Future challenges to microbial food safety

Using nested PCR to detect the hlyA gene of Listeria monocytogenes in Minas Frescal cow's milk cheese

To evaluate a nested PCR protocol for Listeria monocytogenes detection, Minas Frescal cow's milk cheeses were produced, artificially inoculated with this pathogen at concentrations ranging from 1 to 1,000 CFU/g, and stored at 4°C for 10 days. The International Organization for Standardization (ISO) standardized method 11290-1/A1 was used to detect L. monocytogenes in the inoculated samples, and DNA was extracted from aliquots (1, 5, and 10 ml) of 1:10 dilution, followed by a nested PCR protocol for the hlyA gene. The ISO standardized reference method and nested PCR both detected L. monocytogenes at all concentrations and during all storage periods; McNemar's test showed no significant difference (P > 0.05). The results indicated that the nested PCR protocol can be used as a screening test to detect L. monocytogenes in Minas Frescal cheese, allowing earlier detection of the pathogen that can later be confirmed by the ISO standardized reference method.

Enteric protozoa in the developed world: a public health perspective

Several enteric protozoa cause severe morbidity and mortality in both humans and animals worldwide. In developed settings, enteric protozoa are often ignored as a cause of diarrheal illness due to better hygiene conditions, and as such, very little effort is used toward laboratory diagnosis. Although these protozoa contribute to the high burden of infectious diseases, estimates of their true prevalence are sometimes affected by the lack of sensitive diagnostic techniques to detect them in clinical and environmental specimens. Despite recent advances in the epidemiology, molecular biology, and treatment of protozoan illnesses, gaps in knowledge still exist, requiring further research. There is evidence that climate-related changes will contribute to their burden due to displacement of ecosystems and human and animal populations, increases in atmospheric temperature, flooding and other environmental conditions suitable for transmission, and the need for the reuse of alternative water sources to meet growing population needs. This review discusses the common enteric protozoa from a public health perspective, highlighting their epidemiology, modes of transmission, prevention, and control. It also discusses the potential impact of climate changes on their epidemiology and the issues surrounding waterborne transmission and suggests a multidisciplinary approach to their prevention and control.

The formation of Staphylococcus aureus enterotoxin in food environments and advances in risk assessment

The recent finding that the formation of staphylococcal enterotoxins in food is very different from that in cultures of pure Staphylococcus aureus sheds new light on, and brings into question, traditional microbial risk assessment methods based on planktonic liquid cultures. In fact, most bacteria in food appear to be associated with surfaces or tissues in various ways, and interaction with other bacteria through molecular signaling is prevalent. Nowadays it is well established that there are significant differences in the behavior of bacteria in the planktonic state and immobilized bacteria found in multicellular communities. Thus, in order to improve the production of high-quality, microbiologically safe food for human consumption, in situ data on enterotoxin formation in food environments are required to complement existing knowledge on the growth and survivability of S. aureus. This review focuses on enterotoxigenic S. aureus and describes recent findings related to enterotoxin formation in food environments, and ways in which risk assessment can take into account virulence behavior. An improved understanding of how environmental factors affect the expression of enterotoxins in foods will enable us to formulate new strategies for improved food safety.

