1. Introduction
The prominence of LM as a systematic approach to eliminating waste and enhancing productivity in operations is increasingly recognized [
1,
2,
3]. Originating from the Toyota Production System, LM is a philosophy that has gained global adoption across various organizations, aiming to provide value to customers by reducing waste and optimizing efficiency [
4]. Previous research has demonstrated the direct impact of LM practices on operational performance metrics [
5], underlining the necessity for further empirical studies within the FP industry to explore these dynamics. LM principles in the FP industry primarily target the reduction in high food waste levels, which not only result in economic losses but also pose significant environmental concerns. Implementing LM can foster a culture of continuous improvement, reduce costs, enhance productivity, and improve customer satisfaction in the FP industry. This aligns with global initiatives for better planetary health by reducing waste and operating more efficiently in an environmentally responsible manner [
6,
7].
In Kosovo and North Macedonia, the FP industry is a key economic driver, significantly contributing to employment and GDP growth. Recently, there has been an increasing focus on adopting LM practices within the FP industry to boost operational efficiency and sustainability. By emphasizing waste reduction and continuous improvement, LM principles offer promising opportunities for optimizing processes and meeting the evolving demands of consumers in these regions. However, empirical studies specifically examining the impact of LM on operational performance metrics within the FP industries of Kosovo and North Macedonia are limited.
Despite extensive empirical evidence on the impact of LM on operational performance metrics across various industries, there is a notable gap in understanding its specific effects on the FP industries in Kosovo and North Macedonia. The existing literature lacks empirical studies that investigate the direct effects of LM practices on operational performance metrics within these regions. Thus, the first objective of this study is to examine how LM practices influence operational performance metrics in the FP industries of Kosovo and North Macedonia.
Furthermore, the existing literature underscores the importance of integrating LM principles with sustainability objectives in food production [
8,
9,
10,
11]. LM, with its focus on waste reduction and continuous improvement, closely aligns with sustainability goals, offering ways to minimize environmental impact and optimize resource use [
7,
12,
13]. Research has shown that LM practices can enhance environmental sustainability while also improving operational efficiency across various industries [
14]. However, there is a gap in empirical research addressing the integration of LM principles with sustainability objectives in food production within Kosovo and North Macedonia. By examining the integration of LM practices with sustainability goals, this study seeks to offer valuable insights into how organizations in Kosovo and North Macedonia can improve both operational efficiency and environmental sustainability. Consequently, the second objective of this research is to investigate the extent to which LM principles and sustainability objectives are integrated within the FP industries of Kosovo and North Macedonia.
While LM principles are known to significantly improve operational efficiency and reduce waste, their successful application must take specific contextual factors into account [
13,
15,
16]. Integrating sustainability objectives adds layers of complexity, as organizations must learn to balance economic viability with environmental and social responsibilities [
11,
14]. Implementing LM practices in the FP industry requires a nuanced understanding of cultural, regulatory, and infrastructural challenges that might hinder these efforts [
13]. It is also crucial to explore how LM principles can be leveraged to achieve better sustainability outcomes within the constraints of resources and market dynamics [
14]. While there is substantial global interest in analyzing the relationship of LM and sustainability, there are limited empirical studies addressing the particular challenges and opportunities of implementing these practices in the FP industries of Kosovo and North Macedonia. Understanding these challenges and opportunities is essential for FP companies in these regions. Hence, the third objective of this study is to identify the specific challenges and opportunities associated with the implementation of LM practices in the FP industries of Kosovo and North Macedonia.
2. Lean Manufacturing Principles and Their Application in the Food Processing Industry: A Comprehensive Review
Rooted in the Toyota Production System, LM principles have been broadly adopted by organizations to optimize their operations [
4]. At its core, LM strives to deliver customer value by reducing waste and improving efficiency [
17]. Womack and Jones (1996) [
18] identified five core principles of LM: identifying customer value; mapping the value stream; achieving continuous flow; implementing pull systems; and aiming for perfection. Many studies have established that LM practices contribute significantly to operational excellence through waste elimination and continuous improvement [
19,
20]. Shah and Ward (2007) [
4] proposed a model comprising ten elements of LM practices, encompassing supplier-related, customer-related, and internal aspects of operations. These elements include dimensions such as involved customers, supplier feedback, JIT delivery, supplier development, pull systems, flow optimization, setup time reduction, process control, productive maintenance, and employee involvement [
21,
22]. This model is notable for its comprehensive and balanced approach, addressing both the people and process aspects of LM [
23]. In this study, our primary focus will be on reviewing LM practices, as delineated in
Figure 1.
2.1. Supplier Engagement
In LM, supplier engagement entails having close collaboration with suppliers, offering performance feedback, and conducting reciprocal visits. This approach aims to establish long-term relationships with suppliers, integrating them into the production process to ensure the timely delivery of materials in the correct quantities [
22]. Effective supplier engagement fosters collaboration and enables a smooth flow of materials and information throughout the supply chain [
24]. Integrating LM with advanced technologies, such as Enterprise Resource Planning (ERP), Manufacturing Execution System (MES), and Radio Frequency Identification (RFID), can significantly enhance supply chain engagement and efficiency [
25,
26,
27]. Early supplier involvement is critical for successful product development within LM initiatives [
28]. However, in the FP industry, challenges like the seasonal availability and perishability of raw materials can impact JIT manufacturing practices [
15]. Consequently, extending LM practices beyond the firm’s boundaries in the FP industry may not always yield positive outcomes. This underscores the importance of understanding the industry context before LM integration [
21].
