Characterization of anti-listerial bacteriocin produced by lactic acid bacteria isolated from traditional fermented foods from Cambodia

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Influence of the use of milk replacers and pH on the texture profiles of raw and cooked meat of suckling kids

The aim of this work was to study the texture profile of fresh and cooked longissimus thoracis et lumborum muscle from suckling kids raised with natural milk or milk replacers. Suckling Male kids from eight goat breeds (Florida, FL; Cabra del Guadarrama, GU; Majorera, MA; Palmera, PL; Payoya, PY; Retinta, RE; Tinerfeña, TI; Verata, VE), all of single parturition, were raised with milk replacers (MR) or with natural milk from the dams (NM). The meat pH, Warner-Bratzler shear force, texture profile analysis and chemical composition were determined. Kids were clustered based on their pH by k-means clustering. The effect of the rearing system on the textural profile was strongly modulated by breed. The values of Warner-Bratzler shear force and hardness found in these breeds under both rearing systems were very low. Hence, the toughness of very light suckling kids should not be a determining factor in choosing a breed or rearing system. Nevertheless, the use of milk replacers increased the presence of meat with high pH, which modified the textural parameters, decreasing the shear force but increasing cohesiveness and adhesiveness. Consequently, depending on the commercial strategy of the farm, the election of the breed and rearing system must be considered together

Effect of protective cultures and different modified atmosphere packaging on Listeria innocua growth and on sensory properties in sliced cured-smoked pork loin

This study aims to evaluate the antimicrobial effect of two protective cultures combined with different modified atmosphere packaging (MAP) systems on Listeria innocua growth in sliced ready-to-eat pork loin, a Portuguese traditional cured-smoked product (Lombo). Two protective lactic acid (LAB) cultures - Lactobacillus sakei ST153 and BLC35 (CHR Hansen) were tested for their ability against L. innocua 20130c growth (as a surrogate for L. monocytogenes) in sliced “lombo” packed in two MAP conditions, (20%CO2/80%N2 and 40%CO2/60%N2) and stored at 5oC. The influence of MAP and protective cultures in the sensory characteristics of the product was also evaluated by semi-trained panel of fifteen judges. The MAP affected the growth of L. innocua, the Listeria population decreasing 3 log CFU/g after 120 days of storage at 5oC. In samples containing protective cultures a reduction of 1–2 log CFU/g in counts of L. innocua was observed after 12 hours. At the end of storage results indicated that L. sakei ST 153 was more efficient than BLC35 culture on inhibiting L. innocua growth and this inhibition was enhanced by MA (40%CO2/60%N2). Results of sensory evaluation showed that oiliness, hardness, succulence, and characteristic taste attributes of “lombo” decreased during storage whereas the bitter taste increased in both LAB applications and no significant differences between LAB cultures or MAP conditions were found

Enhancement of bacteriocin production and antimicrobial activity of Pediococcus acidilactici HA-6111-2

The effect of sequential treatments of pressure (50–150 MPa, 10 ºC, 5 min) and temperature (57 ºC, 15 min) on the survival and bacteriocin production of Pediococcus acidilactici HA-6111-2 cells in the exponential growth phase was assessed. The growth curves were fitted with the modified Gompertz model, and the estimated maximum specific growth rate was considered to be pressure dependent. A delay in the maximum value of bacteriocin production was registered for more severe pressure conditions, but it was found more notorious for pressure followed by temperature treatments. At lower pressure intensity treatment, regardless of the application order, there was an enhancement of bacteriocin production per cell when compared to the control while maintaining the maximum production value. Bacteriocin production after the treatments can be described by an exponential model

Effect of high pressure on growth and bacteriocin production of Pediococcus acidilactici HA-6111-2

This study was aimed to investigate the effect of high pressure processing (HPP, 200-600MPa) on the (i) survival of Listeria innocua and Pediococcus acidilactici HA-6111-2; (ii) production of bacteriocin bacHA-6111-2 and (iii) activity of bacteriocin against untreated and pressure-treated L. innocua cells. Inactivation of P. acidilactici was observed for pressures of >300MPa. However, at this pressure level, L. innocua was more sensitive. Bacteriocin crude extract was pressure stable, with a decrease for pressures of 400 MPa. Pressures of 200MPa did not affect bacteriocin production when compared with non-pressure-treated cells, whereas higher pressures caused a 2- to 4-fold decrease on the maximum level of bacteriocin production. Growth curves of P. acidilactici were fitted with the modified Gompertz model. The lag phase period depended on the magnitude of the pressure applied: there was a delay in the exponential phase as pressure increased and, as a consequence, in the beginning of bacteriocin production. Since P. acidilactici HA-6111-2 and its bacteriocin have shown resistance to pressures up to 300-400 MPa, they could be used in combination with HPP in order to improve food safety.info:eu-repo/semantics/publishedVersio

Persistent and non-persistent strains of Listeria monocytogenes: A focus on growth kinetics under different temperature, salt, and pH conditions and their sensitivity to sanitizers

This study aimed to investigate the effect of different conditions, including temperature (37 C, 22 C, and 4 C), NaCl concentrations (2.5%, 4%, and 8%), and acidity (pH ¼ 5), on the growth response of persistent and non-persistent isolates of Listeria monocytogenes. The resistance to two common sanitizers (benzalkonium chloride and hydrogen peroxide) was also investigated. A selected group of 41 persistent and non-persistent L. monocytogenes isolates recovered from three cheese processing plants during a previous longitudinal study was assembled. Average lag time was similar for persistent and non-persistent isolates grown at 37 C, 22 C and 4 C but significantly shorter (p < 0.05) for persistent isolates grown at 2.5%, 4% and 8% NaCl, and at pH 5. Average growth rates were significantly higher (p < 0.05) for persistent than for non-persistent isolates when grown at 22C, 2.5%, 4% and 8% NaCl, and at pH 5. These results suggest that persistent strains may be better adapted to grow under stressful conditions frequently encountered in food processing environments than non-persistent strains. No relation between persistence and resistance to the tested sanitizers was found.info:eu-repo/semantics/publishedVersio

Biopreservation strategies in combination with mild high pressure treatments in traditional Portuguese ready-to-eat meat sausage

Thrombomodulin (TM) is an endothelial cell membrane protein that acts as a major cofactor in the protein C anticoagulant pathway. The EGF-like domains 4-6 of TM (TM456) are essential for PC activation. In this study, we proposed a liposomal recombinant TM conjugate to mimic the membrane TM structure and its anticoagulant activity. First, a DSPE-PEG2000-TM456 was successfully synthesized by site-specific conjugation of azido-TM456 with DSPE-PEG2000-DBCO via copper-free click chemistry quantitatively. Then, liposome-TM456 was fabricated via direct liposome formation with the DSPE-PEG2000-TM456 and other lipids. This liposomal formulation of TM456 retained protein C activation activity as that of TM456. Also, liposome-TM456 was much more stable and had a longer plasma half-life than TM456 and DSPE-PEG2000-TM456, respectively. Moreover, liposome-TM456 showed in vivo anticoagulant effect by decreasing the mortality from 80% to 20% in a thrombin-induced thromboembolism mouse model. The reported liposome-TM456 conjugate mimics the endothelial TM anticoagulation activity and may serve as an effective anticoagulant agent candidate for future development.info:eu-repo/semantics/publishedVersio