ABSTRACT
Aims: To evaluate the effect of packaging materials and storage temperatures on the microbiological quality of Hibiscus sabdarifa drinks produced with: 1) commercial pineapple flavour (HCPF) and; 2) Phoenix dactylifera (38%) and pineapple extract (2%) (HPPE). Methodology: Pasteurized drinks packaged in polyethylene sachets, plastic and glass bottles were stored at refrigeration (4.4±2oC) and ambient (25±2oC) temperatures for 27 and 9 days respectively. Results: There was significant (P≤0.05) decrease in total bacterial count in HCPF (≤4.51-≥2.14 Log10CFU/ml) with higher death rate (0.06) in plastic bottles at 4.4±2oC while at 25±2oC it increased significantly (P≤0.05) in HPPE samples (4.00-≤4.95 Log10CFU/ml) with least growth rate in plastic bottles (0.02). Yeast count at 25±2oC (1.28 – 2.15 Log10CFU/ml) was significantly (P≤0.05) higher than at 4.4±2oC (1.00 – 1.60 Log10CFU/ml) and drinks in plastic bottles had the least growth rates (≤0.03). Coliform (2.04 – 2.59 Log10CFU/ml), Escherichia coli (2.00 – 2.93 Log10CFU/ml) and Staphylococcus (2.00 – 2.50 Log10CFU/ml) sparingly detected, were unable to grow in the drinks with greater inhibition at 25±2oC in all packaging materials. No growth of Salmonella was observed in the drinks. Glass bottles favoured more microbial growth but the levels were satisfactory for all packaging which is indicative of microbiological safety. Conclusion: Any of the packaging material can be used for packaging of Hibiscus sabdarifa drinks with storage at refrigeration temperature for ≤ 21 days. It is informative to both consumers and producers that the then wasted pineapple peels can serve as an ingredient in Hibiscus sabdarifa drink production.
ABSTRACT
This study investigated the probiotic potentials of seven lactic acid bacteria (LAB) strains at different temperatures, pH, and bile salt concentrations. Their antimicrobial activity and antibiotic susceptibility were also determined. There were significant (P˂0.05) differences in the LAB growth at 45-650C with viable counts ranging from 4.28-8.34 Log10 Cfu/ml after 48 h. The LAB strains showed significant (P˂0.05) increase at pH 2, 2.5 and 3 after 3 and 6 h. L. parabuchneri LMG was viable at 45 and 65oC with 99.30 and 65.00% survival respectively. The LAB showed high resistance to 0.3% bile salt at 97.90%. L. plantarum CIP was viable with 95.40% survival at pH 3.0 after 3 h. All the LAB strains were susceptible to cefuroxime (20 µg/ml) and erythromycin (10 µg/ml) at 13.00-45.00 mm zone of inhibition (ZOI). They had strong antimicrobial activity against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 9027 and Listeria monocytogenes ATCC 15313. Leuconostoc mesenteroides LM and L. brevis ATCC inhibited the five tested food borne pathogens with ZOI varying from 8.00-26.00 mm. The results from this study showed that the LAB strains isolated from fermented foods had probiotic potential and can be used for research and commercial purposes.