2.2. Customer Interaction and Feedback
Customer interaction in LM involves regularly engaging with customers to understand their needs, gathering quality and delivery feedback, sharing demand insights with the marketing department, and conducting satisfaction surveys for continuous improvement [
22]. The importance of engaging with customers throughout the product development process to deliver value-added solutions is crucial [
8,
29]. Integrating IT solutions like ERP and MES can improve responsiveness and customization, thereby enhancing customer involvement [
30]. In the FP industry, customer interaction and feedback are vital for meeting evolving consumer demands and ensuring product quality [
16]. LM practices in the FP industry result in reduced production costs, fewer customer complaints, increased profitability, and productivity [
23]. Furthermore, LM principles reduce production lead time, eliminate losses, and improve the utilization of space and machinery in FP companies [
31]. Adopting LM principles in FP companies also results in fewer product recalls, driven by quality and safety motivations [
23].
2.3. Pull System Implementation
The pull system in LM uses tools like Kanban to enable JIT production, signaling when to start or stop production based on the shipment of finished goods and current demand at the next station [
22]. Combining LM principles with technologies like Kanban further improves pull-based production systems [
32]. In continuous production environments such as the beverage industry, Kanban pull systems might be less feasible, making practices like TPM more critical [
33]. In the FP industry, production often involves batch or continuous processes, where the applicability of pull systems varies [
34]. While some studies report successful implementations of LM techniques like Value Stream Mapping (VSM) and 5S in large-scale food production settings, the effectiveness of pull production depends on factors like food safety requirements and work organization [
35]. Despite these challenges, pull systems are essential for minimizing waste and optimizing production processes in food manufacturing, along with other LM principles like leveled production and one-piece flow [
16].
2.4. Continuous Flow and Setup Time Reduction
Continuous flow (CF) in LM involves grouping products with similar processing requirements and arranging equipment to ensure an uninterrupted product flow. Setup time reduction (STR) focuses on minimizing downtime between product changeovers by practicing setups to reduce time requirements and working to lower setup times in plants [
22]. Both CF and STR are fundamental LM aspects aimed at minimizing waste and improving efficiency by ensuring smooth product flow and reducing setup times [
36]. LM tools such as VSM, TPM, JIT, Jidoka, and Heijunka can be implemented to reduce waste and improve flow [
37]. However, in the FP industry, implementing CF and STR practices presents challenges due to diverse product structures and necessary cleaning activities [
16,
38]. Frequent changeovers, driven by product variety, increase setup times, while strict cleaning requirements further complicate STR efforts [
15]. Despite these challenges, LM principles such as quick changeover and cellular manufacturing can enhance operational efficiency and reduce setup times in food manufacturing plants [
16].
2.5. Total Productive/Preventive Maintenance
TPM aims to minimize equipment downtime through planned maintenance activities, including regular maintenance, detailed record-keeping, and shared maintenance records on the shop floor [
22,
37]. TPM optimizes equipment efficiency, prevents breakdowns, and fosters operational autonomy by reshaping employee mindsets and engaging managers systematically [
39]. In modern industrial settings, where machine faults or suboptimal operation rates cause bottlenecks, compromised product quality, and order delays, TPM is crucial [
40]. Implementing TPM, coupled with digital technologies associated with Industry 4.0, enhances sustainable organizational performance [
8]. In food manufacturing, where equipment reliability and production integrity are paramount, TPM minimizes downtime and ensures smooth operations [
16]. Despite challenges like stringent hygiene standards, TPM remains vital to maintaining high production standards in food manufacturing plants [
15].
2.6. Statistical Process Control
SPC ensures defect-free processes by using statistical techniques to minimize process variance. SPC monitors stability and improves product quality while reducing waste and non-value-added activities [
22]. In various industries, including the electronics and electrical industries, SPC methods like Single Minute Exchange of Die (SMED) minimize setup times and enhance operational efficiency [
41]. Integrating SPC with Industry 4.0 technologies has been shown to improve operational performance [
36]. In the FP industry, characterized by high process variability, SPC is crucial for quality control and cost reduction. It aligns with food safety standards and integrates with systems like Hazard Analysis and Critical Control Point (HACCP), ensuring systematic food safety management [
15]. Despite challenges such as limited adoption, SPC methods are essential for consistently ensuring product quality and process efficiency in food manufacturing [
42].
2.7. Employee Involvement
Employee involvement in LM empowers shop floor employees to lead problem-solving teams, drive improvement efforts, manage suggestion programs, and undergo cross-functional training [
22]. LM promotes employee involvement in continuous improvement efforts, fostering a collaborative and innovative culture through practices like quality circles and team-based problem-solving [
24]. Control and human factors within LM emphasize the importance of employee involvement and empowerment in achieving quality goals and process improvement [
36]. LM practices support occupational safety and health through improved housekeeping, material handling, and workplace safety practices [
43]. Techniques like 5S, kaizen, and TPM improve equipment availability and quality while addressing challenges such as resistance to change. Top management commitment, training, and employee involvement are crucial for the success of LM initiatives [
23,
44]. In food manufacturing, employee involvement is critical for quality improvement and operational efficiency, relying on employee motivation, training, and participation to drive continuous improvement efforts [
16].
