乳酸菌拮抗食源性致病菌的研究及应用进展

食品在生产加工、物流运输和贮存消费过程中均可能出现被食源性致病菌污染的风险,造成安全隐患,目前通过热加工、辐照、电解水和等离子体等方法来控制食品中食源性致病菌,但在食品感官、规模化应用和安全生产等方面存在部分缺点.乳酸菌因其丰富的生物活性常作为生物发酵剂和保鲜剂广泛应用于食品中,并且可在食品中拮抗致病菌.本文主要从竞争...     

非热杀菌技术在低温鸡肉制品致病菌控制中的应用研究进展

由于低温鸡肉制品具有较好的感官品质,能够保留鸡肉原有的营养,成为我国肉制品发展的一个趋势。低温鸡肉制品水分含量和pH值较高,在加工和贮藏过程中极易受到食源性致病菌的污染,影响产品的质量安全,甚至引发食源性疾病,因此采用合适的杀菌技术来解决致病菌的污染是低温鸡肉制品贮藏保鲜需要解决的关键问题。由于热杀菌技术不适合用于低温鸡肉制品的灭菌,非热杀菌技术的应用就显得尤其重要。目前,应用在低温鸡肉制品加工中的非热杀菌技术主要包括超高压、辐照、超声、低温等离子体、脉冲紫外线、脉冲电场和脉冲微波。本文主要综述以上7 种非热杀菌技术的杀菌机制以及在不同低温鸡肉制品加工应用时对致病菌的控制效果,为未来非热杀菌技术在低温肉制品加工中的应用提供参考。     

辐照技术对食源性病原菌的影响研究

食源性病原菌,指在食品加工和流通过程中引入的病原菌,是引发食源性疾病的重要因素。这些病原菌以食品作为载体进行传播,一定程度上增加了某些食源性疾病爆发的可能,而传统的控制措施抑菌效果有限,当务之急是寻求革新的食品杀菌技术。食品辐照技术作为一种高新的冷杀菌技术,具有安全、无污染等优点,近年来在保障食品质量安全方面发挥的作用也引起了社会的高度重视,关于辐照技术对食品中病原菌致死作用的系统描述相对较少。本文结合国内外关于食品辐照灭菌的研究报道,综述了辐照技术的发展、辐照技术控制食品病原菌进展、辐照杀菌机制以及影响辐照灭菌效果的主要因素,并对该技术存在的问题和未来的研究进行了探讨,以期为进一步预防和控制食源性疾病提供新的思路。     

Brazilian consumer views on food irradiation

This study investigated the consumer attitude to food irradiation in São Paulo, Brazil, through a qualitative research perspective. Three focus groups were conducted with 30 consumers, responsible for food choices and purchases. Both irradiated and nonirradiated food samples were served in the sessions to motivate the discussion and elicit the participants´ knowledge, opinions, feelings and concerns towards the irradiation process. Reactions were similar among the groups and differences between the irradiated and the nonirradiated samples were hardly perceived. When provided with positive information about irradiation and its benefits to foods and human health, many people still remained suspicious about the safety of the technology. Risk perception seemed to be related to unease and lack of knowledge about nuclear power and its non-defense use. Participants claimed for more transparency in communication about risks and benefits of irradiated foods to the human health, especially with respect to the continued consumption.Industrial relevanceIrradiation is an emerging food processing technology, which has been gaining interest by food technologists, producers and manufacturers all over the world in the last decades. Irradiation is suitable for disinfestation, microorganism load reduction or sterilization, assuring the safety, as well as having benefits in the shelf-life of foodstuffs.Food irradiation is approved in many countries and its use in food processing is endorsed by several reputed authorities, such as FAO and USDA. Despite the approval and recommendation, this technology still remains underutilized not only in Brazil, but also in other countries. The main reason appears to be the consumer concerns and doubts about the use of radiations in food processing. To develop communication strategies in promotion of irradiated foods it is necessary to investigate consumer attitudes, knowledge, opinions, as well as fears, with respect to the use of radiation in food processing.It is well-known that consumer views on technology may vary from a culture to another. So, findings from consumer research in a country may certainly not reflect the consumer views in other countries. In this sense, Brazilian studies focused on consumer views on food irradiation are necessary to gain understanding on how the local market accepts the technology. Brazil is one of the most important food producers in the world and an emerging consumer market with a population of about 184 million people. Food irradiation is regulated in Brazil since 1973, but to date only a few food ingredients are subjected to irradiation. The wide use of irradiation in food processing would favor Brazilian producers in the quality and safety assurance of food products, both for the local market and for exports.     

