1. Introduction
Single-use plastics, also known as disposable plastics are commonly used for packaging and are intended to be used once and then discarded or recycled [
1]. Plastic is commonly utilised for goods such as plastic bags, straws, disposable bottles, food containers, and others, due to its desirable aspects, such as being lightweight, strong, inexpensive, and versatile [
2]. Packaging waste is among the most pressing global environmental issues [
3] because packaging accounts for extensive plastic use. Most food packaging is designed for single-use and is not recycled. After plastic packaging materials have served their purpose, most are disposed of as waste [
4].
The production, consumption, and management of single-use plastic food containers poses problems to human health and the environment. Single-use plastics pose even more significant hazards since they degrade into smaller particles (microplastics) and eventually infiltrate the water and food chain [
5]. Plastic waste clogs sewers, causing floods and disease, and it may also find its way into the food chain if consumed by livestock [
1]. Microplastics can enter the human body via the digestive tract through food consumption; microplastics have been found in human faeces [
6]. In addition, microplastics can leak from plastic bottle caps [
7] and plastic teabags [
8]. Plastics might release several chemicals, such as bisphenol A (BPA), phthalate, and styrene that accumulate in the human body and impair organ function [
9]. Phthalate is used for plastic food wrapping. It is an “endocrine disruptor” that interferes with hormone production [
10].
The world has most recently produced 275 million tonnes of plastic waste, exceeding the previous record of 270 million tonnes [
11]. In 2019, Malaysians generated plastic waste at a rate of 16.78 kg/person/year and higher, compared to countries such as China, Indonesia, Philippines, Thailand and Vietnam [
12]. In Malaysia, the consumption of single-use plastics and packaging for consumer goods has gradually increased over the past few decades.
Overcoming the elimination of single-use plastics is one of the biggest ecological problems in recent times. While there is a sense of urgency and increased attention on plastics as an environmental issue by industry and governments, there is a gap concerning public knowledge data, including food hawkers’ data, for supporting the plastic reduction program. Understanding the broader background regarding food hawkers’ knowledge concerning environmental issues is also essential to reducing excessive plastic use. Environmental knowledge can be defined as the ability to identify several symbols, concepts, and behavioural patterns that are related to environmental protection [
13]. Some studies have found that people with more knowledge of environmental issues are likely to demonstrate pro-environmental behaviour [
14]. A transtheoretical model explained the stages that are involved for behavioural change to occur. It describes six stages of behavioural readiness: pre-contemplation, contemplation, preparation, action and maintenance [
15]. Knowledge may affect the readiness of the individual to support pro-environmental behaviour, and possessing correct knowledge has been shown to predict pro-environmental behaviour [
16].
Past studies mostly stressed environmental concerns, such as ocean pollution, waste generation, and isolated health effects due to plastic use. Research that was carried out on food hawkers emphasised food safety and food hygiene, with very few studies focusing on using single-use plastics as food containers.
One example of a study focusing on single-plastic usage as food containers was a study on single-plastic usage using a questionnaire examined the perception of plastic packaging that is used to pack hot foods among food hawkers at the night market in Malaysia. The questionnaire was adapted from related prior studies with a questionnaire validation process that was carried out by selected panel experts with an acceptable Cronbach alpha between 0.55 and 0.89 [
17]. The triggering factor of this study was the awareness of cancer triggers among Malaysians related to the health hazards of plastic leaching chemicals into food. Our study evaluates the general single-use plastic of food containers that hold hot food, desserts, and drinks. We also include the health impacts of plastic use on high-risk populations, such as babies, children, and pregnant women, as well as the fate of plastic, chemical hazards in plastic, plastic’s environmental impact, and laws that are related to plastic usage. Another study involved 300 food handlers in Egyptian universities on KAP and focused on a selected plastic-type food contact material. This study utilized a validated survey instrument with a good internal consistency of Cronbach’s alpha value of more than 0.7 [
18].
