Zastosowanie wysokich ciśnień (HPP) do poprawy jakości mikrobiologicznej przetworów z mięsa drobiowego

Celem badań było określenie wpływu wysokich ciśnień na jakość mikrobiologiczną przetworów z mięsa drobiowego podczas ich przechowywania w warunkach chłodniczych. Próbki pasztetów, pieczeni oraz formowanych wyrobów z mięsa rozdrobnionego (kotletów) pakowano próżniowo, a następnie poddawano działaniu wysokich ciśnień (500 MPa, 10°C, 10 min). Grupę kontrolną stanowiły próbki przetworów, których nie poddawano HPP. Po określonym czasie przechowywania (1, 14 i 21 dób) przeprowadzano badania mikrobiologiczne, w których oznaczano: ogólną liczbę bakterii tlenowych mezofi lnych i psychrotrofowych, liczbę bakterii kwasu mlekowego, najbardziej prawdopodobną liczbę bakterii z grupy coli oraz obecność enterokoków. Wykazano, że zastosowanie wysokich ciśnień może być skutecznym sposobem na poprawę jakości mikrobiologicznej zapakowanych próżniowo przetworów z mięsa drobiowego. Dzięki tej metodzie można w znaczący sposób obniżyć liczbę bakterii mezofi lnych, psychrotrofowych oraz kwasu mlekowego, a przez to wydłużyć trwałość (przynajmniej do 14 dób) tego typu wyrobów, pod warunkiem przechowywania ich w temperaturze 4–6°C.

The aim of the study was to determine the effect of high pressure on the microbial quality of poultry meat products during storage under cooling conditions. The sampling material consisted of pâtés, roasts and formed products from minced meat (meat balls) which were manufactured on a laboratory scale accordingly to technology used in poultry industry. The heat treatment was conducted in an oven with convection (at a temperature of 180°C, to obtain 80°C in geometrical center). After cooling products samples weighing approx. 100 g were vacuum packed and then treated by high pressure (500 MPa, 10°C, 10 min). The control group consisted of product samples non-treated by HPP. The pressure process was conducted in a chamber with a volume of about 2000 cm3, which can be operated at a maximum pressure of 900 MPa at temperature ranging from –20 to +80°C. The mixture of water and propylene glycol (1 : 1) was used as a pressure transfer medium. After a certain time of storage (1, 14 and 21 days) the microbial tests were performed in which the total count of aerobic mesophilic and psychrotrophic bacteria, the count of lactic acid bacteria, the most probable count of coliform bacteria and presence of enterococci were determined. The experiment was carried out on three batches of poultry meat products, in two parallel repetitions. Based on the results, it was proven that application of high pressure (500 MPa, 10°C, 10 min) could be an effective method for extending the shelf life of vacuum-packed poultry meat products (at least up to 14 days), when stored at 4–6°C. Application of this method could signifi cantly reduce the count of mesophilic bacteria, psychrotrophic bacteria and lactic acid bacteria in this kind of products. Although, these bacteria are not covered by the requirements of the European Parliament and Council Regulation (EC) No 1441/2007 on the microbiological criteria for foodstuffs and do not pose a threat to public health security, however, could cause food spoilage. It has been shown that the degree of microbial inactivation as a result of high pressure depend on a large extent on the type of product and its initial microbiological contamination. Moreover, psychrotrophic bacteria and lactic acid bacteria were more sensitive to high pressure than mesophilic bacteria. In the analyzed poultry meat products, during the entire storage time, the presence of bacteria considered to be the main hygiene quality indicators i.e. coliform bacteria, which are sensitive to high temperature of processing and heat-resistant enterococci was not detected.