Irradiation Applications in Dairy Products: a Review

The demand for raw and fresh dairy products with the desired organoleptic characteristics and health benefits led to research in non-thermal processing technologies aiming to retain all the product qualities and nutrients. Irradiation is an emerging non-thermal technology used in destroying micro- and macroorganisms that might exist in food by exposure to either gamma (γ) rays from radioactive isotopes (cobalt⁶⁰ or caesium¹³⁷) or an electron accelerator (electron beam or X-radiation) under a controlled environment. With the endorsement of many international food and health organisations such as the Food and Agriculture Organization (FAO) and World Health Organization (WHO), irradiation is becoming more widely researched as a process to maintain quality, improve safety and reduce quarantine and post-harvest loss. Irradiation has the potential for allergenicity reduction and the provision of a sterile diet for immunocompromised patients. Unlike other food categories, the use of irradiation as a preservative technique on dairy products has received little attention due to the complexity of the product varieties. Whilst being accepted in some countries, the adoption of irradiation as an alternative measure of treating and preventing potential problems in the food chain faces strict opposition in many countries. In this review, the focus is on the radiation processing as an emerging technology and its specific application on dairy products.     

Opportunities and challenges in pulsed electric field processing of dairy products

Consumer demand and current market conditions warrant investigation of dairy processing technologies that can deliver improved product quality and stability and reduced energy use during processing, without compromising product and process safety. One candidate technology for the extension of shelf-life in dairy products is pulsed electric field (PEF) processing. PEF is considered to be an effective, non-thermal intervention that appears to hold some promise. Research on the application of PEF to control spoilage and pathogenic microorganisms and enzyme systems in dairy products spans a wide array of processing equipment and reaction conditions. PEF has been reported to effectively reduce the numbers of both pathogens and spoilage organisms in milk; however, there is a high degree of variability between studies. The application of PEF in combination with lower temperature thermal processing can deliver comparable reductions in microbial load without significant detrimental effects to the sensory and physico-chemical properties of food products.     

Ultraviolet processing of liquid food: A review: Part 2: Effects on microorganisms and on food components and properties

The effectiveness of ultraviolet irradiation in inactivating microorganisms has been known for decades. Nevertheless, in the processing of foodstuff other important issues must be considered, such as organoleptic or nutritional properties preservation. Ultraviolet irradiation constitutes an alternative to thermal treatment that is being studied and developed to obtain a better final product sensory quality, but without neglecting microbial safety. Moreover, it has been proved that this technology can be useful to decompose some toxins that are not affected by thermal processing. In this piece of work, the effect of UV irradiation on all of these contaminants and components of liquid food has been reviewed.     

Microbiological safety of irradiated foods

This paper attempts to summarize relevant information on microbiological safety of irradiated foods in the light of previous reports of expert committees and current literature references. After a brief survey of the relative radiation resistance of food-borne microorganisms, the importance of microbial load for dose requirement, and the role of post-irradiation conditions, it addresses the following questions: Could selective changes in the microflora, caused by non-sterilizing radiation doses, make known pathogens more likely to occur, or bring into prominence unfamiliar pathogens? Is it probable that 'mutational' (including adaptive) changes might make pathogens more virulent, more harmful, or more difficult to recognize, and could new pathogens arise in this way? Is it possible that development of radiation-resistant strains might render the antimicrobial irradiation processes ineffective? The present survey of relevant scientific evidence related to these questions reaffirms the basic conclusion of earlier reviews, that microbiological safety of irradiated food is fully comparable with that of foods preserved by other acceptable preservation methods. Similar to other preservation processes, gains in microbiological or keeping quality attained by food irradiation can be and must be safeguarded by proper control in the food irradiation facilities and by proper care of the product before and after processing.     

