Effects of Direct and Indirect Sunlight on Polythene Packs, Sensory, Microbial and Chemical Properties of Sachet Water

Abstract

The use of Polyethylene or Polyethylene terephthalate (PE/PET) packaging bags for water in Nigeria has great marketing appeal to consumers. However, poor storage and display techniques could subject these products to microbial, physical and chemical deterioration. Sachet water samples commonly taken by staff and students of the Federal College of Agriculture, Ibadan were subjected to different storage conditions for three and five days. Physicochemical parameters of each water sample were determined through equilibrated devices and titrimetric or colorimetric assays, while aerobic bacteria were isolated through pour-plate method in Nutrient Agar. Exposure of sachet water to sunlight had significant effects on their physical, chemical and bacteriological properties. Highest chloride, calcium, alkalinity, hardness, sulphate and total dissolved solids (13.04 mg/L, 123.53 mg/L, 9.08 mg/L, 33.00 mg/L, 27.59 mg/L and 78.33 mg/L, respectively) were recorded in water samples exposed to indirect sunlight for 5 days. Samples stored at room temperature had the best physicochemical properties. Exposure to sunlight reduced the colony forming units of aerobic bacteria in all the water samples. Lowest bacterial count (0.33 × 103 CFU/mL) was observed in water sample exposed to sunlight for 5 days, while the highest count (55.84 CFU/mL) was recorded in samples stored at room temperature. Sensory scores of water samples ranged between 8.33 and 10.00; however, these sensory properties were not significantly affected by their exposure to sunlight for up to 5 days. Sunlight exposure negatively affected the inner surface feel of water packs, sachets appeared slimy after direct and indirect exposure. The physicochemical and microbial changes observed in sunlight-exposed sachet water samples did not influence their organoleptic acceptability. Consequently, in addition to taste and biochemical analysis, the feel of water sachets could be an indication of structural disintegration and water contamination. In order to maintain the integrity of sachet water, products should be hygienically prepared and prevented from sunlight exposure during transportation and storage.

The effects of storage time and sunlight on microplastic pollution in bottled mineral water

“…Moreover, in the same condition, storage of bottles under direct sunlight led to more than two times MPs concentration in bottled waters. According to the literature (Abboudi & Odeh, 2015; Adedire et al, 2021; Bach et al, 2014; Suhrhoff & Scholz‐Böttcher, 2016), sunlight exposure by a polymer may lead to photochemical ageing, absorbing sunlight at a wavelength of UV light spectra (≤300 nm and ≤330 nm) and increasing the water's temperature. This effect raises concerns regarding possible sources of health hazards for the consumers due to the by‐products and their migration into water (Dehghani et al, 2018; Kamarehie et al, 2019).…”

“…Jafari et al (2016) assessed the storage and sunlight effects on heavy metals released from PET bottles into the water. Adedire et al (2021) investigated the impact of direct and indirect sunlight on some microbial and chemical characterization of sachet water. Also, Bach et al (2014) assessed the chemical analysis and in vitro toxicity of materials released from PET bottles into the water due to sunlight exposure.…”

Quality assessment of different polyethylene-packaged groundwater in the Ilorin metropolis of Nigeria for compliance with standards

“…However, total hardness increased in some samples after the second month of storage, exceeding the WHO limit. The increased total hardness may signal an increased availability of metal ions in the sachet water [36]. Differences in total hardness could be attributed to varying levels of magnesium and calcium in water as influenced by the geology of its source Figure 4 shows the electrical conductivity of all sachet water samples over 4 months of storage.…”

“…The rise in chloride concentrations may be associated with possible leaching from chlorine-containing compounds into the packaged water during storage. For example, Farinu et al [36] had earlier hypothesized the possible contribution of leached chemicals, including trichloromethane from disintegrating polyethylene packaging materials, on the increased chloride concentration of stored sachet water. Chlorides are inorganic compounds resulting from the reaction between chlorine gas and metals.…”

Bacterial Contamination Levels and Brand Perception of Sachet Water: A Case Study in Some Nigerian Urban Neighborhoods

“…Another challenge with the quality of SW is storage and method of sale. Once the SW has been packaged in the factory, it is often transported in open trucks that allow exposure to sunlight, some vendors store the bags of water in outdoor cages that allow sunlight exposure while others hawk the SW in bowls containing ice and allowing sunlight exposure [21]. It is a known fact that residual chlorine in water protects public health by limiting the regrowth of microbes, however when water is exposed to sunlight, chlorine levels are likely to deplete resulting in poor water quality.…”