High-Pressure Processing of Milk and Dairy and Egg Products

Abstract

Nowadays, high-pressure processing (HPP) is commercially used for preservation of an increasing number of food products. High-pressure processing has demonstrated a positive effect on the quality of products compared with conventional thermal treatments. Pressures of between 300 and 600 MPa can cause inactivation of microorganisms, including foodborne pathogens, without damaging the nutritional and sensory characteristics of the products. There are other applications, such as some raw materials, that can be pressurized to keep or improve their functionality for food manufacture. The effect on the physical properties of foods can generate novel products. In each particular case, all advantages and disadvantages must be evaluated in advance. Combinations of HP with mild temperatures (30–50jC) and/or bacteriocins (nisin, pediocin, lacticin) sometimes improve the inhibition of foodborne bacteria and spores. Many studies have been performed on the application of high pressure to dairy products. The most important results may have a positive influence on the development of new products and on the increase of food safety of current products in the near future. When high pressure is applied to milk, the casein micelles disintegrate into casein particles of smaller diameter, with a decrease in milk turbidity and lightness and an increase in milk viscosity. In recent years, many studies have demonstrated the possibility of obtaining milk with a microbiological quality similar to pasteurized milk by applying 400–600 MPa. High pressure produces some modifications in size and distribution of milk fat globules. However, no damage to the milk fat globule membrane occurred. The effects of HPP on protein structure and mineral equilibrium may be very positive when applied during the processing of milk for cheese and yogurt production and the preparation of dairy products with novel textures. Pressures of 100–500 MPa improved the rennet coagulation properties of milk, although pressures above 300 MPa increase the rennet coagulation time of milk. Studies on fresh cheeses showed an increase in food safety because of the destruction of pathogenic and spoilage microorganisms when HPP was applied. The utility of HPP in cheese ripening is evident from the results obtained by different authors in some cheese varieties. However, further research is required to evaluate the full applicability of HP in accelerated ripening. Pressure could be used to