Milk is a food of high nutritional value processed by heat treatment. Heat treatment of milk is a technological process designed to inhibit the growth of microorganisms and extend the shelf life of products. The heating process directly affects the molecular structure of whey proteins by the process of denaturation. It leads to the formation of a whey protein–casein polymer complex. Based on these facts, milk heat-treatment conditions should be controlled during milk processing. This work focuses on describing the whey protein denaturation process and formation of the complex of whey protein with casein. The effect of heat treatment on individual milk protein fractions alpha-casein (α-cas), beta-casein (β-cas), kappa-casein (κ-cas), beta-lactoglobulin (β-lg) and alpha-lactalbumin (α-la) was studied by SDS-PAGE. Formation of the whey protein–casein polymer complex increased significantly (p < 0.05) on increasing the temperature and duration of the heat treatment.

Eating food is one of the most important needs of every person, so their safety and quality should be crucial for everyone. People expect, that food they eat is hygienically and health safe. Unfortunately, people usually start to focus on food safety only when various food scandals are exposed and it is too late. Mass consumption of food is the cause of a high risk to human health, but only in the case of harmful food. Food-borne diseases are a common and widespread phenomenon in all parts of the world, regardless of the economic development of the country. Protection of human, animal and plant health is one of the main economic priorities of each country. The political objective of the European Union is therefore to ensure that European Union citizens have access to safe and nutritious foods, so it must meet strict safety standards. In ensuring food safety, it is necessary to take into account all aspects of the food production chain as a whole, because each subject can have a potential impact on food safety. This paper deals with the issues of food safety and food quality. The main objective was to find out how consumers perceive higher quality food and whether they read information included on the food packaging. Primary data were obtained from a survey that was conducted on the sample of 478 respondents living in Slovakia. For a deeper analysis, several assumptions, which were verified by Friedman Test, Chi-Square Test of Independence, Wilcoxon Signed-Rank Test, were formulated. The survey has found out that 84% of respondents buy higher quality food and 60% purchase them because of health-related reasons. More than half of respondents search for the information about food safety on the Internet and the same percentage considere government as the most reliable source of information about food safety. Unfortunately, just more than one quarter of them read the information on food label and for 34% is this information unsufficient.

Food industry along with agriculture constitute a major economy sector in most countries, because in addition to water intake and oxygen availability, food is another basic determinant for functioning of the human organism. For the proper functioning of human body, it is imperative that the customer chooses food so that the daily diet includes all the necessary nutrients in a reasonable proportion. At present, however, it is becoming more and more common that foodstuffs do not meet strict standards, are not properly stored, the packaging is damaged, or hygiene standards are not being adhered to, and therefore, in addition to health benefiting substances, they also contain harmful ones. According to the World Health Organization, the death of up to 2 million people a year around the world is caused by foods harmful to human health. The main objective of this report was to assess how consumers perceive the health safety of food in Slovakia and to find out whether some types of food are considered as potentially harmful to health. Primary data were obtained through a questionnaire survey conducted from October to December 2017 on a sample of 478 respondents. Respondents answered to 12 factual, and 9 classification questions, which were consequently analyzed using the Friedman test, Nemenyi test and Chi-Square test of Independence. Survey results showed that the majority of respondents had concerns about the health harming effects of food only occasionally and they trust the hygienic level of the restaurant facilities (60.5%), fast food (53%) and frozen food (49.2%) with few reservations. As the most hazardous foods are considered poultry meat, eggs and mayonnaise. If the consumer's health is endangered by food, the guilty party should be punished by ban (61.9%) or by suspension (19.5%).

Microplastic food contamination has become a growing concern due to its potential impacts on human health. Microplastics are tiny plastic particles less than 5mm in size that can originate from various sources, such as cosmetics, textiles, and plastic packaging. These particles can enter the food chain through multiple routes, such as the environment, food processing, and packaging. They can accumulate in different types of food, including seafood, drinking water, and agricultural produce. Exposure to microplastics through food consumption is a significant concern, as it is difficult to avoid and can potentially cause adverse health effects. Microplastics can accumulate in the human body and have been linked to various health issues, such as inflammation, organ damage, and the disruption of endocrine and immune systems. Additionally, microplastics can act as vectors for harmful chemicals and pathogens, further exacerbating their potential health impacts. Several studies have documented the presence of microplastics in different food products, with varying concentrations depending on the type of food and its origin. Due to their filter-feeding behaviour, contamination levels are exceptionally high in seafood, such as fish and shellfish. Additionally, studies have found microplastics in bottled and tap water, beer, honey, salt, and even air. Efforts to mitigate microplastic contamination of food include developing better waste management practices, promoting biodegradable and compostable packaging, and improving food processing methods. However, much more research is needed to fully understand the extent of microplastic contamination in food and its potential impacts on human health. Microplastic contamination of food is a complex issue requiring a multidisciplinary approach to address its ecological and human health implications fully. By raising awareness and promoting sustainable practices, we can work towards reducing our exposure to microplastics in food and protecting public health.

Milk testing and quality control should be carried out at all stages of the dairy chain. Milk can be tested for quantity, organoleptic characteristic, compositional characteristic, physical and chemical characteristics, hygienic characteristics, adulteration or drug residues. The content of the major constituents of raw milk is important for milk payment system. Enzymes naturally present in the milk can change the chemical composition of raw milk. Also, enzymes secreted by bacteria or enzymes from somatic cells can degrade the raw milk composition. Products of these degradation reactions can have undesirable effects on milk structure, smell and taste. It is very important that farm-fresh raw milk be cooled immediately to not more than 8 °C in the case of daily collection, or not more than 6 °C if collection is not daily. During transport the cold chain must be maintained. An authorized person, properly trained in the appropriate technique, shall perform sampling of bulk milk in farm. Laboratory samples should be dispatched immediately after sampling to the dairy company and consequently to the testing laboratory. The time for dispatch of the samples to the testing laboratory should be as short as possible, preferably within 24 h. Laboratory samples shall be transported and stored at temperature 1 to 5 °C. Higher temperatures may adversely affect the composition of the laboratory sample and may cause disputes between the farmer, the dairy company and the laboratory. The effect of refrigerated storage at temperature 4 °C during 24 h on the composition of raw milk were investigated in this work, because we wanted to know how the milk composition will be changed and how the laboratory results will be affected. In many cases, the samples are not preserved with chemical preservants like azidiol, bronopol, potassium dichromate or Microtabs. We found, that the composition of raw cows' milk after 24 was changed significantly (p >0.005). We found an average decrease in the fat content of -0.04 g/100g, increase in the protein content of +0.02 g/100g, increase in the lactose content of +0.02 g/100g, increase in the solid-not-fat content of +0.02 g/100g and decrease in the total solid content of -0.02 g/100g. It is necessary to cool the raw cows' milk after the milking to decrease the changes in milk composition caused mainly due to the lipolytic activity of lipase