食品物流工程类毕业外文文献翻译@中英文翻译@外文翻译

文献翻译 （ 20*届本科） 学 院： 专 业： 班 级： 姓 名： 学 号： 指导教师： 20*年 5 月 Emerging technologies for keeping microbial and sensory quality of minimally fresh processed fruits and vegetables The emphasis in post-harvest fruit protection against quality attributes losses, physiological disorders, diseases and insects has shifted from using agro-chemicals to various alternative techniques, including biological control, cultural adaptations and physical methods such as controlled atmosphere (CA), MAP and irradiation. Given the restrictions of chemical use in plant foods and because many of them cause ecological problems or are potentially harmful to humans and may be withdrawn from use, the advantage of these alternative techniques is that no chemicals are involved (Arts, 1995； Graham and Stevenson, 1997； Reddy et al., 1998； Mathre et al., 1999； Sanz et al., 1999； Daugaard, 2000； Harker et al., 2000； Marquenie et al., 2003). Additionally, preservation techniques are becoming milder in response to demands of consumers for higher quality, more convenient foods that are less heavily processed and preserved and less reliant on chemical preservatives (Abee and Wounters, 1999). The unique way to assure microbial and sensory quality of minimally fresh processed plant products relies on refrigerated storage and distribution, although combination of refrigeration and subinhibitory preservation techniques could prolong their shelf-life. As mentioned above, many non-conventional methods are now being investigated； however, there are some limitations to their application since some methods are not applicable to fresh-cut fruits and vegetables because of damage to plant tissue but only to liquid foods such as fruit juices (Carlin and Nguyen-the, 1997). Therefore, in this section those techniques that can be used to preserve fresh processed plant foods will be revised. The most critical step in the production chain of minimal fresh processing of fruits and vegetables is washing-disinfection. For this reason, special attention to the alternative sanitizing agents as well as the new technologies for disinfection of these commodities will be given. To develop or improve washing and sanitizing treatments, special attention should be paid to the compatibility of treatments with commercial practices, cost, absence of induced adverse effects on product quality and the need for regulatory approval and consumer acceptance (Sapers, 2001). Some alternatives to sanitizing agents are: O3, ClO2, peracetic acid (about 90100 ppm), H2O2, organic acids (acetic, lactic, citric, malic, sorbic and propionic acids at 300500 mg/ml), electrolysed water, radio frequency, hot water treatments and UV-C radiation (Adams et al., 1989； Masson, 1990； Castaer et al., 1996； Toms-Barbern et al., 1997； Delaquis et al., 1999, 2000, 2004； Sapers, 2001； Suslow, 2002； Jacxsens, 2002； Aguayo, 2003； Allende, 2003). 1. Hydrogen peroxide Treatments of hydrogen peroxide (H2O2) seem to be a promising alternative to chlorine for disinfecting minimally fresh processed vegetables (Soliva-Fortuny and Martn-Belloso, 2003). H2O2 is generally recognized as safe (GRAS) for some food applications, but has not yet been approved as an antimicrobial wash. It does not produce residues since it is rapidly decomposed by the enzyme catalase to water and O2 (Sapers, 2001). Various experimental antimicrobial applications of H2O2 for foods have been described, including preservation of vegetable salads, berries and fresh-cut melons (Hagenmaier and Baker, 1997) since it reduces microbial populations and extends the shelf-life without causing loss of quality. Sapers and Simmons (1998) recommended its use for fresh-cut melon as it extended the shelf-life for 45 days in comparison to chlorine treatments. However, they demonstrated that H2O2 is injurious to some commodities, causing bleaching of anthocyanins in mechanically damaged berries. H2O2 vapour delayed or reduced the severity of bacterial soft rot in fresh processed cucumber, green bell pepper and zucchini, but no effect on spoilage of fresh-cut broccoli was found (Hagenmaier and Baker, 1997). Additionally, an extended shelf-life was found in fresh processed cucumbers, green bell peppers and zucchini after washing in a 510 per cent solution of H2O2 for 2 min (Sapers and Simmons, 1998). It means that the applicability of H2O2 to a broad range of minimally fresh processed vegetables should be determined, especially with commodities that are subject to rapid spoilage. 2. Acidic electrolysed water This is a new disinfectant technique for fresh produce that has been shown to be efficient due to its antimicrobial and antiviral activities for fruit and vegetables (Izumi, 1999； Koseki and Itoh, 2000). Electrolysis of water containing a small amount of sodium chloride generates a highly acidic hypochlorous acid solution containing 10100 ppm of available chlorine. Koseki et al. (2001) found that acidic electrolysed water (pH 2.6, oxidation reduction potential, 1140mV； 30 ppm of available chlorine) reduced viable aerobes in shredded lettuce by 2 log cfu/g within 10 min, showing a higher disinfectant effect than ozonated water. They reported that the use of this new technique could be applicable for food factory hygiene, meaning that the use of acidic electrolysed water at home or restaurant kitchen just before eating fresh fruits and vegetables could prevent poisoning. According to this, Park et al. (2002) reported population reductions on lettuce leaves exceeding 2.49 log units for E. coli O157:H7 and L. monocytogenes and Horton et al. (1998) reported population reductions of E. coli O157:H7 on apples of 3.74.6 log units cfu/g. However, Izumi (1999) only found 1 log unit cfu/g reduction in the microbial population of fresh-cut vegetables. 3. Chlorine dioxide Chlorine dioxide (ClO2) is a strong oxidizing agent (about 2.5 times the oxidative capacity of chlorine) having a broad biocide efficacy (Singh et al., 2002), including a good biofilm penetration. To date, the FDA (USFDA, 1998) has allowed the use of aqueous ClO2 in washing of uncut and unpeeled fruit and vegetables. However, ClO2 is unstable and it must be generated on-site and can be explosive when concentrated (Jacxsens, 2002). Zhang and Farber (1996) found that the initial microbial load decreased by 1 log cycle of cfu/g for shredded lettuce inoculated with L. monocytogenes at levels of 5 mg/l ClO2 in aqueous solution. However, Reina et al. (1995) found that bacterial populations present on fresh processed cucumbers were not greatly influenced by ClO2 treatment, even at concentration of 5.1 mg/l. More recently, Singh et al. (2002) found that increasing the concentration of ClO2 in deionized water (5 mg/l for 1 and 5 min) resulted in a decrease in E. coli O157:H7 population on lettuce and baby carrots in comparison to washing with deionized water (control) for the same period. Increasing the washing period from 1 to 15 min with aqueous ClO2 (5 mg/l) showed no significant reduction in the population of E. coli O157:H7 on shredded lettuce. However, after washing baby carrots a reduction in E. coli O157:H7 was found. 