2.8. Zero Waste and Sustainability
ZW and sustainability in LM focus on minimizing waste generation and promoting sustainability through efficient resource utilization and waste reduction efforts [
13]. LM principles, such as waste elimination and continuous improvement, align with ZW and sustainability goals by optimizing processes and enhancing operational efficiency [
45]. According to Russell and Taylor (2008) [
46], LM is defined as any activity that consumes resources without adding value. These authors categorized waste into seven types: overproduction; waiting; transportation; unnecessary motion; inappropriate processing; and defects [
19]. Furthermore, they pointed out that underutilizing human potential due to restrictive management practices is a significant type of waste [
47]. However, strong management coaching can help effectively harness employee contributions [
45].
Another type of waste, referred to as “green waste”, pertains to the environmental impact caused by organizations. This includes greenhouse gas emissions, eutrophication, overuse of resources and energy, pollution, excessive generation of rubbish, high water consumption, and inadequate health and safety practices [
47]. Overuse of natural resources leads to environmental damage and resource depletion. Unlike customer-focused LM waste, green waste is viewed from an environmental perspective. Companies increasingly adopt sustainable approaches and initiatives to reduce all types of waste and align with global sustainability trends. Green manufacturing, which includes using renewable energy sources, is seen as an extension of LM, encouraging companies to reconsider their goals and strategies to prevent environmental burdens while satisfying customer needs [
6,
45]. LM companies implementing green practices achieve better results than those that do not consider sustainability [
47].
Lean sustainability contributes to a Circular Economy (CE), aiming for economic efficiency by maximizing resource utilization and minimizing environmental impact [
48,
49]. LM principles, including VSM and lean design, aim to minimize waste and maximize value across industries [
2]. Integrating LM practices with environmental management systems reduces costs and enhances sustainability [
11]. LM positively impacts economic, environmental, and social sustainability measures, contributing to overall sustainability goals [
14]. In terms of socio-economic and environmental sustainability, companies achieve efficiency by eliminating wastes, reducing costs, and improving efficiency through lean supply chain strategies [
43,
50].
In the FP industry, LM techniques reduce waste and enhance sustainability. Studies have identified waste areas in the food value chain and demonstrated how lean concepts like VSM can eliminate unnecessary inventories and waste, leading to cost reductions and increased customer satisfaction [
2,
13]. LM practices in FP focus on waste reduction, resource utilization improvement, and environmental protection, aligning with sustainability goals [
49]. Nevertheless, resistance to change and limited adoption of LM techniques remain significant barriers to achieving sustainable outcomes in the FP industry [
13].
2.9. The State of Lean Manufacturing Practices in the Food Processing Industries in Kosovo and North Macedonia
Despite extensive evidence of LM benefits for ZW and sustainability in various industries, research on its application in Kosovo and North Macedonia’s FP industry is limited. Key gaps include the need to study the direct effects of LM practices on operational performance and their integration with sustainability goals in the food processing industry. Additionally, there is a lack of empirical studies on the unique challenges and opportunities of LM implementation in these regions, such as organizational resistance and resource constraints. Addressing these gaps through research is essential for understanding LM’s role in enhancing sustainability and operational excellence in Kosovo and North Macedonia’s FP industries.
To address these gaps, the following research questions have been formulated to guide this study:
How do LM practices directly impact operational performance metrics in Kosovo and North Macedonia’s FP industries?
To what extent are LM principles integrated with sustainability objectives in food production in these regions?
Considering factors like organizational resistance and resource constraints, what specific challenges and opportunities are associated with LM implementation in Kosovo and North Macedonia’s FP industries?
These questions will help explore the role of LM in promoting sustainability and operational excellence in the FP industries of Kosovo and North Macedonia.
3. Methodology
To evaluate the impact of LM practices on operational performance, the integration of LM principles with sustainability goals, and the challenges and opportunities in the FP industries of Kosovo and North Macedonia, this study employed a qualitative multiple case study approach. The use of multiple cases aims to deepen the understanding of the phenomena under investigation and enhance the generalizability of the findings.
This research involved nine case studies in total, comprising four food manufacturing companies from Kosovo and five from North Macedonia. The selected companies varied in size, workforce, and product range, ensuring a diverse representation of the FP industries. These companies produced a wide range of food products, including dietary supplements, organic foods, premixes, baked goods, dairy products, beverages, and snacks. An overview of the case studies is provided in
Table 1.
Before visiting each company, a list of questions was sent to the personnel to help them prepare their responses. Each company visit was meticulously planned, combining interviews with physical tours of the facilities. The semi-structured interviews typically lasted at least two hours. At the start of each interview, the research objectives as well as an overview of the LM framework were introduced. The interviews focused on topics such as the company’s products, market, raw materials, and processes. Within these topics, various issues were discussed to gather participants’ views. Interviewees included plant managers, purchasing managers, and operations managers. Interviews were recorded using an audio recording device. This approach was communicated to the participants beforehand, and permission to use the recording equipment was granted.
The interview guide was developed from a thorough literature review to facilitate discussions and uncover the impact of LM practices on operational performance and their integration with ZW technologies and sustainability. This guide comprised nine main themes, designed to capture insights relevant to each company’s context.
Table 2 presents the interview themes and the supporting literature.
