High-density Polyethylene Bottles Research Articles

A Simple Water Sample Storage Test for Water Isotope Analysis

Water is pivotal for human societies’ sustainability and resilience. Isotope hydrology and hydrogeology research plays an important role in understanding and managing water resources. Reliable scientific results hinge on high-quality data. Preventing water sample evaporation is essential for accurate isotopic analysis. In this study, the impacts on the quality of isotopic data were tested for the storage of water samples and the repetitive opening of a laboratory reference material (LRM) sub-sample replica during daily operation. Twenty 15 mL water samples were stored in high-density polyethylene (HDPE) bottles at room temperature and humidity to simulate storage conditions. One 60 mL water sample was collected from the same starting batch to simulate the LRM sub-sample. Each 15 mL sample was analysed once over 80 days for the isotopic composition of oxygen (δ18O) and hydrogen (δ2H). The 60 mL sample was repeatedly analysed in the same period. The data were tested to identify shifts in the isotopic composition induced by evaporative processes. The main results of the work are the following: (i) storage of the 15 mL water samples did not cause detectable evaporation in the testing period; (ii) the 60 mL δ18O values showed evidence of evaporation as proved by the positive shift of the isotopic data; (iii) the repetitive opening of the 60 mL sample was the main cause of evaporation; (iv) five openings can already cause detectable isotopic enrichment. Careful manipulation and frequent replacement of the LRM are thus necessary to prevent deterioration of the quality of the analyses.

Evaluation of the impact of natural weathering on the properties of high‐density polyethylene bottles by experimental approach

AbstractThis work presents an in‐depth experimental study aimed at assessing the impact of natural weathering on the behavior of high‐density polyethylene (HDPE) bottles. To this end, several analytical techniques were employed, including Fourier transform infrared spectroscopy (FTIR) to examine molecular changes, scanning electron microscopy (SEM) to study morphology, thermogravimetric analysis (TGA) to assess thermal properties, and tensile and compression tests to evaluate mechanical properties. The results obtained reveal significant changes in HDPE exposed to natural weathering. FTIR analysis enabled us to identify that the HDPE bottles had been subjected to an oxidation process initiated by the absorption of solar radiation during natural weathering treatments, while SEM analysis showed the presence of holes resulting from the detachment of material fragments after exposure, TGA analysis confirms the impact of natural exposure time on the decrease in the average molecular weight and chemical degradation of HDPE macromolecules, through a reduction in the initial degradation temperature and the maximum thermodegradation temperature. However, tensile and compressive tests showed a reduction in the mechanical strength of HDPE after exposure to natural conditions, with notable variations depending on environmental conditions, making the material damaged. These results enabled us to calculate the damage caused by three damage laws. These results offer important insights into the mechanisms of HDPE degradation under the influence of natural climatic factors, paving the way for the development of more resistant and durable packaging materials in the face of variable environmental conditions.Highlights The objective of this study is to analyze and describe the effects of natural weathering on high‐density polyethylene bottles. This involves evaluating the deterioration of physicochemical, mechanical, and morphological properties. Additionally, three damage laws are employed to assess the extent of damage inflicted by this material. Analytical techniques were used, including SEM, FTIR, and TGA, tensile and compressive test.

Experimental study of the degradation of HDPE packaging under accelerated thermal aging

In this work, accelerated thermal aging at different temperatures was performed on high-density polyethylene (HDPE) bottles and specimens for food packaging. The degradation of HDPE was followed macroscopically by tensile and compression tests to evaluate the decrease in mechanical properties. The data obtained from these tests are used to calculate a new static damage law and the life fraction of this polymer. A prediction of the lifetime of HDPE was determined by thermogravimetric analysis (TGA) in dynamic mode. The evolution of the crystallinity rate during accelerated thermal aging was carried out using FOURIER transform infrared spectrometry (FTIR). The results obtained show a remarkable degradation of the mechanical properties in traction and compression by calculation of the static damage, and the physical and chemical properties by the analysis of the rate of crystallinity as well as the prediction by the law of Arrhenius.