Emerging Risks Related to Food Technology

Global food security and safety are threatened by a number of fast-occurring changes, even in the absence of natural disasters or terrorist attacks: overpopulation and urbanisation, environmental pollution, climate changes, intensive animal breeding, international trade and travel, emerging water- and food-borne diseases, antimicrobial-resistant bacteria, increasing food costs, complexity of food supply chains, malnutrition and risky food behaviour. Food safety management tools, including food legislation, national and international standards, quality management systems, risk analysis, risk-based inspections and controls, monitoring and alert systems for food contaminants and food-borne diseases, quantitative microbial risk assessment, nutrition and toxicology studies, and elaborate food processing technologies have brought to consumers in developed countries a wide selection of safe foods. Predictive and early warning and communication systems are being developed to increase the ability to “expect the unexpected” and take prevention measures before food hazards become real risks. The production, processing, transportation, storage and/or distribution stages of modern food supply chains remain exposed to various types of biological or chemical contaminants, as evidenced by recent events or crises. The prion/BSE, dioxin, acrylamide, melamine, bisphenol A cases, and the numerous pathogen outbreaks illustrate this exposure. The melamine story and the international traffic of counterfeited foods and drinks show that profit-motivated fraud and adulteration are rising threats, opening potential paths for terrorist actions. Recent food preservation, processing or packaging technologies and trends, in spite or because of their benefits (mild treatment, extended product shelf-life, “fresher” quality, RTE pre-cooked convenience) also bring safety risks at the consumer level: incomplete microbial inactivation, possible non respect of adequate storage conditions and expiration dates, undercooking, and generation of stress-resistant micro-organisms. Innovative technologies, such as the use of nanoparticules in foods or food contact materials, and the development of active, intelligent or sustainable food packaging entail uncertainties and safety concerns. Natural disasters, droughts, floods, conflicts, and poverty often lead to emergency situations requiring large assistance operations with complex logistics and specific meals ready-to-eat or nutrient-supplemented foods. Containerised food processing units that could be deployed and quickly set to operate in ­production-disrupted areas are being developed by the World Food Programme. Other strategies against food insecurity include insurance policies for crop failures and renting of agricultural lands abroad. Citizen perception of food safety risks and the EU consumers’ “right to informed choice” explain why some technologies elicit rejection: ionising irradiation of foods, hormonal and antibiotic treatment of animals, the use of various “­artificial” food additives, genetically modified crops and ingredients, cloned animals. Perceived benefits responding to consumers’ needs (healthier, more nutritive, higher quality, more convenient, lower cost), “naturalness”, respect of the environment and trusted information are the major factors influencing consumers’ acceptance of innovative food technologies and products. Novel foods and technologies are also subject to strict regulatory pre-market safety assessment and authorisation procedures. While necessary for protection against unexpected risks, some of these rules serve as barriers to innovation and trade, and fodder for strong political debates.

Development and implementation of a system for the early identification of emerging risks in food and feed

According to EFSA's Founding Regulation, the Authority is required to "undertake action to identify and characterise emerging risks" in the field of food and feed safety. EFSA provides scientific advice to the risk manager, at both European and Member State level, for the identification of risks present in the food chain. In the area of currently unrecognised but potentially significant risks for public health, EFSA has set up a dedicated unit on emerging risks (EMRISK). Through the identification of drivers of emerging risks, EFSA also intends to anticipate future risks derived from changes in current food/feed production practices or factors impinging on food/feed production or changes in human exposure through food consumption. EFSA aims to establish a data monitoring capacity, data filtering methodology and networking structures to identify emerging risks and drivers of emerging risks in a timely fashion and to communicate these to the risk manager. To date, the first step of this process (data monitoring) is in place. The following steps, that is, filtering and communication, are being rapidly established. Whilst the current data sources monitored are limited, they have been sufficient to enable the elaboration of the procedures for the next steps in the emerging risks identification process. As more data sources become accessible, the process will become more effective. All processes should be in place by mid -2010 and reported on in EFSA's first annual report on emerging risks in 2011. By the end of the second year of operation (2012), the soundness and utility of this approach will be given an initial review.

Trends in technology, trade and consumption likely to impact on microbial food safety

Current and potential future trends in technology, consumption and trade of food that may impact on food-borne disease are analysed and the key driving factors identified focusing on the European Union and, to a lesser extent, accounting for the United States and global issues. Understanding of factors is developed using system-based methods and their impact is discussed in relation to current events and predictions of future trends. These factors come from a wide range of spheres relevant to food and include political, economic, social, technological, regulatory and environmental drivers. The degree of certainty in assessing the impact of important driving factors is considered in relation to food-borne disease. The most important factors driving an increase in the burden of food-borne disease in the next few decades were found to be the anticipated doubling of the global demand for food and of the international trade in food next to a significantly increased consumption of certain high-value food commodities such as meat and poultry and fresh produce. A less important factor potentially increasing the food-borne disease burden would be the increased demand for convenience foods. Factors that may contribute to a reduction in the food-borne disease burden were identified as the ability of governments around the world to take effective regulatory measures as well as the development and use of new food safety technologies and detection methods. The most important factor in reducing the burden of food-borne disease was identified as our ability to first detect and investigate a food safety issue and then to develop effective control measures. Given the global scale of impact on food safety that current and potentially future trends have, either by potentially increasing or decreasing the food-borne disease burden, it is concluded that a key role is fulfilled by intergovernmental organisations and by international standard setting bodies in coordinating the establishment and rolling-out of effective measures that, on balance, help ensure long-term consumer protection and fair international trade.