Controlling of Mycobacterium by Natural Degradant-Combination Models for Sequestering Mycolic Acids in Karish Cheese

Degradation of the mycobacterial complex containing mycolic acids (MAs) by natural bioactive compounds is essential for producing safe and value-added foods with therapeutic activities. This study aimed to determine the degradation efficiency of natural organic acid extracts (i.e., citric, malic, tartaric, and lactic), quadri-mix extract from fruits and probiotics (i.e., lemon, apple, grape, and cell-free supernatant of Lactobacillus acidophilus), and synthetic pure organic acids (i.e., citric, malic, tartaric, and lactic), against MA in vitro in phosphate buffer solution (PBS) and Karish cheese models. The degradation effect was evaluated both individually and in combinations at different concentrations of degradants (1, 1.5, and 2%) and at various time intervals (0, 6, 12, 24, and 48 h). The results show that MA degradation percentage recorded its highest value at 2% of mixed fruit extract quadri-mix with L. acidophilus and reached 99.2% after 48 h both in PBS and Karish cheese, unlike other treatments (i.e., citric + malic + tartaric + lactic), individual acids, and sole extracts at all concentrations. Conversely, organic acid quadri-mix revealed the greatest MA degradation% of 95.9, 96.8, and 97.3% at 1, 1.5, and 2%, respectively, after 48 h. Citric acid was more effective in MA degradation than other acids. The fruit extract quadri-mix combined with L. acidophilus-fortified Karish cheese showed the highest sensorial characteristics; hence, it can be considered a novel food-grade degradant for MA and could be a promising biocontrol candidate against Mycobacterium tuberculosis (Mtb) in food matrices

Evaluation of the Prevalence of <i>Staphylococcus aureus</i> in Chicken Fillets and Its Bio-Control Using Different Seaweed Extracts

This study aims to assess the occurrence of Staphylococcus aureus in chicken fillets and to control its growth using various lyophilized seaweed extracts (i.e., Halimeda opuntia (HO), Actinotrichia fragilis, and Turbinaria turbinata) by an agar disk diffusion assay in vitro. Results showed that prevalence of S. aureus in breast and thigh samples reached of 92% and 84%, respectively. Lyophilized HO extract was the only seaweed that showed the antibacterial activity against S aureus with a significant difference at p 50 was recorded at 55.36 μg/mL, whereas cytotoxic IC50 of the lyophilized HO extract on peripheral blood mononuclear cells (PBMCs) was 33.7 µg/mL; a higher IC50 of HO extracts permits their use as a safe food additive in meat products. Moreover, total phenolic compounds and total flavonoids compounds recorded 20.36 ± 0.092 and 16.59 ± 0.029 mg/mL, respectively. HPLC analyses of phenolic compounds profiles exhibited many bioactive substances and the higher ratio was daidzein with 10.84 ± 0.005 µg/mL and followed by gallic acid with a value of 4.06 ± 0.006 µg/mL. In a challenge study, chicken fillet (CHF) experimentally inoculated with S. aureus (ST) and treated with the lyophilized HO algal extract at 4% and 6% (CHF/ST/HO) showed a complete reduction of S. aureus count on the 6th and 4th days in chicken fillet stored at 4 °C, respectively. Moreover, CHF/ST/HO at 4% and 6% of HO extract enhanced the sensory attributes of grilled un-inoculated chicken fillet. Thus, lyophilized HO extracts are promising antibacterial and antioxidant candidates in the chicken meat industry