Factors Limiting Shelf Life of a Tomato-Oil Homogenate (Salmorejo) Pasteurised via Conventional and Radiofrequency Continuous Heating and Packed in Polyethylene Bottles.

Salmorejo is a tomato-oil cold puree commercialized as a "fresh-like" product requiring mild pasteurisation and chill storage to reach a suitable shelf lifetime. The objective of this study was to study the factors which limit the shelf life of salmorejo pasteurised via conventional or radiofrequency continuous heating, packed in high-density polyethylene bottles, and kept at refrigeration. The pasteurised-chilled salmorejo reached a long shelf life (4 months) compared to that of pasteurised tomato juices or purees. Mesophilic and pathogenic bacteria were easily inhibited in this acidic product. Salmorejo mainly showed oxidative and subsequent sensory changes. Initial enzyme oxidation was associated with some adverse effects (loss of vitamin C and lipid oxidation) at the first month, although there were no sensory implications. Salmorejo remained stable at the physicochemical and sensory levels for the following 3 months, though colour and viscosity changes could be measured with instruments. Between the fourth and fifth month, salmorejo showed clear signs of deterioration, including changes in appearance (slight browning and loss of smooth surface), odour/flavour (loss of freshness and homogenisation), and consistency (thinning trend). The shelf life of salmorejo is limited by long-term oxidative deterioration and their sensory implications.

Building a community-scale plastic recycling station to make flower pots from bottle caps

Plastic waste is increasing worldwide, contributing significantly to pollution and global warming. Our department uses at least 50 plastic water bottles daily; these bottles can be reused to manufacture other products. Recycling plastic waste produces various products, including garden sets for kids, bricks, roof tiles, key holders, and flowerpots. Through this project, we contribute to the fight against pollution caused by plastic waste by developing an easy-to-use plastic processing system. We create these valuable products using plastic collected from landfills. We present an open-source system that can be easily built by a technical team to create an ecosystem. We use the project as a mobile educational model to demonstrate the recycling mechanism and to foster a community recycling culture. The following procedures are included in this study. High-density polyethylene bottle caps are washed and dried before shredding in a shredder to produce flakes. Plastic flakes are fed into an extruder, which heats and transforms them into a homogeneous mass. This molten plastic is molded into the shape of a flowerpot using a die. Pots are great products to obtain from discarded plastic caps due to their strength. Following the fabrication of the entire system, numerous tests are performed to improve the design and obtain the desired specifications, resulting in appealing end products. In our facilities, flowerpots are made from consumer bottle caps and used to grow aloe.

Application of inverse problems in diffusivity coefficient estimation of polymeric packaging materials and food shelf-life determination

An effective analysis method with multiple accelerant factors is needed for rapid shelf-life determination for foods. This study aimed to investigate the effect of environmental oxygen pressure on oxygen diffusivity in polyethylene terephthalate (PET), high-density polyethylene (HDPE) and polypropylene (PP) bottles. The bottles were placed in custom-made high-pressure (10–30 psig) chambers with a 100% oxygen environment after filled with water and flushed with nitrogen to reduce the internal oxygen level below 2%. Bottles were subjected to three pressure levels and the accumulation of headspace and dissolved oxygen was used to estimate the diffusivity with the inverse problems approach. Modelling of diffusion was performed by numerically solving Fick’s law and the sequential estimation of the diffusion coefficient was performed based on the Gauss minimization method. The oxygen diffusion coefficient of PET, HDPE and PP was in the range of 0.78−1.16x10−13 m2s−1, 0.14−0.46x10−13 m2s−1 and 0.59−14.09x10−16 m2s−1, respectively. The application of oxygen pressure significantly increased the rate of oxygen transfer for all packaging materials compared to the control samples at ambient pressure. The application of inverse problems enabled the determination of the diffusion coefficient of oxygen with minimal errors and small confidence intervals. The use of elevated pressure and temperature as accelerants has potential application in rapid shelf-life determination of foods.