To analyze the qualitative data, this study employed Miles and Huberman’s (1994) thematic analysis approach, which involved a multi-step coding process [
63]. The first step involved transcribing the audio-recorded interviews using Otter AI software (Version 3.54.0.240708—de94a87d319953f9e6a9a58942237bd2a1883e92). These transcriptions provided a written record of the interviews, capturing every detail of the discussions with the participants. The transcribed interviews were then thoroughly reviewed to ensure accuracy, correcting any errors and making sure the transcripts accurately represented the spoken words. Once the transcripts were finalized, they were imported into NVivo software (NVivo 14—Windows Trial—Subscription number: A-S00411317). Each transcript was imported as a separate document within NVivo, and demographic information about the interviewees and their respective companies was also added to the dataset for context.
The analysis began with an open coding process, where the transcripts were read thoroughly and initial codes were assigned to segments of text that were relevant to the research questions. These codes were based on the themes identified in the literature review and the interview guide. NVivo facilitated this process by allowing the creation of codes that represented different themes or concepts. Each relevant segment of text was linked to these codes. After the initial coding, the codes were reviewed and refined. Similar codes were grouped together to form broader themes, and any redundant or overlapping codes were merged. This step involved a more detailed and iterative coding process, where themes were continuously refined and organized hierarchically within NVivo to reflect the underlying structure of the data.
With the themes established, the next step was to explore and analyze the data within each theme. Thematic analysis was conducted to understand how different themes related to each other and to the overall research questions. This included examining the context in which certain themes emerged and how they were discussed by different interviewees. The thematic analysis framework is depicted in
Figure 2.
To substantiate the findings, relevant quotes from the interview transcripts were identified and extracted. These quotes illustrate key points and provide evidence for the themes and conclusions drawn from the analysis.
The final step involved compiling the results into a coherent narrative. The themes and supporting quotes were organized to address the research questions and objectives. The results are presented in a structured manner in the next section, with each theme discussed in detail and contextualized within the broader literature on LM practices and sustainability.
4. Results and Discussion
4.1. Supplier Engagement
Analyzing the interview transcripts from the nine case studies provided significant insights into supplier engagement practices, highlighting coordination for JIT delivery, contractual commitments for cost reductions, communication frequency, feedback mechanisms, and measures to establish long-term relationships. These findings align with the existing literature on LM, which emphasizes supplier integration and collaboration [
22,
24].
Several companies highlighted the importance of close collaborations with suppliers to ensure JIT delivery of raw materials. For example, the operations manager from case study 1 stated, “
We have established a close working relationship with our key suppliers to ensure they understand our production schedule and can deliver raw materials on a JIT basis”. Similarly, the development and innovation manager from case study 6 noted the importance of frequent communication with suppliers, as well as timely planning and notification to suppliers of planned required raw materials. These practices exemplify LM’s emphasis on supplier collaboration to enhance operational efficiency [
25,
26].
The use of formal contractual arrangements with suppliers to secure annual cost reductions was also highlighted. These contracts include specific targets and objectives for cost reduction, with incentives or penalties based on performance. The production director from case study 2 mentioned, “We have contracts with each supplier that clearly stipulate penalties in case of non-compliance. We work with our suppliers to identify areas where we can collaborate on cost savings”. Similarly, the business development and operations manager from case study 4 stated, “To secure annual cost reductions from our key suppliers, we establish formal contracts that outline the terms and conditions of our partnership”.
Regular communication with suppliers is crucial for smooth supply chain operations. Companies maintain frequent contact with suppliers, adapting their communication frequency based on operational needs. The production manager from case study 3 noted, “We maintain regular contact with our suppliers to ensure timely delivery of materials and address any immediate concerns or issues that may arise”. The operations manager/technologist from case study 7 added, “Regular communication with suppliers is essential for our operations”.
Feedback on quality and delivery performance is critical for effective supplier engagement. Companies use various channels, including meetings, emails, phone calls, and audits, to provide feedback. The production manager from case study 3 stated, “
We provide feedback to our suppliers through various channels. One of the common ways is through phone conversations,
where we can directly discuss any concerns or issues regarding quality or delivery performance”. Additionally, the managing director from case study 5 mentioned, “
We exchange questionnaires for satisfaction and organize audits of our supplier every three years”. These practices align with the LM principles of continuous improvement and supplier involvement [
28,
36].
Building long-term relationships with suppliers involves open communication, collaborative problem-solving, and a shared commitment to quality and efficiency. The director of commerce from case study 8 highlighted, “
By working closely and finding solutions together,
we nurture relationships that are built on trust and reliability”. The production manager from case study 9 similarly emphasized, “
Long-term relationships with suppliers are fostered through effective communication,
collaborative problem-solving,
and a shared commitment to quality and efficiency”. This underscores the importance of supplier engagement in supporting LM practices effectively [
22,
27].
However, challenges specific to the FP industry, such as seasonal availability and perishability of raw materials, may impact the implementation of LM practices related to JIT manufacturing [
15,
21]. Addressing these challenges is crucial for advancing LM in the FP industry, particularly in Kosovo and North Macedonia.
4.2. Customer Interaction and Feedback
The case studies revealed various strategies employed by companies to interact with customers and incorporate their feedback into operations, aligning with LM practices that emphasize customer engagement [
22,
29]. All interviewed companies prioritize understanding and meeting customer needs. For instance, case study 1 regularly gathers customer feedback through surveys, focus groups, and direct communication channels: “
Our company is deeply committed to understanding and fulfilling the needs of our customers”. Similarly, case study 3 highlights conducting market research and surveys to gather insights into customer preferences and expectations: “
Our company is highly dedicated to prioritizing our customers and addressing their needs”.