MICROBIOLOGICAL CONSEQUENCES OF MINIMALLY PROCESSED FRUITS AND VEGETABLES

Microbiology is an important factor in the quality of minimally processed fruits and vegetables. Type of food, temperature, humidity, and use of modified atmosphere or low dose irradiation can influence the microecology of a food. Changes in the microbial ecology can likewise influence the ultimate safety and overall quality of fruits and vegetables. Therefore, food scientists must consider the microbiological consequences of all practices involved in production, processing, and delivery of these products.     

乳酸菌拮抗食源性致病菌研究进展

食品中致病菌是引起人类食源性疾病等食品安全问题主要因素之一。乳酸菌通过生态位竞争、形成酸性环境和产生各种代谢产物对食品中致病菌具有较强的拮抗作用。本文对乳酸菌生物保护剂的拮抗机制、作用的特点和优势,乳酸菌对各类食源性致病菌的拮抗作用研究以及在乳制品、肉制品、海产品和果蔬制品中的应用进行综述,为充分挖掘乳酸菌资源,利用乳酸菌生物保护剂控制食品中致病菌提供借鉴与参考。      

GAMMA IRRADIATION ON FROZEN AND PACKAGED HEADED SHRIMP

The objective of this work was to evaluate the effects of γ irradiation (0, 2, 4 and 6 kGy doses), applied on frozen and packaged headed shrimps, on pathogenic Vibrio cholerae O1 and Salmonella enteritidis bacteria, as well as on some of the physical and sensory characteristics of this kind of food. The 6 kGy dose was highly efficient in inhibiting V. cholerae O1 and S. enteritidis and in decreasing lipid oxidation in shrimps compared with the nonirradiated product. Shrimp texture was not affected by any of the irradiation doses studied, but the lightness of the surface color increased in shrimps irradiated with 6 kGy compared with those irradiated with 2 kGy. Shrimps irradiated with 6 kGy showed lower overall acceptability than those irradiated with 2 kGy or were nonirradiated. The application of γ irradiation in doses up to 6 kGy on frozen and packaged headed shrimps could improve the microbiological quality of this commodity.

PRACTICAL APPLICATIONS

The use of γ irradiation has the potential to ensure safety effectively by inactivating bacteria, increasing shelf life and maintaining food quality without significant chemical changes in the food matrix. Besides, this process can be applied to frozen and packaged products. Thus, irradiation of frozen and packaged shrimps could benefit the local processing industry, which could offer the international market a high-quality product, with an additional safety treatment.     

Approaches for reducing Salmonella in pork production

Salmonellosis is an important disease in humans and is associated with contaminated food, including pork products. Salmonella infection is invasive in humans, but it usually remains latent within the swine population, creating reservoirs for carcass contamination. Although abattoirs implement stringent procedures during carcass processing, some raw pork products still have Salmonella contamination. To reduce the presence of Salmonella, a dynamic picture of the pork production chain is needed that includes management practices aimed at health and welfare of swine and practices within swine operations that affect the environment and community health. Swine practices indirectly influence the spread of zoonotic enteric pathogens. Pathogens in food animals can escape detection, and critical control points often are missed. Preharvest growth of swine by enhancement of normal gut flora and targeting intestinal pathogens through nonantibiotic approaches might improve food safety and reduce antibiotic residues. In light of the threat posed by multidrug-resistant pathogens, old dogma is being revisited with optimism for potential utility in promoting pre- and postharvest pork safety. This review includes possible approaches that can be implemented in swine operations and postslaughter during pork processing with simultaneous omission of subtherapeutic antibiotics to control Salmonella. We emphasize the vital roles of the veterinarians, pig producers, industry, food research scientists, and government guidelines for the strategic implementation of approaches to Salmonella control across the pork production and processing chains.     

