High pressure processing (HPP) is a cold pasteurisation method, in which the products are generally processed at 300–800 MPa for a few minutes. Processing generally happens below 45 °C, so the treatment preserves the nutritional and sensory properties of the products. The literature review discussed high pressure processing as a food processing method and studied its effects on food. The focus was on the effects on microbes, enzymes, structure and chemical properties of dairy and vegetable products. The aim of the experimental research was to study the effects of high pressure processing on the microbiological and sensorial shelf life of blueberry puree, raw milk and roasted cheese. The objective was also to examine the shelf life of the products that can be achieved when using high pressure processing. Blueberry puree was analyzed for microbiological quality, pH, color and sensory properties during storage of 2 months. Raw milk and roasted cheese was analyzed for microbiological and sensory quality. Roasted cheese was also analyzed for total solids content. The raw milk was stored for 1 month and the roasted cheese for 3 months. The microbiological quality of high pressure processed raw milk remained good about two weeks. The sensory quality remained good for about 9 days. After three weeks, the high pressure processed raw milk reached the same microbiological level than reference sample on day 1. No difference occurred in color and pH between the high pressure processed blueberry puree samples and the reference samples during the storage. High pressure processed blueberry puree remained microbiologically high quality 8 weeks, while the reference puree was good only for 2 weeks. All blueberry purees remained sensorically good for 8 weeks. The shelf life of the roasted cheese after high pressure processing was approximately 1 month: reference samples remained good for 2 weeks. Mini roasted cheese remained microbiologically good for up to 3 months while the sensory quality declined after 2 months. High pressure processing significantly increases the microbiological shelf life of the product. Enterobacteriaceae, yeasts and molds are effectively inactivated by high pressure processing. Pseudomonas bacteria, which can produce pressure resistant enzymes like lipases, are more resistant to high pressure.