4. Organic acids Several organic acids have been tested as alternative disinfectants to sanitize fresh-cut vegetable surfaces (Hilgren and Salverda, 2000). They may retard and/or prevent the growth of some microorganisms (Beuchat, 1998). Their antimicrobial activity is not generally due to killing of the cells but they affect the cells ability to maintain pH homeostasis, disrupting substrate transport and inhibiting metabolic pathways (Seymour, 1999). Peracetic acid has been recommended for treatment of process water (Hilgren and Salverda, 2000)； however, population reductions for aerobic bacteria, coliforms, yeast and moulds on fresh-cut celery, cabbage and potatoes, treated with 80 ppm peracetic acid, were less than 1.5 log units cfu/g (Forney et al., 1991). Wright et al. (2000) obtained a 2 log units cfu/g reduction in apple slices inoculated with E. coli O157:H7 using 80 ppm peracetic acid, with an interval of 30 min between inoculation and treatment. On the other hand, Wisniewsky et al. (2000) found a reduction of less than 1 log unit cfu/g at the same concentration but in an interval of 24 h. Citric acid has been proposed as a very good coadjutant to the washing of fresh-cut fruit and vegetables due to its antibrowning power. It is a phenolase Cu-chelating agent and the inhibition of PPO was attributed to its chelating action (Jiang et al., 1999). Santerre et al. (1988) reported that application of citric acid can prevent browning of sliced apple thus extending shelf-life and it was shown that the combination of citric acid and ascorbic acid exhibited even more beneficial effects (Pizzocaro et al., 1993). Additionally, Jiang et al. (2004) found that the application of citric acid was effective in extending shelf-life and maintaining the quality of fresh-cut Chinese water chestnut slices during storage. 5. Ozone Ozone (O3) is a strong oxidant and potent disinfecting agent and, when it is applied to food, it leaves no residues since it decomposes quickly. The biocide effect of O3 is caused by a combination of its high oxidation potential, reacting with organic material up to 3000 times faster than chlorine (EPRI, 1997). Even though it is new for the USA, it has been utilized in European countries for a long time (Guzel-Seydima et al., 2004). For instance, it has been commonly used as a sanitizer in water treatment plants since the early 1900s (Gomella, 1972) and also for disinfection of swimming pools, sewage plants, disinfection of bottled water and prevention of fouling of cooling towers in Europe (Gomella, 1972； Rice et al., 1981； Legeron, 1982； Schneider, 1982； Echols and Mayne, 1990； Costerton, 1994； Videla et al., 1995； Strittmatter et al., 1996). In 1997, an expert panel decreed that O3 was a GRAS substance for use as a disinfectant or sanitizer for foods when used in accordance with good manufacturing practices in the USA (Suslow, 2003) and it has now been approved for use as a disinfectant or sanitizer in foods and food processing in the USA (USDA, 1997, 1998). The bactericidal action of O3 has been studied and documented on a wide variety of organisms, including those that are resistant to chlorine, extending the shelf-life of a number of fruit and vegetables (Fetner and Ingols, 1956； Norton et al., 1968； Rice et al., 1982； Foegeding, 1985； Ishizaki et al., 1986； Foegeding and Busta, 1991； Restaino et al., 1995； Beuchat, 