Cigarette smoking during pregnancy.

Maternal smoking during pregnancy is associated with several adverse developmental outcomes in the offspring. These include preterm delivery, spontaneous abortion, growth restriction, increased risk of sudden infant death syndrome (SIDS), as well as long-term behavioral and psychiatric disorders. However, the underlying physiological mechanisms for these ill-effects are not fully understood. The aim of this paper is to review the animal and human data to date, linking in utero smoke exposure to negative neurodevelopmental outcomes. It is known that nicotine from cigarette smoke exerts its effects by affecting placental vasculature, and also by nicotinic acetylcholine receptor binding in fetal membranes. Thus, subsequent consequences involve a cascade of events causing not only dysregulation of the nicotinic and muscarinic, but also catecholaminergic and serotonergic neurotransmitter systems. These observations provide some insight into how smoking can impair neurodevelopment, but the long-term neurotransmitter involvement in dysregulation of emotion and attention awaits further elucidation. It is important that pregnant women are warned of the detrimental effects of smoking, and encouraged to abstain for healthy fetal development.     

肉制品加工过程中食源性致病菌交叉污染及风险评估的研究进展

肉制品加工过程中食源性致病菌容易在食物接触表面和机器设备表面发生交叉污染,导致成品存在食用风 险。国内外已有研究者采用风险评估手段评估肉制品的食用风险。本文针对2000年至今已有的肉制品加工过程中食 源性致病菌交叉污染及其模型应用研究进行了综述,介绍了肉制品加工过程中食源性致病菌的交叉污染现状和因交 叉污染导致的食源性疾病现状,简述了部分加工过程的交叉污染模型及其在风险评估领域的应用,同时对目前香肠 类和火腿类两类肉制品现有的风险评估研究进行概括,最后对将来开展肉制品加工过程中交叉污染研究和定量风险 评估提出建议和思考。建议加强肉制品加工过程中交叉污染建模研究,增强风险评估与风险管理的互动交流,完善 肉制品加工过程的风险监测,进而开展更多系统性的肉制品加工过程定量风险评估研究。     

Foodborne outbreaks in Canada linked to produce.

Examples of foodborne outbreaks traced to fresh fruits and vegetables can be found worldwide. The quantity of produce eaten per capita has been increasing steadily over the past two decades, creating a heightened potential for produce-related foodborne disease. A number of outbreaks identified during this time period were reviewed, with particular emphasis placed on incidents that have occurred in Canada. The collective information highlights the diversity of infectious agents and produce items involved, with a view to the prevention of fresh produce-related foodborne disease in the future.     

Foodborne protozoan parasites

This report addresses Cryptosporidium, Giardia, Cyclospora, and more briefly, Toxoplasma as the main parasitic protozoa of concern to food production worldwide. Other parasitic protozoa may be spread in food or water but are not considered as great a risk to food manufacture. The protozoan parasites Cryptosporidium, Giardia, and Cyclospora have proven potential to cause waterborne and foodborne disease. Toxoplasma gondii has been considered a risk in specific cases, but humans are not its primary host. Cryptosporidium and Giardia are widespread in the environment, particularly the aquatic environment, and major outbreaks of cryptosporidiosis and giardiasis have occurred as a result of contaminated drinking water. Large outbreaks of waterborne cyclosporiasis have not been identified. Cryptosporidium, Giardia, and Cyclospora have potential significance in the preparation and consumption of fresh produce and in catering practice, in which ready-to-eat foods may be served that have not received heat treatment. None of the three organisms Cryptosporidium, Giardia, and Cyclospora has been shown to be a problem for heat processed food or tap water that has undergone appropriate treatment at a water treatment works. All three are sensitive to standard pasteurisation techniques. Although humans are not a primary host for T. gondii, the potential exists for both waterborne and foodborne toxoplasmosis. Parasitic protozoa do not multiply in foods, but they may survive in or on moist foods for months in cool, damp environments. Their ecology makes control of these parasites difficult. For general control of parasitic protozoa in the food chain, the following steps are necessary: - Follow good hygienic practice in food service and catering industries.- Minimise dissemination of cysts and oocysts in the farming environment and via human waste management.- Include these microorganisms in Hazard Analysis Critical Control Point (HACCP) plans of water suppliers, industries or sectors that use fresh produce, and operations in which contaminated process or ingredient water could end up in the product (e.g., where water supplies may become contaminated).     

食品加工过程中致病菌控制的关键科学问题

致病性细菌是导致食源性疾病暴发的罪魁祸首,也是我国建立食品质量安全控制体系必须面对的重要危害.在食品加工过程中,食源性致病菌由于能够形成菌膜,进行亚致死损伤修复,调节抗性基因的表达等,从而对加工过程中的高温、高压、冷冻、脱水、光照、真空以及氧化等环境胁迫产生耐受性.此外,致病菌也能够分泌各种胞外毒力因子等,给食品安全带来极大的威胁.本文针对近年来食品加工过程中致病菌安全控制关键科学问题的研究进展进行阐述,并对未来的发展方向作展望.     