Impact of Dumpsites on Groundwater Contamination in Selected Settlements in Irewole and Isokan Local Government areas, Osun State, Nigeria

This study examined the spatio-temporal variation in the physico- chemical characteristics of ground water across the study area. This was with a view to determining the impact of dumpsites on ground water quality in the study area. Ground water samples were taken twice (once in the dry season and once in the wet season). These samples were taken from wells within 150 m proximity of a dumpsite using 1 litre high density polyethylene bottles. A control point was purposely picked, 1 km away from any noticeable dumpsite. The water samples were analyzed for physical and chemical parameters according to APHA, 1992 standard. The result of Analysis of Variance between values exhibited at the sampled points in Apomu and Ikire showed that there was no statistically significant difference in ground water pH values between the two communities in both wet (F = 0.102, P > 0.05) and dry (F = 0.471, P > 0.05) season. The result showed that the distance of the sample points to the dumpsite did not have a direct influence on water quality in that some parameters that were tested were found to exist more in the control samples than in the mean of the experimental samples. The results also showed that some of the tested parameters existed in higher quantities than both Nigerian and WHO standards for drinking water quality. The study concludes that the dumpsites in the study area has led to contamination of ground water as a result of leachate percolation from the dumpsites

Stability of levothyroxine tablets in blister packaging versus bottles and vials under simulated in-use conditions

IntroductionLevothyroxine, the standard-of-care treatment for hypothyroidism, is susceptible to degradation when exposed to light and moisture and is an FDA-designated narrow therapeutic index drug. In this report, we examined how different packaging (e.g., cold form blister packs, manufacturer’s bottles, or pharmacy amber vials) affects the physicochemical integrity and potency of levothyroxine in conditions simulating real-world patient use.MethodsIn part 1 of this study, we evaluated changes in the physicochemical properties (e.g., moisture gain, hardness, and disintegration time) of levothyroxine tablets stored in high-density polyethylene (HDPE) bottles, amber vials, and blister packs when exposed intermittently to different relative humidities (RH), 25 °C/75% RH and 25 °C/90% RH for 90 days, or 54 °C/75% RH continuously for 2 days. In part 2 of the study, we compared the potency of levothyroxine tablets in bottles and aluminum/aluminum cold form blister packs exposed to 28 °C/65% RH intermittently over 105 days and continuously over 30 days.ResultsMoisture content, hardness, and disintegration time were relatively unchanged for blister-packaged levothyroxine tablets under all conditions studied. Conversely, the physicochemical properties of tablets stored in amber vials and bottles were altered over time. Levothyroxine potency remained relatively consistent for blister-packaged tablets (100.8% at baseline, 99.6% at day 105) and decreased for bottled levothyroxine (101.4% at baseline to 93.9% at day 105).ConclusionLevothyroxine packaging can influence tablet integrity. Blister packages preserved physicochemical properties and potency better than bulk bottles. Additional studies are needed to determine the impact of packaging and changes in tablet integrity on patient outcomes.

Environmental Impacts of End-of-Life Options of Biobased and Fossil-Based Polyethylene Terephthalate and High-Density Polyethylene Packaging

Plastic waste production increasingly causes environmental pollution. However, end-of-life (EoL) research often lacks detail and timeliness and fails to integrate the end-of-life option into a product’s life cycle in a systemic perspective. This study addresses these knowledge gaps, by applying an improved anticipatory consequential life cycle assessment (LCA) approach. Reuse, mechanical and chemical recycling options were compared for (biobased and fossil-based) high-density polyethylene (HDPE) and polyethylene terephthalate (PET) plastic shampoo bottles in the European context using three types of impact categories: climate change, fossil resource scarcity and mineral resources scarcity. The completeness and detail of EoL were increased by modelling the polymer reprocessing within the collection system including all transport distances, while timeliness was improved by implementing the data applicable for the time of implementation of EoL options in the future. The results show that the reuse option has the largest benefits on climate change impact, and on fossil and mineral resource scarcity for both HDPE and PET, for both biobased and fossil plastics. Furthermore, all EoL options cause a net reduction in all climate change, fossil and mineral resource scarcity thanks to the avoided impact of virgin plastic. Finally, the improved LCA approach, utilized in this study, includes plastic production, use and EoL in one assessment, and thus can provide valuable information for adjusting policy and regulations for plastic manufacturers in their production of new virgin plastic polymer, as it requires alignment with its use and EoL options.

