Improvement of microbiological safety and shelf-life of pulse spreads through sous vide and high pressure processing

A. Kirse*, R. Galoburda, S. Muizniece-Brasava, D. Karklina and L. Skudra

Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, 22 Rigas Street, LV3004, Jelgava, Latvia
*Correspondence: asnate.kirse@llu.lv

Abstract:

Microbiological quality of sous vide treated (80 °C/15 min) and high pressure processed (700 MPa/10 min/20 C) cowpea (Vigna unguiculata (L.) Walp. cv. Fradel) and maple pea (Pisum sativum var. arvense L. cv. Bruno) spreads in flexible vacuum packaging during 62-day storage at 5 ± 1 °C were assessed. Pulse spreads, made from cooked pulses with salt, citric acid, oil, and seasoning, were filled in PA/PE or PET/ALU/PA/PP flexible film pouches, packaged in vacuum (20 mbar) and hermetically sealed. Microbiological testing was performed by determining total plate count, yeast and mould count on days 0, 15, 29, 42, 50, 57, and 62, and the presence of B. cereus, C. perfringens and E. coli before processing and after 62-day storage. The results showed that total plate count increased significantly after 62-day storage in both sous vide (P = 0.011) and high pressure processed (P = 0.017) spreads; the observed over one-log increase was without significant differences between pulse spreads and packaging materials (P < 0.05). The admissible level of total plate count (Nmax < 3.69 log CFU g-1) in pulse spreads was not exceeded. The presence of yeasts and moulds, C. perfringens and E. coli in pulse spreads was not confirmed, whereas B. cereus accounted to <102 CFU g-1 after 62-day storage. The suggested shelf-life of processed pulse spreads is 62 days; except for sous vide treated spreads with seasoning in both packaging materials- 57 days. Both processing methods are suitable to ensure the production of high quality pulse spreads with adequately long shelf-life.

Key words:

The hygienic and nutritional quality of milk from Saanen goats bred in the Moravian-Silesian region

T. Michlová¹*, H. Dragounová², R. Seydlová² and A. Hejtmánková¹

¹Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, CZ165 21, Prague, Czech Republic
²Dairy Research Institute Ltd, Ke dvoru 791/12A, CZ160 00, Prague, Czech Republic
*Correspondence: michlova@af.czu.cz

Abstract:

The aim of the study was to monitor milk yield and the hygienic and nutritional quality of milk of Saanen goats in the Moravian-Silesian region in Czech Republic. Milk samples were collected once a month during the lactation period. The average milk yield in the standardized lactation was 1,100 liters. The somatic cell count in pool samples ranged from 470 x 103 to 696 x 103. The total microorganism count ranged from 3.6 x 103 to 1.4 x 105. The pathogen Staphylococcus aureus was proven no more than in 6.3%. The highest values of all main components of milk were achieved within a relatively short time after kidding (April 2015). The average content of fat was 3.64  0.52 g 100 ml^-1, 3.17  0.16 g 100 ml^-1of protein, 2.60  0.06 g 100 ml^-1 of casein, 4.56  0.24 g 100 ml^-1 of lactose, and 12.02  0.80 g 100 ml^-1 of solids. Average content of vitamin A was 0.27  0.14 mg kg^-1 and average content of vitamin E was 0.60  0.34 mg kg^-1. Content of vitamin E increased almost continuously during the lactation, and the content of vitamin A was significantly higher at the end of lactation. In lyophilized milk powder the average trace metal contents were 7.76  0.92 g kg^-1 Ca, 1.62  0.26 g kg^-1 Mg, 15.3  1.43 g kg^-1 K, 789  111 mg kg^-1 Na, 23.2  2.73 mg kg^-1 Zn, and 0.85  0.55 mg kg^-1 Cu. Contents of minerals varied during the lactation period, but no significant trends were observed.

Key words:

Ca, casein, Cu, fat, K, lactose, Mg, Na, pathogens, protein, somatic cell count, total microorganism count, vitamin A, vitamin E., Zn