Breast milk from healthy women has higher anti-Candida properties than women with vaginal infections during pregnancy

Food Science and Biotechnology - The aim of this study was to investigate the different immunological and antimicrobial properties of breast milk from women with (W) or without (WO) vaginal yeast...     

Weight changes during pregnancy and the postpartum period.

Weight gain during pregnancy is considered a major determinant of fetal growth. Low maternal weight gain is associated with an increased incidence of low birth weight infants who are at higher risk for increased mortality. For the past twenty years, weight gain recommendations have been centered around one value (11 kg) as representative of a weight gain objective. Newer recommendations are based on what is considered optimal infant outcomes and not necessarily on maternal health considerations. These recent recommendations indicate the importance of pregravid weight in setting weight gain goals with overweight gravida advised to gain less than normal weight or underweight gravida. When confounding variables are controlled, maternal weight gain is similar in adolescents and older women. Reports on weight loss during the postpartum period indicate a high degree of variability in total weight change. In general, with current levels of weight gain, each successive birth adds about 1 kg of body weight above that normally gained with age. There is very little evidence to suggest that breast feeding as compared to other methods of infant feeding, causes body weight to return to prepregnancy levels at a faster rate.     

2005年中国食源性疾病暴发事件监测资料分析

目的研究2005年国家食源性疾病监测网覆盖地区食源性疾病暴发的趋势和特征。方法对国家食源性疾病监测网2005年报告的食源性疾病暴发资料进行统计分析。结果2005年,14个监测地区共上报485起食源性疾病暴发事件,累计发病10179人,死亡45人。在病原清楚的暴发事件中,微生物引起的食源性疾病暴发事件数和患者数最多,分别占42.4%和58.2%;有毒动植物引起的暴发事件数和患者数分别占30.3%和25.6%;化学物引起的暴发事件数和患者数分别占23.2%和9.2%。结论由微生物引起的食源性疾病是目前我国主要的食品安全问题,副溶血性弧菌是最主要的食源性致病菌。     

2004年中国食源性疾病暴发事件监测资料分析

目的分析国家食源性疾病监测网覆盖地区2004年食源性疾病的流行病学特征。方法对国家食源性疾病监测网2004年食源性疾病报告资料进行统计分析。结果2004年,13个监测地区共上报612起食源性疾病暴发事件,累计发病14980人,死亡48人。在病原清楚的事件中,微生物引起的食源性疾病暴发事件数和患者数最多,分别占47.5%和71.0%;化学物引起的暴发事件数和患者数分别占30.3%和15.2%;动植物引起的暴发事件数和患者数分别占21.5%和13.4%。副溶血性弧菌是最主要的微生物性病原。结论微生物性食源性疾病仍是全国食源性疾病监测网发现的主要公共卫生问题。     

Nutrient partitioning during adolescent pregnancy

Human adolescent mothers have an increased risk of delivering low birth weight and premature infants with high mortality rates within the first year of life. Studies using a highly controlled adolescent sheep paradigm demonstrate that, in young growing females, the hierarchy of nutrient partitioning during pregnancy is altered to promote growth of the maternal body at the expense of the gradually evolving nutrient requirements of the gravid uterus and mammary gland. Thus, overnourishing adolescent dams throughout pregnancy results in a major restriction in placental mass, and leads to a significant decrease in birth weight relative to adolescent dams receiving a moderate nutrient intake. High maternal intakes are also associated with increased rates of spontaneous abortion in late gestation and, for ewes delivering live young, with a reduction in the duration of gestation and in the quality and quantity of colostrum accumulated prenatally. As the adolescent dams are of equivalent age at the time of conception, these studies indicate that nutritional status during pregnancy rather than biological immaturity predisposes the rapidly growing adolescents to adverse pregnancy outcome. Nutrient partitioning between the maternal body and gravid uterus is putatively orchestrated by a number of endocrine hormones and, in this review, the roles of both maternal and placental hormones in the regulation of placental and fetal growth in this intriguing adolescent paradigm are discussed. Impaired placental growth, particularly of the fetal component of the placenta, is the primary constraint to fetal growth during late gestation in the overnourished dams and nutritional switch-over studies indicate that high nutrient intakes during the second two-thirds of pregnancy are most detrimental to pregnancy outcome. In addition, it may be possible to alter the nutrient transport function of the growth-restricted placenta in that the imposition of a catabolic phase during the final third of pregnancy in previously rapidly growing dams results in a modest increase in lamb birth weight.     

Couple dynamics during women's tobacco reduction in pregnancy and postpartum.