Customers provide valuable feedback on the quality and delivery performance of products, enabling companies to rectify issues promptly and improve operations, reflecting the LM principles of continuous improvement and customer involvement [
8]. In case study 4, customers actively alert the company about quality issues, helping maintain high standards: “
Our customers play an active role in providing feedback,
particularly concerning the quality and delivery performance of our products”. This perspective is also reflected in case study 7: “
Our customers provide feedback on the quality and delivery performance of our products”.
Several companies involve customers directly in product development. For example, case study 2 conducts product testing sessions with customers to gather feedback on new products before release. Similarly, in case study 8, customers’ insights and preferences shape product strategies, ensuring that the offerings resonate with their tastes. This direct involvement underscores the value of integrating customer feedback into the product development process, which is a core tenet of LM [
16,
22].
Customer feedback is primarily conveyed through marketing departments across most case studies, although communication channels vary. In case study 6, information is primarily communicated through the marketing department, while in case study 9, it is conveyed via email or meetings involving both the marketing department and the production manager. The frequency of customer satisfaction surveys also varies. While some companies conduct surveys once or twice a year, others rely on continuous feedback mechanisms. For instance, in case study 7, surveys are conducted annually to gauge customer satisfaction and gather insights for improvement.
These practices reflect the flexibility of LM approaches to adapt to different organizational contexts and customer preferences [
30]. The emphasis on customer interaction and feedback in the FP industry aligns with the industry’s dynamic nature, where meeting consumer demands and ensuring product quality is critical for success [
16,
23].
4.3. Pull System Implementation
The exploration of pull system implementation across the nine case studies revealed diverse approaches and practices. Some companies had fully embraced JIT practices, while others were still transitioning. For instance, the production manager from case study 3 acknowledged awareness of JIT concepts but noted incomplete integration: “Our company is aware of JIT concepts but has not yet fully integrated them into our operations”. In contrast, case study 8 had established JIT production, with technologists and shift leaders signaling production start and stop times.
The tools used for signaling within pull systems varied widely. Some companies relied on sophisticated tools such as visual management, Kanban, and ERP systems to track production status, inventory levels, and key performance indicators. For instance, the operations manager from case study 1 noted, “We use visual management and ERP systems extensively to keep track of our production status and inventory levels”. Similarly, the managing director from case study 5 stated, “Kanban cards and our ERP system are integral to our production process, helping us monitor key performance indicators effectively”. Others employed simpler methods like pull systems and alarms to signal production milestones and interruptions. The production director from case study 2 mentioned, “We use basic pull systems and alarms to signal different stages of production and any interruptions”. Likewise, the development and innovation manager from case study 6 explained, “Our signaling method is straightforward; we rely on pull systems and audible alarms to manage production flow”. Despite the tool differences, the consistent goal was to optimize production processes, minimize waste, and enhance responsiveness to customer demand. The production manager from case study 3 emphasized the fact that “Regardless of the tools we use, our focus is always on optimizing production and minimizing waste”.
Customization and flexibility were prominent themes, with companies adapting their production processes to their specific needs and circumstances. For example, the production director from case study 2 highlighted, “
We meticulously plan our production schedules well in advance to ensure a smooth workflow and minimize disruptions”. This approach illustrates the adaptability required to meet specific operational demands. The variability in adopting pull systems reflects differing organizational contexts [
22]. The range of signaling approaches, from sophisticated tools to simpler methods, underscores the flexibility of pull-based production systems and the importance of aligning production processes with actual customer demand [
32]. Despite the tool differences, the overarching goal across the case studies remained consistent: optimizing production processes, minimizing waste, and enhancing responsiveness to customer demand.
The adaptation of production processes to suit specific needs aligns with the LM principles of continuous improvement and adaptation [
1]. However, the applicability of pull systems may vary depending on the production environment. In continuous production settings like the beverage industry, challenges may arise due to factors like food safety requirements and work organization [
33]. In the FP industries of Kosovo and North Macedonia, implementing pull systems can be challenging, yet they remain crucial for minimizing waste and optimizing production processes, along with other LM principles like leveled production and one-piece flow [
16].
4.4. Continuous Flow and Setup Time Reduction
The interviews from various case studies revealed several key insights about CF and STR. Implementing mechanisms to facilitate CF is common practice among the participants. These mechanisms often include systems like Kanban, standardized work processes, visual management tools, and dedicated software to track demand patterns and streamline production processes. For example, the operations manager from case study 1 emphasized the importance of the Kanban system, stating, “
Yes,
we have implemented several mechanisms to enable and ease the CF of products in our company. As mentioned before,
one of the key mechanisms we have established is the implementation of the Kanban system”. This aligns with LM principles, which emphasize optimizing production processes and minimizing waste through CF mechanisms [
22].
Another common practice is the classification of products into groups with similar processing or routing requirements. Grouping products based on these similarities aims to reduce setup times, minimize disruptions, and optimize production flow. This classification helps in organizing production lines more effectively, facilitating a smoother production flow, and enhancing overall productivity. The production director from case study 2 confirmed this, stating, “Yes, grouping products with similar processing or routing requirements is an important aspect of LM in our company”. However, not all companies have established mechanisms for CF or product classification to the same extent. Some interviewees mentioned limitations in their current capabilities or practices, indicating ongoing efforts to improve and optimize their processes within existing constraints. The development and innovation manager from case study 6 admitted, “We have not established mechanisms in our company that enable and facilitate the CF of products”.