The Physical Characterization and Terminal Velocities of Aluminium, Iron and Plastic Bottle Caps in a Water Environment

Aluminium, iron and plastic are materials which are extensively used at both industry and individual levels. However, significant amounts of aluminium, iron and plastic end up in the environment. Specifically, bottle caps made of these materials are often thrown away, with or without bottles, and appear among the common plastic debris entering the world’s oceans and beaches. More than 20 million bottle caps and lids have been identified during beach-cleaning campaigns over the last 30 years. To recover bottle caps from the shores, conventional technologies can be used. In this paper, the physical properties of used metal and plastic bottle caps were examined and related to the settling and rising velocities of the caps, as well as their drag coefficients and hydrodynamic modes in water environments, with respect to gravity separation. The sample contained aluminium, iron, high-density polyethylene (HDPE), low-density polyethylene (LDPE), and polypropylene (PP) bottle caps. The findings revealed that the density differences between the bottle caps resulted in the terminal settling velocities of aluminium and iron particles, which were significantly higher than the rising velocities of the plastic caps. The results allowed us to design a flowsheet for bottle cap recovery from beach coasts in order to reduce environmental impact and produce add-on plastic and metal products.

Moisture and oxygen barrier properties of glass, PET and HDPE bottles for pharmaceutical products

The purpose of this study was to evaluate the influence of the material and volume/different finish diameters in the moisture and oxygen barrier properties for bottles for pharmaceutical products. Samples of glass, polyethylene terephthalate (PET) and high-density polyethylene (HDPE) bottles with different volumes (30, 60 and 120 cm3) and finish diameters (18, 24 and 28 mm) were studied. It was previously verified that the integrity of the closure was not dependent on the torque applied to the polypropylene (PP) cap and not influence the barrier properties of the bottles. Provided integrity of the cap for all analyzed samples, water vapor transmission rate (WVTR) of glass increased with increase in finish diameter for the same bottle size, due to a large area exposed for moisture permeation through the PP cap. WVTR of PET and HDPE are dependent by the bottle size and its surface area since moisture permeability occurs preferentially by the bottle. The influence of the material in the moisture barrier properties have been confirmed by the WVTR results obtained for the same bottle volume (30cm3/24 mm) with average values of 0.07, 9.9 and 0.8 mg.day−1.bottle−1 at 40 °C/75%RH for glass, PET and HDPE, respectively. Glass represents the greatest oxygen barrier, followed by PET and HDPE for the same bottle size.

Monitoring Rainwater Properties and Outdoor Particulate Matter in a Former Steel Manufacturing City in Romania