Smoking cessation during pregnancy is often temporary; many women relapse postpartum. To develop strategies for supporting successful long-term smoking cessation, we conducted a qualitative study to explore the influence of couple interactions on women's tobacco reduction within the context of pregnancy and the postpartum period. A total of 28 women who quit or reduced smoking for pregnancy and their partners were interviewed following delivery and at 3-6 months postpartum. Open-ended, individual interviews elicited the challenges posed by the women's tobacco reduction and how their partners influenced their cessation efforts. The use of constant comparative analytic strategies focusing on women's processes, experiences, and responses revealed that unquestioned expectations for pregnant women's cessation created the social context of compelled tobacco reduction. Women's engagement in tobacco reduction in this context fundamentally altered couples' previously established tobacco-related routines. The intensity of these changes varied depending on the couples' established interaction patterns with respect to tobacco (i.e., disengaged, conflictual, or accommodating) and was a source of conflict for some couples. The findings offer novel ways to understand smoking cessation during pregnancy that provide new directions for research and for tailoring smoking cessation interventions.     

Foodborne viruses: an emerging problem

Several groups of viruses may infect persons after ingestion and then are shed via stool. Of these, the norovirus (NoV) and hepatitis A virus (HAV) are currently recognised as the most important human foodborne pathogens with regard to the number of outbreaks and people affected in the Western world. NoV and HAV are highly infectious and may lead to widespread outbreaks. The clinical manifestation of NoV infection, however, is relatively mild. Asymptomatic infections are common and may contribute to the spread of the infection. Introduction of NoV in a community or population (a seeding event) may be followed by additional spread because of the highly infectious nature of NoV, resulting in a great number of secondary infections (50% of contacts). Hepatitis A is an increasing problem because of the decrease in immunity of populations in countries with high standards of hygiene. Molecular-based methods can detect viruses in shellfish but are not yet available for other foods. The applicability of the methods currently available for monitoring foods for viral contamination is unknown. No consistent correlation has been found between the presence of indicator microorganisms (i.e. bacteriophages, E. coli) and viruses. NoV and HAV are highly infectious and exhibit variable levels of resistance to heat and disinfection agents. However, they are both inactivated at 100 degrees C. No validated model virus or model system is available for studies of inactivation of NoV, although investigations could make use of structurally similar viruses (i.e. canine and feline caliciviruses). In the absence of a model virus or model system, food safety guidelines need to be based on studies that have been performed with the most resistant enteric RNA viruses (i.e. HAV, for which a model system does exist) and also with bacteriophages (for water). Most documented foodborne viral outbreaks can be traced to food that has been manually handled by an infected foodhandler, rather than to industrially processed foods. The viral contamination of food can occur anywhere in the process from farm to fork, but most foodborne viral infections can be traced back to infected persons who handle food that is not heated or otherwise treated afterwards. Therefore, emphasis should be on stringent personal hygiene during preparation. If viruses are present in food preprocessing, residual viral infectivity may be present after some industrial processes. Therefore, it is key that sufficient attention be given to good agriculture practice (GAP) and good manufacturing practice (GMP) to avoid introduction of viruses onto the raw material and into the food-manufacturing environment, and to HACCP to assure adequate management of (control over) viruses present during the manufacturing process. If viruses are present in foods after processing, they remain infectious in most circumstances and in most foods for several days or weeks, especially if kept cooled (at 4 degrees C). Therefore, emphasis should be on stringent personal hygiene during preparation. For the control of foodborne viral infections, it is necessary to: Heighten awareness about the presence and spread of these viruses by foodhandlers; Optimise and standardise methods for the detection of foodborne viruses; Develop laboratory-based surveillance to detect large, common-source outbreaks at an early stage; and Emphasise consideration of viruses in setting up food safety quality control and management systems (GHP, GMP, HACCP).     

食源性病毒及其预防与控制

过去十年,世界范围内起源于病毒感染的食品安全事件与日俱增。由于病毒在很低感染剂量下就可能导致严重的食品安全问题,以及消费者对生鲜、快捷、安全食品的需求,引发了人们关于传统食品加工工艺对病毒作用效果的研究,并促使科学工作者开发出许多新颖的食品加工和保藏方法。本文对致病病毒的种类、特点、传播途径以及预防和控制措施进行综述,并介绍关于保藏方法减少病毒水平的最新进展。     

食品中碳纳米粒子的研究进展

碳纳米粒子又称碳量子点,因具有可调谐荧光发射、成本低廉、毒性低等优点,被广泛应用于化学、生物、药物以及食品等领域。研究发现,面包、饼干、咖啡、饮料、牛奶及加工肉制品等食品中也存在碳纳米粒子。这些碳纳米粒子可直接作为荧光探针、成像试剂等应用。作者综述了食品中碳纳米粒子的来源、性质及应用,为食品中碳纳米粒子的深入研究提供理论依据。