Employee training and flexibility also play crucial roles in achieving CF and STR. In case study 9, the emphasis on cross-training employees ensures that staff can work in various positions as needed, enhancing the overall flexibility and responsiveness of the production process. The production manager from case study 9 highlighted that “
It is important that all employees are trained to be able to work at any given position”. This underscores the importance of human resources in LM initiatives and the critical role of employee adaptability [
37].
However, challenges such as power outages and unforeseen events can disrupt efforts to maintain CF, emphasizing the need for resilience and adaptation in LM practices. The production director from case study 2 mentioned, “
The power outage also causes problems in the sensors which means that the machine needs to be completely reset”. This demonstrates the importance of building robust systems that can quickly recover from disruptions [
38].
Overall, while the case studies show common employment of mechanisms like Kanban systems, standardized work processes, and product grouping to facilitate CF and reduce setup times, not all companies have fully implemented these mechanisms. These findings underscore the importance of continuous improvement and adaptation in LM practices to optimize production processes, minimize waste, and enhance overall productivity, aligning with the broader goals of LM principles. This is especially pertinent in the context of the FP industries of Kosovo and North Macedonia, where unique challenges may arise in implementing these practices.
4.5. Total Productive/Preventive Maintenance
The importance of TPM in achieving high equipment availability and minimizing unplanned downtime was emphasized by the companies. For example, case study 1 highlighted the implementation of TPM to ensure equipment availability through preventive maintenance, employee involvement, and a sense of ownership: “Yes, our company implements TPM to ensure the high availability of equipment and minimize unplanned downtime”. Similarly, case study 3 emphasized the importance of proactive maintenance practices and involving all employees in the maintenance process to promote equipment reliability: “We recognize the importance of proactive maintenance practices in maximizing equipment uptime and minimizing unplanned downtime”. Case study 8 also prioritized preventive maintenance to ensure optimal equipment performance.
Regarding the management of facility and equipment maintenance, various approaches were observed. Some companies utilize specialized software such as the Computerized Maintenance Management System (CMMS) or Enterprise Asset Management (EAM) software (case study 1), while others rely on manual methods such as maintenance plans crafted by machine vendors (case study 2). “As for equipment maintenance, we work according to the recommendations of Tetra Pak, that is, the manufacturer of those devices”. Some companies also use Excel files for tracking maintenance activities (case study 9). Despite the absence of specialized software in certain cases, companies actively explore future implementation to enhance maintenance processes (case study 3).
Sharing equipment maintenance records with frontline employees was addressed differently across companies. Some companies, such as those in case studies 1, 2, 6, and 9, use bulletin boards on the shop floor to post maintenance records, ensuring easy access for employees. As expressed by the operations manager from case study 1, “We post maintenance records on bulletin boards in the production area so that everyone can see the status and schedule of equipment maintenance”. Similarly, in case study 2, maintenance records are made available on bulletin boards around the shop floor to ensure all employees can access the information easily. In contrast, companies like the one in case study 7 employ manual distribution and training sessions to ensure effective communication of maintenance records within the team: “We distribute maintenance records manually and conduct training sessions to make sure all team members are aware of the maintenance status and procedures”. Additionally, in case studies 8 and 9, regular meetings and yearly maintenance plans are utilized to share maintenance-related information with employees. The director of commerce from case study 8 mentioned, “We conduct frequent meetings to discuss maintenance issues and communicate yearly maintenance plans with our employees to keep everyone informed and aligned”. Similarly, in case study 9, regular meetings and yearly maintenance plans are shared with the team to ensure everyone is updated on maintenance activities and can plan accordingly.
Regarding TPM, companies prioritize preventive maintenance practices to promote equipment reliability and maximize uptime [
22]. By involving all employees in the maintenance process, companies foster a sense of ownership and accountability, contributing to overall equipment performance [
39]. Various approaches to facility and equipment maintenance management were observed, including the use of specialized software like CMMS and manual methods such as maintenance plans crafted by machine vendors. Despite differences in approaches, companies actively explore future implementations, reflecting a shared commitment to enhance maintenance processes over time [
8]. Sharing maintenance records with frontline employees through bulletin boards and conducting regular training sessions and meetings enhances communication and ensures the effective dissemination of maintenance-related information within the team [
15]. In the context of the FP industries of Kosovo and North Macedonia, where equipment reliability is critical, TPM plays a vital role in minimizing downtime and maintaining high standards of production integrity, despite challenges such as stringent hygiene standards and cleaning requirements.
4.6. Statistical Process Control
Based on the data from the interviews, it is evident that companies employ various strategies to ensure that each process delivers defect-free units to subsequent processes through SPC. One approach commonly mentioned across the interviews involves the implementation of SPC tools and techniques to monitor processes and identify variations that may lead to defects. This includes the use of control charts, histograms, and Pareto charts to track process performance and analyze data (case study 1). Additionally, regular data collection and analysis are conducted to monitor key process parameters and quality characteristics, with control charts used to detect deviations and take corrective actions promptly (case study 3).