Wet deposition is influencing air quality because air pollutants are washed away from the surrounding air. Consequently, particulate matter and associated compounds are transported in the rainwater and enter into soil, surface waters, and groundwater. Nonpoint sources of heavy metals from stormwater runoff have increased in urban areas due to industrialization and the increasing impervious surfaces. In this work, we present an assessment of the rainwater composition regarding the nutrients and other physicochemical characteristics measured in three locations selected in Targoviste city, Romania, a city that had a specialized steel factory and important metallurgical facilities. The rainwater was collected using three PALMEX rain samplers and then was transferred to high-density polyethylene bottles and analyzed using ICP-MS. PM2.5 concentrations were also monitored continuously using optical monitors calibrated using a gravimetric sampler. A detailed analysis of the heavy metals content in rainwater and PM was presented for the pollution episodes occurring in October and November 2019. Backward trajectories were computed using the HYSPLIT model for these periods. The results showed that the PM2.5 ranged from 11.1 to 24.1 μg/m3 in 2019, while the heavy metals in collected rainwater were (µg L−1): 0.25 (Cd) − CV = 26.5%, 0.10 (Co) − CV = 58.1%, 1.77 (Cr) − CV = 24.3%, 377.37 (Ni) − CV = 27.9%, 0.67 (Pb) − CV = 74.3%, and 846.5 (Zn) − CV = 20.6%. Overall, Ni, Pb, Cr, and V had significant correlations between the concentrations from rainwater and PM. Negative associations were found between precipitation events and heavy metals both from rainwater and PM, but only a few showed statistical significance. However, this could explain the “washing” effect of the rain on the heavy metals from PM2.5. The potential sources of nitrogen in the rainwater collected in Targoviste could be from burning fossil fuels and the soils, including both biological processes and fertilization resulting from the intensive agriculture in the piedmont plain in which the city is located. Based on the results, rainwater monitoring can constitute a reliable method for air quality characterization. Additional research is required to better understand seasonality and sources of heterogeneity regarding the associations between PM and rainwater composition.

Choosing an Effective Compatibilizer for a Virgin HDPE Rich-HDPE/PP Model Blend.

The most widely used commodity polymers in the rigid packaging industry are polypropylene (PP) and high-density polyethylene (HDPE). For example, blow molding grade of HDPE as a bottle and injection molding grade of PP as a cap are often used to produce detergent bottles. Therefore, the recycled HDPE bottles from post-consumer waste include PP as a contaminant originated from PP bottle caps. To simulate mechanical recycling of bottle waste, the mechanical properties of HDPE-rich-HDPE/PP virgin model blend were studied. For compatibilization, ethylene-based olefin block copolymer, propylene-based olefin block copolymer, ethylene propylene random copolymer, and styrene-butadiene-styrene triblock copolymer were chosen as potential compatibilizer candidates. Contact angle measurements, morphological analysis, adhesion tests of compatibilizer candidates to polymer blend components and the tensile as well as tensile impact properties of the ternary blends were studied. It was found that the ethylene-based olefin block copolymer was the most effective compatibilizer resulting in a return of mechanical properties to those of neat vHDPE due to its ability to encapsulate dispersed vPP particles in a vHDPE matrix (core-shell morphology) and the best adhesion to polymer blend components.

Uncertainty Analysis of Measurement of N-hexane Nonvolatiles in Oral Solid Medicinal High-density Polyethylene Bottles

Uncertainty Analysis of Measurement of N-hexane Nonvolatiles in Oral Solid Medicinal High-density Polyethylene Bottles

Development and testing of a multi-element ICP standard

Determination of the calibration dependence of spectrometers’ output signal on the content of the measured elements is of great importance for the metrological assurance of the high-precision inductively coupled plasma (ICP) massspectrometry and optical emission spectrometry methods. This paper presents the results of a study on establishing the certified values of reference material of composition of multi-element solution of metals intended for inductively coupled plasma methods (ICP-CRM solution Multi 1). The reference material (RM) is a solution with certified values of the mass fraction of metals: barium, cadmium, cobalt, lithium, lead, and zinc. The solution was packed in high-density polyethylene bottles with the capacity of 4, 8, 15, 30, 60 and 125 cm 3 . The certified value of the mass fraction of metals in the solution was established by the calculation and experimental procedure and confirmed by the GET 217-2018 State Primary Standard of Unit of Mass Fraction and Unit of Mass (Molar) Concentration of Inorganic Components in Aqueous Solutions Based on Gravimetric and Spectral Methods. The permissible certified values of the mass fraction of metals in the developed ICP-CRM are shown to range from 900 mg/kg to 1100 mg/kg. The authors have embarked on the study of the reference material by testing RMs for long-term stability and determination of the RMs’ expiration date. It is assumed that the expanded uncertainty of measurements of the certified value of the mass fraction of metals in the solution of the multi-element ICP-CRM solution Multi 1 will not exceed 0.5 %. The ICP-CRM solution Multi 1 can be used for ensuring the metrological traceability of measurements in inorganic analysis using ICP-MS and ICP-OES to the GET 217-2018. The developed solution will also allow one of the main advantages of these methods to be applied in routine analysis, namely the ability to quickly and simultaneously measure several elements in samples.