Given the lack of questionnaires concerning street food hawkers’ knowledge on the single-use plastics reduction programme and the absence of a Malay questionnaire, it is critical to construct a valid and psychometrically sound questionnaire. In addition, previous studies on plastic-use knowledge focused on consumers as the target population, while few studies targeted the food hawkers. Survey-based studies are important tools in social, medical, economic and behavioural research and questionnaires are used to measure a variety of information provided by the participants As a result, in establishing the quality and scientific worth of any survey-based research, the use of a well-designed questionnaire is critical [
19]. Designing a questionnaire is crucial in determining only the relevant items that reflect specific constructs to be measured in research, and questionnaire validation is a crucial step to ensure quality responses and results [
20].
This study aims to develop and validate a new questionnaire to assess the knowledge of street food hawkers in Kelantan, in order to support the single-use plastic reduction program. This study can help to determine public acceptance and support for the plastics reduction program. Food hawkers will experience changes in their plastic-use system because they use plastics for business and might thus be the ones to initiate the plastic reduction program. It is evident that any improvements in plastic use must be economically and technically feasible and socially acceptable [
21]. The questionnaire must also be tailored to the local culture, beliefs, and habits to capture valuable comparative data. Validity and reliability studies are essential to increase questionnaire credibility as a research tool to produce valid data. They help to provide good quality data with high comparability and credibility, allowing generalisation for a broader population.
4. Discussion
The main aim of this study is to develop and validate a new culturally acceptable questionnaire to assess the knowledge of street food hawkers, in order to support the single-use plastics reduction program in Kelantan, Malaysia. This questionnaire was built in Malay language to make it culturally acceptable.
Generally, the items in this psychometric tool were relevant, understandable, and discriminating between overall best and overall worst candidate as evidenced by the difficulty parameters between −3 and +3 (b) and discrimination parameters (a). An IRT analysis showed a good amount of information on knowledge given by the test between a −3 and +3 ability range from the final 22 items. In our analysis, 86.7% of knowledge information could be provided on the assessment of knowledge on single-use plastic by the food hawkers that were studied. Moreover, questions that were too hard or too easy for examinees would provide little information about their abilities and so they were removed in our analysis. However, two items exceeded the difficulty index cut-off point value, which were KG2 (b = −3.06) and item KG3 (b = −3.48). Both items were kept, as their information was important in the assessment of the general knowledge of single-plastic use among hawkers. In this study, the item showed a good discrimination index between 0.8 and 2.36. The marginal reliability was 0.77, showing that this questionnaire is a reliable tool to be used to estimate the knowledge of street food hawkers, in order to support the single-use plastic reduction program.
This study demonstrated that the final version of the knowledge domain showed good psychometric properties with relevant content, and a good response process with internal validity evidence. The initial 58 knowledge items in this questionnaire were proposed in six domains but underwent tremendous item removal, involving a total of 32 items removed and 22 items remaining. All the items were grouped in a single domain with the aim of producing a comprehensive, clearly defined questionnaire, non-redundant items, and a non-exhaustive tool. IRT can be used to evaluate the psychometric properties of an existing scale and its items, to optimally shorten the scale when necessary, and to evaluate the performance of the reduced scale. When used appropriately, IRT modelling can produce precise, valid, and relatively brief instruments, resulting in minimal response burden [
38]. However, the psychometric properties in this study could not be compared to previous study on the knowledge domain on the single-use plastic food container because of inadequate information and the different method that was used for the knowledge assessment [
17,
18,
44].
There are several strengths of this study. First, to the best knowledge of the researchers’ team, this study is one of the first published studies on the development and validation of the knowledge of street food hawkers, in order to support the single-use plastics reduction program in Kelantan and generally, in Malaysia. This process was culturally adapted and greater attention was given to food hawkers’ use of single-use plastic food containers in their business. Hence, this validated tool will be useful to assess the knowledge of other food hawkers around the country, in order to support the single-use plastics program in Malaysia. This can contribute to the reduction in environmental pollution from the excessive use of single-use plastics.
There are also limitations to this study, as it was confined to Kelantan state, representing only the north-eastern part of Malaysia. Cross validation of this study is suggested to involve other races and ethnicities in other part of Malaysia to improve the validity and reliability of this questionnaire. Moreover, the data collection was restricted due to the COVID-19 pandemic, and the use of single-use plastic food containers surged during this pandemic period.