1998； Richardson et al., 1998； Aguayo, 2003). In fact, it has been proven that O3 is suitable for washing and sanitizing solid food with intact and smooth surfaces (e.g. fruit and vegetables) and ozone-sanitized fresh produce has recently been introduced in the USA market. The use of O3 to sanitize equipment, packaging materials and the processing environment is currently being investigated (Kim et al., 2003). The modus operandi of O3 implicates the destruction of microorganisms by the progressive oxidation of vital cellular components. The bacterial cell surface has been suggested as the primary target of ozonation (Guzel-Seydima et al., 2004). Khadre and Yousef (2001) compared the effects of O3 and H2O2 against foodborne Bacillus spp. spores and found that O3 was more effective than H2O2. In shredded lettuce treated with O3, Kim et al. (1999) reported that bubbling O3 gas (49 mg/l, 0.5 l/min) in a lettuce-water mixture decreased the natural microbial load by 1.51.9 log unit cfu/g in 5 min. As a consequence, a number of patents have been issued for using O3 to treat fruit and vegetables. However, the results obtained by Singh et al. (2002) have shown that treatment with ozonated water (5.2 mg/l) did not result in any significant reduction in E. coli O157:H7 populations during 115 min of washing in shredded lettuce, although they found a reduction in microbial counts on baby carrots after 10 min exposure to 5.2 mg/l ozonated water. The reduced efficacy of ozonated water during lettuce washing might be due to more O3 demand of organic material in the medium as it was also found in melon fresh-cut pieces (Aguayo, 2003). It was shown that the use of O3 in the storage of vegetable products could have detrimental effects, as happened in some berries with very thin skin which can be easily penetrated by O3, oxidizing the fruit (Norton et al., 1968； Rice et al., 1982). The antimicrobial efficacy can be enhanced considerably when ozonation is combined with other chemical (e.g. H2O2) or physical (e.g. UV-C radiation) treatments. Mechanical action is also needed as a means to dislodge microorganisms from the surface of the food and expose them to the action of the sanitizer (Kim et al., 2003). 6. Hot water treatments Heat preservation is one of the oldest forms of preservation known to man and has the potential to provide barriers to reduce microorganisms and inhibit enzyme activity, but this treatment is incompatible with fresh processed plant food since heat is associated with destruction of flavour, texture, colour and nutritional quality (Orsat et al., 2001). However, hot water treatments used to reduce or eliminate pathogens offer an alternative means to control the quality deterioration of fresh fruit and vegetables, as well as a means of enzyme inactivation (Bolin and Huxsoll, 1991). These mild heat treatments consist of subjecting the products to temperatures of 5090C for periods of time not exceeding 15 min. Loaiza-Velarde et al. (1997) reported that dipping lettuce in water at 4555C would extend the shelf-life and visual quality of minimally fresh processed lettuce by inhibiting the activity of PAL, which is the enzyme that initiates biosynthesis of phenolic compounds that leads to visible discoloration along the cut edge of the lettuce leaf (Lpez-Glvez et al., 1996). Additionally, Li et al. (2001) suggest that heat (50C) treatment combined with 20 mg/l free chlorine for 90 s may have delayed browning and reduced initial populations of some groups of microorganisms