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This paper describes the new microbiological hazards in food. For protecting human health, nowadays food safety authorities face with many challenges, that years ago were largely unheard. In 2011 verocytotoxigenic Escherichia coli O104:H4 has been isolated in Germany. Strain came from fenugreek sprouts originated from Egypt. It was characterized by unique features such as presence of enteroaggregative Escherichia coli genes (aatA, aggR, aap, aggA, aggC) and resistance to most antibiotics. In Poland only three cases of disease caused by O104:H4 strain have been reported. Another emergence pathogen in Poland is Yersinia enterocolitica 08, biotype 1B. It is the most pathogenic bioserotype recently isolated in the USA only. Food-borne is commonly associated with raw or undercooked pork. The source of Yersinia spp. may be also milk and water. The presence ofbotulinum neurotoxins in food is not new, but still an important issue because of their high toxicity to human. Botulinum neurotoxins are high-molecular thermolabile proteins produced by Clostridium botulinum and some strains of Clostridium butyricum and Clostridium baratii. Based on their antigenic properties, botulin neurotoxins are divided into seven types A-G, however only types A, B, E and F are toxic to humans and some animals. Increasing risk associated with food results from antimicrobial resistance eg. extended spectrum beta-lactamases (ESBLs) producing bacteria, particularly Enterobacteriaceae. Until recently strains ESBL+ were isolated in hospitals, however during last years they have been isolated from healthy humans, animals and food of animal origin. Increasingly common microbiological hazard in food is methicillin-resistant Staphylococcus aureus (MRSA). Although prevalence of this pathogen in food is not high, the thread comes from difficulties of treating of infections caused by MRSA. The occurrence of food-borne in humans may also be associated with presence of viruses in food and water. The carrier of viruses may be equipment in food plant, production line, packaging and man. Most food-borne are caused by noroviruses, rotaviruses, hepatitis A virus and hepatitis E virus. An increased number of food-borne viral outbreaks are recorded in several countries. Reasons for this include the improved diagnostic methods that have enhanced detection of some virus groups, and the increased marketing of fresh and frozen foods that has led to a worldwide availability of high risk food. Viruses may contaminate food either through contamination at source, principally through sewage pollution of the environment, or in association with food

Fish and seafood are recommended diet constituents providing high quality protein, vitamins, minerals and omega-3 fatty acids, mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, these foodstuffs can also be the major source ofmethylmercury intake in humans. In general, more than 90% of the mercury in fish is found as methylmercury, but contents of methylmercury can vary considerably between species. Predatory species that are at the top of the food chain and live a long time, may accumulate higher levels of methylmercury. This paper contains information about sources of human exposure to organic compounds of mercury, toxicity, metabolism and transformation of mercury in the environment. Assessment of methylmercury by international risk assessment bodies such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and U.S. National Research Council (NRC) were presented. Climate changes and their influence on the mercury cycle in the environment especially mercury methylation and concentrations of methylmercury in marine species were also presented. Consumer advice prepared by European Commission and Member States as regards consumption of predatory fishes such as swordfish, tuna, shark, marlin and pike, taking into account the most vulnerable groups of population e.g. women planning pregnancy, pregnant or breastfeeding women and children were presented. Mercury and methylmercury contamination of fishes and seafood on the basis of the literature references as well as intake of mercury with fish and fish products in Poland and other European country were discussed. The role of selenium as a factor which counteracts methylmercury toxicity and protects against some neurological effects of methylmercury exposure in humans, as well as information on potential etiological factors connected with autism disorder were also described. Attention has also been drawn to increasing number of notifications to Rapid Alert System for Food and Feed (RASFF) concerning the contamination of fish and fish products with total mercury. European and national regulations concerning maximum permissible levels of mercury in food were also presented. Possibility of selection of different fish and seafood species, taking into account low methylmercury contamination and high contents of omega-3 fatty acids e.g. sardine, mackerel, anchovy, salmon, periwinkle, have been discussed.

Within the group of organochlorine, posing a positive danger the natural environment, the most interesting, controversial and objectionable for ecology++ are dioxins. In professional journals the name "dioxins" is a simplification which commonly refers to a certain group of organic chemical compounds, or, to be more precise, their derivatives called polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The latest research has confirmed the existence of yet another group of similar character polybrominated and polyfluorinated. Though other sources of industrial dioxins emission exist their first and foremost sources are incineration processes, in particular the processes of municipal, hospital and other toxic and chemical waste incineration. The compounds mentioned above, but all their isomers--tetrachlorodibenzodioxin (TCDD), tetrachlorodibenzofuran (TCDF)--are highly toxic and lack of emission control may prove highly hazardous for health and natural environment. The paper discusses a number of issues connected with dioxin emission during incineration of solid and gaseous municipal waste. A balance of the transport of dioxins between their source (i.e. the waste), through the process of their incineration and recombination, to the final stage--their presence in solid and gaseous incineration products. Following that European legislature on dioxin emission is discussed together with the presentation of state-of-the-art installations for reducing the amount of dioxins in exhausted gasses. Most of the research has been based on author's own observations and research done while taking active part in operation of selected waste incineration plants. The remaining data have been gathered from reference papers on current experiments carried out in European waste incineration plants. Summing up, the paper maintains that the incineration of municipal waste in state-of-the-art installations conforming to emission norms does not endanger the natural environment with dioxins emitted in exhaust gasses. This danger is, however, present in the solid incineration products due to high concentration of dioxins there. Operators are fully aware of this fact and attempt to counteract it. The awareness of presence of dioxins emitted in the process of waste incineration should be decisive factor while choosing technology and installation, which fitted appropriate cleanup equipment will guarantee level of dioxin emission safe for the environment and conforming to the norms of dioxin emission.