非热杀菌技术在即食肉制品中的应用研究进展

即食肉制品在生产和消费环节极易受到微生物污染,严重影响其品质和安全。传统热杀菌技术虽然能有效灭活微生物,但会对即食肉制品的营养和感官品质产生不良影响。近年来,非热杀菌技术逐渐受到关注,该技术处理温度低,对食品的风味、色泽和营养成分影响较小,避免了传统热杀菌技术造成的食品品质劣变问题。目前,在即食肉制品中应用较为广泛的非热杀菌技术主要有超高压、辐照、紫外照射、脉冲光照射和冷等离子体。本文综述上述5 种非热杀菌技术对即食肉制品的杀菌作用及对其品质的影响,以期为非热杀菌技术在即食肉制品加工中的应用提供参考。     

Combined industrial processes with irradiation to assure innocuity and preservation of food products — a review

The desire to assure food safety for consumption requires better food preservation techniques. The presence of parasites, insects, mites, and micro-organisms, is an important source of problems. In this regard, irradiation is an interesting alternative to be considered to satisfy quarantine requirements, to control severe losses during transportation and commercialization, and to insure food safety. This paper reviews some potential applications of irradiation for preserving food products.     

Development of Associations and Kinetic Models for Microbiological Data to Be Used in Comprehensive Food Safety Prediction Software

Abstract: The objective of this study was to use an existing database of food products and their associated processes, link it with a list of the foodborne pathogenic microorganisms associated with those products and finally identify growth and inactivation kinetic parameters associated with those pathogens. The database was to be used as a part of the development of comprehensive software which could predict food safety and quality for any food product. The main issues in building such a predictive system included selection of predictive models, associations of different food types with pathogens (as determined from outbreak histories), and variability in data from different experiments. More than 1000 data sets from published literature were analyzed and grouped according to microorganisms and food types. Final grouping of data consisted of the 8 most prevalent pathogens for 14 different food groups, covering all of the foods (>7000) listed in the USDA Natl. Nutrient Database. Data for each group were analyzed in terms of 1st-order inactivation, 1st-order growth, and sigmoidal growth models, and their kinetic response for growth and inactivation as a function of temperature were reported. Means and 95% confidence intervals were calculated for prediction equations. The primary advantage in obtaining group-specific kinetic data is the ability to extend microbiological growth and death simulation to a large array of product and process possibilities, while still being reasonably accurate. Such simulation capability could provide vital ‘‘what if’’ scenarios for industry, Extension, and academia in food safety.     

食品加工用水微生物检测的重要性

食品加工业是用水型工业之一,水质的优劣对食品安全至关重要,对加工用水进行安全卫生控制是生产过程控制的重要环节。微生物污染是食品加工用水最主要的安全隐患之一,我国食品加工用水微生物污染风险高、概率大,每年因食品加工用水微生物污染导致的产品质量问题不在少数,给企业造成了巨大的经济损失。食品加工企业对加工用水的质量控制必不可少,尤其是加工用水的微生物检测能力会影响最终产品的安全性。企业应打破只重视原料、过程产品和最终产品微生物检测的老思路,注意监控加工用水的微生物污染情况。参加水质微生物能力验证能够加强企业实验室对生产加工用水的自我检测能力,确保检测结果的准确性和认可性,对提高产品质量和品质有促进作用。     

Phages and engineered lysins as an effective tool to combat Gram-negative foodborne pathogens

One of the biggest challenges faced by food producers is ensuring microbiological safety. Despite strict criteria for food products, foodborne diseases are a global problem and pose a real risk to consumers. Therefore, it is necessary to identify new and more effective methods for eliminating pathogens from food and the food processing environment. According to the European Food Safety Authority (EFSA), the most common foodborne diseases are caused by Campylobacter, Salmonella, Yersinia, Escherichia coli, and Listeria. Out of the five listed, four are Gram-negative bacteria. Our review focuses on the use of bacteriophages, which are ubiquitous bacterial viruses, and bacteriophage endolysins to eliminate Gram-negative pathogens. Endolysins cleave specific bonds within the peptidoglycan (PG) of the bacterial cell, causing the cell to burst. Single phages or phage cocktails, which are, in some instances, commercially available products, eliminate pathogenic bacteria in livestock and various food matrices. Endolysins have matured as the most advanced class of antibacterial agents in the clinical sector, but their use in food protection is highly unexplored. Advanced molecular engineering techniques, different formulations, protein encapsulation, and the addition of outer membrane (OM) permeabilization agents enhance the activity of lysins against Gram-negative pathogens. This creates space for groundbreaking research on the use of lysins in the food sector.     