Furthermore, companies emphasize the importance of quality control measures and inspections throughout the production process. This includes robust inspection and testing procedures at various stages, conducted by trained quality control personnel (case study 2). Additionally, rigorous quality control activities involving measurements and monitoring are implemented to maintain high product quality (case study 7). Some companies prioritize minimizing defects through stringent quality checks and continuous monitoring, even if formal SPC methods are not implemented (case study 8). Similarly, constant control and monitoring of processes are highlighted as key strategies to ensure defect-free units (case study 6). Moreover, companies leverage data analysis and reporting mechanisms to track process performance and identify deviations. For instance, case study 2 utilizes a dashboard with daily, weekly, and annual data to monitor waste and damage, triggering alerts when tolerable waste levels are exceeded. Case study 5 conducts yearly management reviews with trending results to ensure quality standards are met. Overall, while specific approaches may vary, the common goal across all companies is to maintain high-quality standards through effective SPC practices, rigorous quality control measures, and continuous monitoring of processes.
The findings regarding SPC underscore its importance in ensuring defect-free processes and maintaining high-quality standards, aligning with the principles outlined in the literature on LM. Companies employ various SPC tools and techniques, such as control charts and histograms, to monitor processes, detect variations, and take corrective actions promptly, aiming to minimize process variance and improve product quality [
22]. Quality control measures and inspections are emphasized throughout the production process, with rigorous inspection and testing procedures conducted at various stages by trained quality control personnel. While specific approaches may vary, the overarching goal is to maintain high-quality standards through effective SPC practices and continuous monitoring of processes [
41]. SPC plays a crucial role in the context of the FP industries of Kosovo and North Macedonia, where it ensures compliance with food safety standards and integrates with systems like HACCP to ensure systematic food safety management. Despite challenges, SPC methods are essential for consistently ensuring product quality and process efficiency for the FP companies in Kosovo and North Macedonia, aligning with the principles of LM and contributing to waste reduction and cost optimization [
15].
4.7. Employee Involvement
Data from interviews across various case studies highlight the critical role of employee engagement in organizational success and continuous improvement. Companies recognize the value of empowering employees to propose ideas and solutions for enhancing processes and operations. This empowerment fosters a sense of ownership and accountability among employees, thereby increasing engagement and innovation. For instance, the operations manager from case study 1 stated, “We empower our employees to identify and implement improvements in our processes. This sense of ownership motivates them to actively participate in our continuous improvement initiatives”.
In addition, companies prioritize transparent communication about organizational goals, performance metrics, and improvement initiatives. They use regular meetings, newsletters, and digital communication platforms to facilitate open dialogue between management and employees. As the managing director from case study 5 noted, “We have regular meetings to discuss our progress, challenges, and ideas for improvement. This open communication fosters collaboration and engagement among our team members”. Companies also emphasize the importance of investing in employee training and development to enhance skills, knowledge, and capabilities. They provide opportunities for ongoing learning and skill enhancement to ensure employees are well-equipped to perform their roles effectively. Training programs cover various areas, including technical skills, problem-solving methodologies, and safety protocols, as noted in case studies 2, 3, and 8. Furthermore, companies implement recognition programs to acknowledge exceptional performance, innovative ideas, and commitment to organizational goals. Recognition can take various forms, including verbal praise, awards, incentives, and career advancement opportunities. The development and innovation manager from case study 6 mentioned, “We have a recognition program in place to celebrate the achievements of our employees. This recognition boosts morale and encourages others to strive for excellence”.
Overall, our results highlight the importance of employee engagement in driving organizational success and continuous improvement. By empowering employees, fostering open communication, providing training opportunities, and recognizing contributions, companies create a culture of engagement and innovation that enhances productivity, morale, and overall performance. These results underscore the critical role of employee involvement in organizational success and continuous improvement, in line with LM principles. The case studies emphasize the necessity of empowering employees to contribute ideas and solutions, which nurtures a sense of ownership and accountability, thereby motivating active involvement in improvement initiatives [
22]. Clear communication regarding organizational goals, performance metrics, and improvement initiatives promotes open dialogue between management and staff, enhancing collaboration and engagement [
24]. Furthermore, investing in employee training and development is vital for enhancing skills and knowledge, ensuring that employees are well-prepared to perform their roles effectively [
36]. Recognition programs that highlight exceptional performance and contributions serve to boost morale and inspire others to strive for excellence [
23].
4.8. Zero Waste and Sustainability
ZW and sustainability were explored in various case studies, focusing on waste reduction strategies, the utilization of byproducts/waste, awareness of penalties related to waste, and alignment with global sustainable initiatives. During the interviews, participants detailed their efforts to minimize waste generation through different strategies. Some highlighted the implementation of LM principles, optimization of production planning, and the use of efficient packaging materials to reduce waste, as seen in case study 1. Others discussed collaborations with external partners for waste disposal and recycling initiatives. For instance, case study 2 mentioned, “The disposal process for juice packaging is complex due to its multilayered structure, requiring sophisticated recycling equipment to separate the layers of polyethylene, cardboard, aluminum, etc.”.
Regarding the utilization of byproducts and waste, participants mentioned recycling programs, partnerships with external entities, and responsible waste management practices, as noted in case studies 1 and 2. However, some participants admitted they have not fully optimized waste disposal practices or established proper recycling mechanisms, as observed in case study 3. Participants also discussed their awareness of penalties related to waste and compliance with waste management regulations. They mentioned adherence to regulatory requirements and investments in environmental initiatives such as wastewater treatment plants. Case study 7 highlighted, “While achieving ZW is challenging, we strive to optimize waste to minimize costs and comply with our country’s waste management laws”. Furthermore, participants revealed diverse levels of engagement with global sustainability initiatives. In particular, some companies have actively embraced and aligned their operations with frameworks like the United Nations Sustainable Development Goals (SDGs) and the EU Green Deal, as highlighted in case studies 4 and 8. Other companies recognized the significance of these global sustainability trends but did not elaborate on their specific alignment efforts, as seen in case study 6.
