolic activation. UVC treatment of single-layer frankfurter packs at a dose of 2 J/cm² resulted in a 0.97 (± 0.14) log reduction of L. monocytogenes . Following 8 wk of refrigerated storage L. monocytogenes levels decreased by only 0.65 log in non-UVC-treated frankfurter packs compared with 2.5 log in the UVC-treated packs. Because the numbers of L. monocytogenes associated with contaminations of ready-to-eat meats are typically very low, the use of UVC in combination with potassium lactate and sodium diacetate has the potential to reduce the number of frankfurter recalls and foodborne illness outbreaks.     

紫外光固化聚氨酯的研究

介绍两种不同的聚氨酯预聚物合成工艺，并对它们的涂层作紫外光辐射试验，试验得到的温度、辐射距离和固化时间等参数对生产优质涂料具有指导意义。