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Essential oils (EOs) represent a pivotal source for developing potent antimicrobial drugs. However, EOs have seldom found their way to the pharmaceutical market due to their instability and low bioavailability. Nanoencapsulation is an auspicious strategy that may circumvent these limitations. In the current study, lemongrass essential oil (LGO) was encapsulated in zein-sodium caseinate nanoparticles (Z-NaCAS NPs). The fabricated nanocomposite was characterized using dynamic light scattering, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and transmission electron microscopy. The antimicrobial activity of LGO loaded NPs was assessed in comparison to free LGO against Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, and Klebsiella pneumoniae. Furthermore, their antibacterial mechanism was examined by alkaline phosphatase, lactate dehydrogenase, bacterial DNA and protein assays, and scanning electron microscopy. Results confirmed the successful encapsulation of LGO with particle size of 243 nm, zeta potential of – 32 mV, and encapsulation efficiency of 84.7%. Additionally, the encapsulated LGO showed an enhanced thermal stability and a sustained release pattern. Furthermore, LGO loaded NPs exhibited substantial antibacterial activity, with a significant 2 to 4 fold increase in cell wall permeability and intracellular enzymes leakage versus free LGO. Accordingly, nanoencapsulation in Z-NaCAS NPs improved LGO physicochemical and antimicrobial properties, expanding their scope of pharmaceutical applications. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) play many function roles during the preparation food; one of those roles is to remove or reduce mycotoxins from contaminated food. Therefore, this study aimed to study the impact of five strains from LAB (Lactobacillus rhamnosus, Lactobacillus plantarum, Bifidobacterium bifidum, Streptococcus thermophilus and Lactobacillus reuteri) to reduce aflatoxin B1 (AFB1) during manufacturing Fino bread. Also, this study has been extended to evaluate the qualities and characteristics of the Fino bread manufactured by treated wheat flour by LAB cells. The data reflected that the percentages of reduction of AFB1 after mixing ingredients were 9.7, 8.5, 7.04, 7.4 and 5.5% with addition L. rhamnosus, L. plantarum, Bifidobacterium bifidum, Str. Thermophilus and L. reuteri, respectively. Moreover, the results indicated that the addition of L. rhamnosus and L. plantarum cells given the highest percentage of removal AFB1 after fermentation stage were 60.5 and 54.25%, respectively, while the lowest reduction of AFB1 recorded with the addition of L. reuteri cells was 42.25%. AFB1 reduction has reached 100% in blends treated with L. rhamnosus and L.plantarum cells in the final bread. The results indicated that the increase in water absorption and the dough development time as well as dough weakening. Finally, the addition of LAB cells didn't show any significant differences in taste, color, odor, and texture for the final bread. [ABSTRACT FROM AUTHOR]

Aflatoxin B1 (AFB1) and ochratoxin A (OTA) are two of the most important of mycotoxins associated with tropical and subtropical climate as in Egypt. Therefore, this study aimed to isolated lactic acid bacteria (LAB) and Bifidobacteria from some local dairy products from Egypt and using some strains to reduce/or remove AFB1 and OTA toxins. Fifty samples, of milk and dairy products, including ten samples each, of Kareish, Damietta cheese (soft type), buffalo's milk, yoghurt (zabady), and naturally acidified milk (Rayeb)were screened for their load of Lactobacilli, Lactococci and Bifidobacteria, using MRS agar, M17 agar and (MRS-Cys) agar, respectively. The obtained data indicated that 38, 31 and 22 isolates belonged to Lactobacillus, Lactococcus and genus Bifidobacterium, respectively. Fourteen strains isolated from LAB and Bifidobacterium were tested on AFB1 and OTA in PBs contaminated by10 ppb with three times incubation periods (6, 12 and 36 hours) at 37°C. The results indicated that all tested strains were able to reduce AFB1 at different rates ranging between 12.1 to 65.4% after incubation for 6 h. These rates increased to 78.8% and 89.9% after incubation at 37°C for 12 and 36h, respectively. The same results were with OTA, where percentages of reduction ranging from 81.4 to 80.4% were obtained when incubation with LAB cells was done at 37°C and prolonged to 36 h. According to the results, the percentage of reduction increased with the increasing time for each strain. [ABSTRACT FROM AUTHOR]

Street-vended ready-to-eat food sold in Egypt, including sandwiches and dishes of traditional food, was examined for the presence of Listeria species. Out of 576 samples, 24% were found to contain Listeria species. L. monocytogenes and L. innocua were isolated from 57% and 39% of the contaminated samples, respectively. Other Listeria spp. were detected with lower frequency. L. monocytogenes of Ζ103 CFU/g were detected in 7% of the total examined samples, which represent 49% of the contaminated food samples (meat, poultry, seafood, dairy products, and products of plant origin). Most of the samples contaminated by L. monocytogenes had high levels of total viable bacterial counts. The results obtainedmay help to clarify the epidemiology of listeriosis in the country and draw the attention of the decision makers to issue hygienic regulations for food processing industries as well as street vendors in order to ensure safe street-vended ready-to-eat food. [ABSTRACT FROM AUTHOR]

A total of 107 coastal environment samples collected, during the period from February to December 2002, from different sites along the seashore of Alexandria City were examined for the presence of enterohaemorrhagic Escherichia coli O157 and total colifrom bacteria (TC). Of the total examined samples, 51 (48%) were found to harbour the pathogen. The bacterium was recovered from 23 (48%) of 48 seawater, 15 (37%) of 41 fish and 13 (72%) of 18 invertebrate samples. The pathogen was detected in the environmental samples during all the sampling months. Some stations proved to be contaminated over the entire period of study; however, others were not. As a general trend, a positive correlation between TC counts and the presence of the pathogen was observed. Also, numbers of TC and the incidence of the bacterium were relatively high during the warmest months. Measures that prevent the risk of infection by such pathogen are discussed. [ABSTRACT FROM AUTHOR]

The population of Listeria monocytogenes in a minimal medium (lacking a nitrogen source) at pH 5.5 decreased logarithmically during incubation. Rate of death of the pathogen, indicated by D-values, was greatly affected by changes in the temperature of incubation (4-35°C), but to a much lesser extent by the presence of benzoic acid (3000 ppm). Injury of L. monocytogenes during incubation was equally detectable on tryptose agar containing 6% salt and McBride Listeria Agar containing 0.5% lithium chloride. A greater degree of injury was detected at the lower than the higher temperatures of incubation, but presence of benzoic acid (3000 ppm) did not seem to affect the extent of injury. [ABSTRACT FROM AUTHOR]