The purpose of this study was to optimize the kefir grains biomass production, using milk as culture media. The kefir grains were cultured at different changed conditions (temperature, time, shaker rotating speed, culture media supplemented) to evaluate their effects. Results showed that optimal culture conditions were using the organic skim milk, incubated at 25°C for 24 hours with a rotation rate of 125 rpm. According to results, the growth rate was 38.9 g/L for 24 h, at 25°C using the organic milk -OSM, 36.87 g/L during 24 hours, optimal time for propagation process gave 37.93 g/L kefir grains biomass when the effect of temperature level was tested. The homogenization of medium with shaker rotating induced a greater growth rate, it was obtained 38.9 g/L for 24 h, at 25°C using rotation rate at 125 rpm. The growing medium (conventional milk) supplemented with different minerals and vitamins may lead to improve the growth conditions of kefir grains biomass. The optimization of the growth environment is very important for achieving the maximum production of kefir grains biomass, substrate necessary to obtain the polysaccharide kefiran.

The raw material (pork sirloin) used for manufacturing smoked sausages was purchased from a local butchery (Cluj-Napoca, Romania). Brewer's spent grain, the by-product generated

The probiotic properties and the viability of lactic acid bacteria of fermented dairy products can be improved by addition of bioactive compounds originating from natural sources (e.g. goji berries). This study aimed to evaluate how goji berries and honey affect the sensorial quality of yoghurt, the chemical properties, the viability of lactic acid bacteria (LAB) and the concurrent microflora development. Two types of yoghurts (yoghurt with goji berries and yoghurt with honey and goji berries) were developed. The addition of honey affected the entire yoghurt microflora including LAB, manifesting bactericidal effect. The addition of goji berries maintained the viability of LAB at probiotic levels (10 6 -10 7 log CFU/ml) during 21 days of storage; compared to classic yoghurt, LAB viability decreased during storage at 10 3 log CFU/ml. Goji berries also improved sensory acceptance of consumers. The results obtained in this study collect information that enables the use of goji berries as enhancer of probiotic levels in yoghurt, while honey can provide bacteriostatic/bactericidal effect for contaminants.

Past research on the association of natural antimicrobials and low temperatures for fruit juices pasteurization has not targeted acid-adapted strains which are yet the most relevant strains in these products. We found that previously acid-adapted Escherichia coli ATCC 25922 cells exhibited an increase of their resistance to thermal inactivation at 55 8C for 5 min both in the presence and absence of carvacrol (30 mL/L). The inactivation of E. coli was more intense in pineapple (pH 3.25) and orange (pH 3.61) juice, than in watermelon juice (pH 5.4). Supplementation of juices with carvacrol decreased the survival of both acid-adapted and non-adapted bacterial cells. Our results suggest that the supplementation of fruit juices with natural antimicrobials, such as carvacrol, may contribute to counteract the mild thermal tolerance developed by acid-adapted bacteria. Given the different properties of fruit juices, such combined treatments need to be developed specifically for each fruit product. Practical applicationsSupplementation of fruit juices with natural antimicrobials has been described to increase the efficiency of microbial mild thermal inactivation treatments. However, its effect on the thermal resistance of acid-adapted cells has not previously been addressed. We observed that acid adaptation enhances mild thermal tolerance. Our results suggest that natural antimicrobials can effectively counteract the mild thermal tolerance of acid-adapted cells. The combination of mild temperature treatments and natural antimicrobials is a firm alternative to conventional pasteurization to ensure the safety of fruit juices without affecting their nutritional properties. Moreover, this combined strategy does not require expensive novel technologies or high energy consumption.

Four essential oils isolated from dried leaves of parsley, lovage, basil and thyme were investigated by FTIR spectroscopy. The analysis of recorded spectra revealed that the main compounds of tested essential oils dominate their vibrational spectra.