Electron beam irradiation inactivation of Bacillus atrophaeus on the PET bottle preform and HDPE bottle caps with different original colonies

In this study, electron beam (EB) irradiation was used for the inactivation of Bacillus atrophaeus on the surface of polythylene terephthalate (PET) bottle preform and high-density polyethylene (HDPE) bottle caps. The effects of EB irradiation doses (0,1,3,5,7,9 kGy) and original inoculated colony counts (101,102,103,104,105,106,107 CFU/sample) were evaluated on the residues of B. atrophaeus and the quality attributes of bottle caps and preform. A Weibull model for simulating the sterilization data was established by fitting the microorganism inactivation curves with a high coefficient (R2 > 0.93). The reductions of the microorganism lethal rate (log N/N0) up to 7.11log, 6.21log, 5.59log were shown on 38 mm bottle cap, 28 mm bottle cap and bottle preform with the original colony counts of 107 CFU/sample after the EB irradiation treatment at 9 kGy, respectively. The b* values of bottle preform and caps were slightly affected and the highest color change was observed for 28 mm bottle cap treated by 9 kGy EB irradiation, which resulted in a decrease of b* value from −39.86 ± 0.15 to −41.25 ± 0.42. Nevertheless, EB irradiation could be applied in the decontamination of PET bottle preform and HDPE bottle caps under reasonable doses.

Case Study Comparing Effects of Microplastic Derived from Bottle Caps Collected in Two Cities on Triticum aestivum (Wheat)

As plastic has become an integral component of daily life, microplastic has become a ubiquitous, unavoidable constituent of nearly all ecosystems. Besides monitoring the amount and distribution of microplastic in the environment, it is necessary to understand the possible direct effects, especially toxicity and how it is affected by environmental factors where it is discarded. The present study investigated how microplastic derived from high-density polyethylene bottle caps collected in two climatically different cities, i.e., Singapore (tropical rainforest climate) and Lahti, Finland (continental climate), affected the essential agricultural grain crop, Triticum aestivum (L.). Wheat seedlings were exposed to microplastic derived from these collected bottle caps, as well as new and artificially aged caps, for seven days. Morphological parameters, such as root and shoot length and oxidative stress development, were measured. Exposure to microplastic derived from the caps resulted in reduced seedling root and shoot lengths compared to the controls, as well as enhanced lipid peroxidation and catalase activity. With all parameters tested, microplastic derived from Lahti bottle caps exhibited more severe effects than Singapore, which was similar to that elicited by new microplastic. The Singapore microplastic had possibly leached its toxic substances before collection due to accelerated degradation promoted by the prevailing warmer climate conditions.

THE EFFECT OF PACKAGING TYPE AND STORAGE TEMPERATURE ON THE SHORT TERM STABILITY OF ELECTROLYTIC CONDUCTIVITY REFERENCE MATERIALS

In this work, monitoring the effect of packaging type and storage temperature on the short term stability of calibration standard solution KCl 1 M were conducted. The KCl 1M were packaged in two types of packaging i.e., high-density polyethylene (HDPE) and glass bottle. The effects of packaging type and storage temperature were monitored for four weeks at 25 °C and 40 °C. The conductivity values of KCl 1 M in the HDPE and glass bottle were 111.61 mS/cm and 111.62 mS/cm, respectively. The results indicated that the KCl 1M solution at 25 °C in both HDPE and glass bottle were found to be good in short term stability and there was no significant different between the two packaging types. At temperature of 40 °C, however, short term stability of the KCl 1 M in a glass bottle was better than the HDPE bottle.