naturally occurring on iceberg lettuce, but enhanced microbial growth during subsequent storage due to tissue damage. Delaquis et al. (1999, 2000) found a reduction of 2 log cfu/g in initial microbial load in lettuce washed with chlorinated water (100_l/l) at 47C for 3 min, compared to washing at 4C. However, in 2004, Delaquis et al. found that comparison between lettuce washed at 4C and 50C revealed that disinfection of the lettuce was improved by heat, although the difference in total microbial populations was only 1 log cfu/g. The application of mild heat treatments is commonly by using hot air, hot water or steam. Among them, hot water is the easiest conditioning treatment since it offers a great flexibility and easiest control (Barkai-Golan and Philips, 1991). However, Orsat et al. (2001) have demonstrated that it is possible to treat carrot sticks thermally with radio-frequency energy in less than 2 min at an internal temperature of 60C, to reduce the microbial load before packaging while minimizing the detrimental effects on the sensory quality of the fresh-like product. The main difference in using this treatment is that in radio-frequency heating, the energy is absorbed directly within the material, the heating is rapid and uniform throughout the material and the technology is relatively simple to adapt to an existing processing line. 保持 微创 新鲜 已 加工果蔬的微生物和感官质量的新兴技术 （英文文献中文译稿） 收获后水果对质量损失、生理病变、虫害等的保护的重点已经从使用农药转变为各种替代技术，包括生物控制、文化适应和物理方法如控制气氛、 MAP 和辐射。因为化学品会引起生态问题并对人体产生潜在危害，所以在农产品中使用有限制或禁止使用， 这些替代技术的优点是不涉及化学品 。此外，保护技术正响应消费者对高质量、 不那么严重处理和维护 并 减少对化学防腐剂依赖方便食品 的需求。 虽然亚抑菌保鲜和冷藏 技术的组合可以延长 农产品的 保质期 ，但保证微生物和微创新鲜已加工农产品的感官质量的独特途径还是依靠冷藏库和配送。 如上所述，许多非传统的方法正在研究，然而由于会 损害植物组织 ，所以 有些方法并不适用于鲜切水果和蔬菜 还有液态食品比如果实，因此应用有一些局限性。所以，这部分用来保存新鲜以加工的农产品的技术将被修改。 果蔬 的最小新鲜 加工 在 生产链 中 最关键的步骤是清洗消毒。 基于这个原因，要特别注意选择对这些产品消毒药物和新兴技术。为了 发展改善清洗和消毒处理 ，需要特别注意在产品质量和 监管机构的批准和消费者接受 上的商业惯例、成 本、缺乏引起的不良影响的兼容处理。 一些消毒药物的选择是：臭氧，二氧化氯，过氧乙酸（约 90-100 ppm 的），过氧化氢，有机酸（醋酸，乳酸，柠檬酸，苹果酸，在 300-500毫克 /毫升山梨酸和丙酸），电解水，无线电频率，热水治疗和 UV - C 辐射 等。 1. 过氧化氢 过氧化氢（ H2O2）的使用似乎是 替代氯消毒微创新鲜 已加工 蔬菜 的比较好的方法。过氧化氢是一些食品应用中普遍认为安全的，但尚未被批准为抗菌洗剂。它不会产生残留， 因为它 会 迅速分解酶的过氧化氢酶的水和氧气 。对食品使用的各种实验的抗菌所用的过氧化氢， 包括 蔬菜沙拉，新鲜浆果和切瓜保存 ，因为它减少了微生物群并延长货架期而不造成质量损失。 Sapers 和 Simmons（ 1998）认为在鲜切瓜上使用过氧化氢比用氯来消毒要延长 4 至 5 天的货架期。但是，他们也表明过氧化氢对某些产品有损害，会造成浆果的机械损害而漂白了花青素。过氧化氢的蒸汽延缓或减少了在新鲜已工的黄瓜、青椒和西葫芦中细菌性软腐病的严重性，但发现对鲜切青花菜没有损坏效果。此外，度为 5%至 10%的过氧化氢冲洗2 分钟之后，发现可以延长黄瓜、青椒和西葫芦的货架期。这就意味着，在微创新鲜已加工蔬菜的范围中已确定过氧化 氢是适用的，特别是容易迅速腐烂的商品。 2. 酸性电解水 由于 对 果蔬活动 能 抗菌和抗病毒 ，这是一个 新的已被证明 对 新鲜农产品是有效的消毒技术 。含有少量氯化钠的电解水生成含有 10-100 ppm 的有效氯的高酸度的次氯酸。 Koseki 等 发现酸性电解水（ pH值 2.6，氧化还原电位， 1140mV，有效氯 30 ppm） 在 10 分钟内生菜丝的可行需氧菌 2 log cfu/g，表明了比臭氧水杀菌有更好的效果。 他们报告说，这一新技术的使用可 适用 于食品厂 的 卫生，这意味着在家里或餐厅 厨房 吃新鲜果蔬 前使用 酸性电解水可预防中毒。 根据这个， Park 等指出生菜叶子上减少了超过 2.49 log 单位的大肠杆菌和李斯特菌，而 Horton 等指出在苹果上大肠杆菌减少了 3.7 4.6 log单位。然而， Izumi 发现在鲜切蔬菜上只减少了 1 log 单位 cfu/g 微生物种群。 3. 二氧化氯 二氧化氯（ ClO2）是一种强氧化剂（约 2.5 倍的氯氧化能力） ， 具有广泛的生物杀虫剂药效 并 包括一个良好的生物膜的渗透。 至今 ， 食品药品管理局 已经允许二氧化氯水溶液在未经切割和削皮的果蔬 的清洗 中 使用。 Zhang 和 Farber 发现，生菜丝的 最初的微生物 在接种了在 5 mg/l 的二氧化氯水溶液中的李斯特菌 后每 cfu/g 下降 1 log 周期。然而，二氧化氯是不稳定的，它必须现场及时生成，而且当集中起来后会爆炸。 然而， Reina 等 发现，细菌群体 在 新鲜 的已 处理黄瓜 上 二氧化氯处理 的 影响 并不大 ， 即使是 在 5.1 mg/l 的 浓度 中。最近， Singh 等人发现相比小胡萝卜在同一时期用去离子水（对照）清洗，增加去离子水（ 5 mg/l， 1 和 5 分钟）中二氧化氯的浓度会使生菜中的大肠杆菌减少。 将用二氧化氯（ 5 mg/l）的洗涤时间从 1 分钟增加至 5 分钟没有发现生菜丝上大肠杆菌数量的减少，但在小 胡萝卜上发现减少了。 4. 有机酸 有几种作为可选择的消毒鲜切蔬菜表面的消毒剂的有机酸已做过测试，它们 可能会延缓 并 /或预防某些微生物的生长 。它们的抗菌活性不仅能杀死一般的细胞，并且能够影响细胞的活性来维持 pH 平衡，扰乱传递并抑制底物的代谢途径。 过氧乙酸已被推荐用于水处理过程，然而对于用 80 ppm 的过氧乙酸减少 鲜切芹菜 、 白菜和土豆 上 好氧细菌 、 大肠菌群 、 酵母 菌 ，均小于 1.5 log 每单元 cfu/g。 Wright等人得出，在苹果切片用