Initial Microbial and Physicochemical Changes (0–48 h) in Freshly Extracted Orange and Pineapple Juice from Commercial Vendors as Influenced by Different Packaging Materials and Storage Temperatures
Omorodion, Nnenna J. P. *
Department of Microbiology, University of Port Harcourt, PMB5323, Rivers State, Nigeria.
Osakuade, Felicia O.
Department of Microbiology, University of Port Harcourt, PMB5323, Rivers State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
This study investigated the effect of packaging material (glass vs. plastic) on the physicochemical and microbiological quality of freshly prepared orange and pineapple juices stored at ambient and refrigerated temperatures for a short term. Microbiological analysis revealed that juices stored at ambient temperature had higher microbial loads than those stored under refrigeration. Total bacterial counts (TBC) ranged from 3.00–3.70 log₁₀ CFU/ml in ambient-stored juices and 3.00–3.30 log₁₀ CFU/ml in refrigerated juices. Coliforms were detected mainly in plastic-packaged juices under ambient conditions, ranging from 0–2.32 log₁₀ CFU/g, and 0–1.98 log₁₀ CFU/ml under refrigerated conditions. Staphylococci were detected only in plastic-packaged orange juice stored at ambient temperature. Total fungal counts (TFC) in glass-packaged juices ranged from 1.70–2.02 log₁₀ CFU/ml (ambient) and 1.48–2.04 log₁₀ CFU/ml (refrigerated), while in plastic-packaged juices, TFC ranged from 1.93–2.40 log₁₀ CFU/ml (ambient) and 1.54–2.16 log₁₀ CFU/ml (refrigerated), all within stipulated standards.Six bacterial genera were identified: Lactobacillus (42.9%), E. coli (14.3%), Staphylococcus aureus (14.3%), Enterococcus sp. (14.3%), Bacillus sp. (7.1%), and Enterobacter sp. (7.1%), with Lactobacillus dominating pineapple juice due to its tolerance to acidic and sugary environments. Five fungal species were isolated: Saccharomyces sp. (47.1%), Candida sp. (23.5%), Aspergillus sp. (11.8%), Penicillium sp. (11.8%), and Rhizopus/Mucor (5.9%). Physicochemical analysis showed a greater decrease in pH in ambient-stored juices compared to refrigerated samples. Vitamin C content decreased from 42.1 mg/100 ml to 35.8 mg/100 ml in glass-packaged juice and from 42.0 mg/100 ml in plastic-packaged juice. Color intensity increased progressively in all samples. These findings indicate that both storage temperature and packaging material critically influence short-term juice quality. The study recommends glass packaging combined with refrigerated storage to ensure optimal microbial safety, chemical stability, and sensory quality of commercial fruit juice.
Keywords: Packaging material, glass bottle, plastic bottle, ambient storage, refrigerated storage, microbiological quality, physicochemical properties, orange juice, pineapple juice, shelf life