Child preferences and perceptions of fluid milk in school meal programs

School meal programs in the United States feed approximately 30 million children each day and account for the majority of child milk intake. Dairy consumption during childhood and adolescence has lasting effects on lifelong health status, so it is important for schools to ensure adequate consumption in this life stage by offering an appealing product. This study identified the intrinsic and extrinsic attributes that influence children's perceptions, attitudes, and consumption of fluid milk at school, especially as they relate to fluid milk packaging. An online choice-based conjoint survey (n = 211) and four 1-h focus groups (n = 31) were conducted with child milk consumers ages 8 to 13 yr to evaluate extrinsic attributes. The survey evaluated milk package attributes including packaging type, front-of-package graphics, package color, and labeled milk fat content. Focus group topics included preferences, usability, health, taste of fluid milk, and milk consumption habits. To evaluate intrinsic properties related to packaging, 3 varieties of milk (unflavored fat-free, unflavored low-fat, and chocolate-flavored fat-free) were produced and packaged in polyethylene-coated paperboard cartons, polyethylene terephthalate (PET) bottles, and high-density polyethylene (HDPE) bottles (all 250 mL). After 10 to 13 d of storage at 4°C under dark conditions, milks were evaluated by descriptive analysis and child acceptance testing (ages 8-13 yr; n = 126, 122, and 126 for each variety, respectively). Extrinsically, package type was the most important attribute to children, but graphics, nutritional labeling, branding, package size, and overall familiarity also drove preferences. The ideal milk packaging build from the conjoint survey was an HDPE bottle with blue-colored packaging and a cow graphic, labeled as low-fat milk. Intrinsically, all varieties of milks packaged in paperboard cartons developed package-specific flavors, including refrigerator/stale and paperboard, after 10 d of storage. These off-flavors were not detected in HDPE- or PET-packaged milks. For unflavored milks, child consumers preferred the flavor of PET- or HDPE-packaged milks over cartons, regardless of milk fat content, but preferences were not distinct for chocolate-flavored milk. The results of this study demonstrate that children's liking and preference for milk are driven by both intrinsic and extrinsic factors and suggest that improvements are needed to increase acceptance of milk currently served in school meal programs.

Reimagining the milk supply chain: Reusable vessels for bulk delivery

Milk packaging has been analysed multiple times in pursuit of finding the most appropriate vessel from an environmental point of view. Research has concentrated on commercially available containers of 0.5 – 2.5 litres, usually made from High-Density Polyethylene (HDPE), Polyethylene Terephtalate (PET), paper-based cartons, or glass, with some studies considering a reuse scheme for glass bottles. Whilst applicable for household delivery, such a reuse scheme is not practical for delivery to cafés where large volumes of milk are used every day; little information is known about transportation of bulk volumes of milk in bigger vessels such as steel churns. This study compares a proposed milk supply chain using a mix of reusable stainless steel churns and reusable glass bottles with the current supply chain that uses single-use HDPE bottles, for transportation of milk to 10 cafés belonging to The University of Sheffield. A cradle-to-grave life cycle assessment (LCA) is conducted using data obtained from the university and Our Cow Molly, a local dairy farm which delivers milk to the university. Sensitivity analysis was performed around the recycling rate of plastic bottles, water consumption for churn cleaning, the reuse rate of glass bottles and churns and the source of the on-farm electricity. The study suggests that the greenhouse gas emission can be lowered by approx. 6.5 tons of CO 2 equivalent annually if the reuse scheme is applied (this equates to a 65% reduction for the processes analysed). Considerable savings are also reported in categories such as water consumption, fossil resources depletion and cumulative energy demand. The reuse scheme is, however, likely to induce a similar or higher mineral resource use and higher environmental damage in the marine eutrophication category due to water treatment. Production of plastic bottles in the plastic scenario and maintenance and transport on the reusable side are the main contributors to the environmental impact. Further improvements in the reuse scenario could be achieved by reducing the amount of water used for cleaning and hence the electricity demand for water heating. The reuse scheme could also benefit environmentally from using an electric refrigerated van instead of a diesel vehicle.