The findings indicate a strong dedication among companies to reduce waste and promote sustainability through various strategies, aligning with the principles highlighted in the literature on ZW and sustainability. LM principles, such as waste elimination and continuous improvement, support ZW and sustainability objectives by optimizing processes and enhancing operational efficiency [
45]. Waste reduction strategies include the adoption of LM principles, the optimization of production planning, and the use of efficient packaging materials [
18]. Collaboration with external partners for waste disposal and recycling initiatives is also emphasized [
13]. Some companies are especially focused on the utilization of byproducts and waste through recycling programs and responsible waste management practices [
45]. However, some companies are still in the process of fully optimizing their waste disposal practices. Furthermore, the extent to which companies align with global sustainability initiatives varies, with some actively considering and incorporating initiatives such as the SDGs and the EU Green Deal into their operations [
11]. Integrating LM practices with environmental management systems not only reduces costs but also improves sustainability [
11].
4.9. The Impact of LM on ZW Technologies
The interview data revealed that LM significantly influences the advancement of ZW technologies. Participants underscored how LM principles, such as waste elimination, process streamlining, and resource optimization, are crucial in achieving ZW goals. They stressed that incorporating LM practices into daily operations fosters a culture of waste reduction, continuous improvement, and sustainability, which enhances overall efficiency and environmental responsibility (case study 1). Furthermore, the importance of LM principles in reducing waste and improving efficiency was a recurring theme. Although not always explicitly termed JIT, companies consistently focus on enhancing efficiency and minimizing waste through streamlined processes and reduced delays. This emphasis on collaboration and innovation among team members is vital in their pursuit of achieving “golden zero” waste (case study 2). The interviews also highlighted the shared objectives of waste minimization and operational optimization between the JIT and ZW initiatives. While fully implementing JIT production is still a work in progress for many, companies are actively identifying waste generation points and deploying strategies to reduce waste across the entire value chain (case study 3). Lastly, participants reiterated the positive impact of LM on ZW technologies. They noted that lean’s core principle of waste reduction aligns perfectly with ZW production goals. The systematic and continuous improvement aspects of LM are seen as key drivers in promoting sustainable and environmentally friendly practices within the FP industry (case studies 4, 7, and 9).
These findings, situated within the context of the literature review on ZW and sustainability, confirm the alignment of LM principles with ZW and sustainability objectives. LM principles such as waste elimination and continuous improvement are essential for optimizing processes and improving operational efficiency, thus supporting ZW and sustainability goals [
45]. Companies are increasingly adopting sustainable practices and initiatives to minimize all forms of waste, aligning with global sustainability trends by integrating LM practices [
45]. Lean sustainability further contributes to a circular economy by maximizing resource utilization and minimizing environmental impact, underscoring the critical role of LM principles in advancing ZW [
48,
49]. Moreover, the integration of LM with ZW technologies not only enhances operational efficiency but also promotes sustainability and environmental stewardship within the FP industry.
6. Conclusions
This study set out to explore the influence of LM practices on operational performance, the integration of LM principles with sustainability goals, and the specific challenges and opportunities tied to LM implementation within the FP industries of Kosovo and North Macedonia. The first objective was to understand how LM practices affect operational performance metrics in these regions. The analysis showed that LM practices such as JIT, TPM, SPC, and employee involvement significantly enhance operational performance metrics, including efficiency, quality, and responsiveness. The second objective was to examine how LM principles align with sustainability objectives within the FP industry. Our findings indicate a strong alignment, particularly in areas such as waste reduction, resource optimization, and environmental responsibility. This demonstrates the potential of LM practices to support sustainable food production. The third objective was to identify the challenges and opportunities associated with implementing LM practices in the FP industries of Kosovo and North Macedonia. The analysis revealed several challenges, such as organizational resistance, resource constraints, and unique contextual factors. Nevertheless, opportunities for improvement were also identified, particularly through employee involvement, supplier engagement, and continuous improvement initiatives.
This study contributes to the understanding of LM practices in the FP industries of Kosovo and North Macedonia, highlighting their potential to enhance operational performance and promote sustainability. By effectively leveraging LM principles, organizations can improve efficiency, reduce waste, and move towards more sustainable food production practices. The findings underscore the theoretical implications of LM practices in enhancing operational efficiency, reducing waste, and promoting sustainability in the FP industry. The integration of LM principles with sustainability objectives underscores the relevance and applicability of LM principles in addressing contemporary challenges in food production. Moreover, it is evident that LM practices have practical implications for improving operational performance, minimizing waste, and promoting sustainability in these regions. Practical recommendations include implementing JIT, TPM, and SPC and fostering employee involvement to overcome challenges and capitalize on opportunities for improvement.
While this study offers valuable insights, it is important to acknowledge its limitations. The focus was limited to LM practices within the FP industries of Kosovo and North Macedonia. Future research could expand to other industries or regions. Additionally, this study relied on qualitative data, and incorporating quantitative analysis could provide deeper insights into the impact of LM practices. Furthermore, longitudinal studies could help assess the long-term effects of LM implementation on operational performance and sustainability metrics.