Trends in microbial control techniques for poultry products

Fresh poultry meat and poultry products are highly perishable foods and high potential sources of human infection due to the presence of several foodborne pathogens. Focusing on the microbial control of poultry products, the food industry generally implements numerous preventive measures based on the Hazard Analysis and Critical Control Points (HACCP) food safety management system certification together with technological steps, such as refrigeration coupled to modified atmosphere packaging that are able to control identified potential microbial hazards during food processing. However, in recent years, to meet the demand of consumers for minimally processed, high-quality, and additive-free foods, technologies are emerging associated with nonthermal microbial inactivation, such as high hydrostatic pressure, irradiation, and natural alternatives, such as biopreservation or the incorporation of natural preservatives in packaging materials. These technologies are discussed throughout this article, emphasizing their pros and cons regarding the control of poultry microbiota and their effects on poultry sensory properties. The discussion for each of the preservation techniques mentioned will be provided with as much detail as the data and studies provided in the literature for poultry meat and products allow. These new approaches, on their own, have proved to be effective against a wide range of microorganisms in poultry meat. However, since some of these emergent technologies still do not have full consumer's acceptability and, taking into consideration the hurdle technology concept for poultry processing, it is suggested that they will be used as combined treatments or, more frequently, in combination with modified atmosphere packaging.     

Food irradiation: is it an alternative to chemical preservatives?

Generalizations about effects of irradiation may be misleading if the dose and commodities are not specified. Irradiation could be used for inhibition of sprouting, disinfestation, destruction of parasites in meat, to delay maturation of fruit and for pasteurization and sterilization. In some applications it could replace chemical sprout inhibitors, fumigants and chemical preservatives; in other cases it may have unique advantages e.g. in eradication of non-spore-forming pathogens in dry or frozen foods. Toxicological and nutritional evaluation has repeatedly confirmed the safety of irradiated foods. Effects on nutritional quality are frequently comparable with heat treatment and sometimes more conservative, particularly if oxygen is excluded. While food irradiation could be an alternative to chemical preservatives, misinformation has led to uncertainties as to its future.     

Practical Food Safety Interventions for Dairy Production

Consumers are increasingly concerned about the safety of their food and uncertain about food production practices. Potential threats to human health related to dairy products and dairy farming include errors in pasteurization, consumption of raw milk products, contamination of milk products by emerging heat-resistant pathogens, emergence of antimicrobial resistance in zoonotic pathogens, chemical adulteration of milk, transmission of zoonotic pathogens to humans through animal contact, and foodborne disease related to cull dairy cows. Most dairy farmers feel responsible for the safety of milk and beef that originate on their farms, but linkage between farm production practices and the quality of processed products have been weak. The safety of dairy products can be enhanced by adoption of a number of management practices. Sources of microbial contamination of milk must be minimized by adoption of hygienic standards that can be easily evaluated. Uniform adoption of milking practices that reduce microbial contamination of milk should be emphasized. The diagnosis of salmonellosis or listeriosis on a dairy farm should be regarded as an indication that other potentially infected animals may be present in the herd. Coliform counts on bulk tank milk should be routinely performed as an indicator of fecal contamination. A reduction in the national regulatory limit for somatic cells in bulk tank milk should be considered based on potential enhancements in milk safety. Dairy farmers must take responsibility for the market cattle leaving their farms. The inappropriate or prophylactic use of antimicrobial agents must be minimized to ensure that antimicrobial resistance does not develop in animal pathogens. Consumers can have confidence in food safety programs on dairy farms that promote awareness and accountability for the products that are produced.