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Chemical Engineering & Development

Journal of Science and Engineering

Vol. 08 / Nº 01

e – ISSN: 3028-8533

ISSN – L: 3028-8533

Chemical Engineering & Development

University of Guayaquil | Faculty of Chemical Engineering

Guayaquil – Ecuador

https://revistas.ug.edu.ec/index.php/iqd

Email: inquide@ug.edu.ec

francisco.duquea@ug.edu.ec

Pag. 29

Assessment of occupational risks in the Ecuadorian dairy industry.

Valoración de los riesgos ocupacionales en la industria láctea ecuatoriana.

Mayerli Angeline Mejía Monar

; Carlos Alberto Velásquez Avilés

& Ivan Patricio Viteri García

Received: 06/26/2025 – Accepted: 08/19/2025 – Published: 01/01/2026

Research

Articles

Review

Articles

Essay Articles

* Corresponding

author.

This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 (CC BY-

NC-SA 4.0) international license. Authors retain the rights to their articles and may share, copy, distribute,

perform, and publicly communicate the work, provided that the authorship is acknowledged, not used for

commercial purposes, and the same license is maintained in derivative works.

Summary.

This review examines sixty publications (2013-2025) to assess how occupational risks are prevented within dairy plants, with emphasis on Latin American

and, in particular, Ecuadorian experiences. The analysis is structured around five lines of action: (i) Good Manufacturing Practices combined with the 5S

methodology; (ii) participatory ergonomics aimed at redesigning tasks; (iii) digital lockout-tagout linked to predictive maintenance; (iv) chemical controls

based on ventilated cabinets and ammonia sensors, and (v) ISO 45001–ISO 22000 integrated management systems. On average, these measures reduce

the accident rate by between 22% and 36%, which supports the idea that the overlapping of technical and organisational barriers increases protection.

However, most studies offer brief follow-ups and use diverse metrics, so longitudinal work and unified measurement frameworks are advised to confirm

the sustainability of the benefits.

Keywords.

occupational dairy safety; BPM; 5S; participatory ergonomics; digital lockout-tagout; predictive maintenance; chemical management; ISO 45001; ISO

22000.

Abstract.

This review draws on sixty sources published between 2013 and 2025 to assess how dairy plants manage occupational hazards, paying special attention

to Latin American—and especially Ecuadorian—settings. Five intervention strands are discussed: (i) Good Manufacturing Practices coupled with the 5S

method; (ii) participatory ergonomics aimed at task redesign; (iii) digital lockout-tagout paired with predictive maintenance; (iv) chemical controls

through ventilated cabinets and ammonia sensors; and (v) integrated ISO 45001–ISO 22000 management systems. On average, these strategies cut

accident rates by 22 % to 36 %, lending weight to the notion that layered technical and organisational barriers enhance safety. Yet most studies track

outcomes for only short periods and rely on non-standard metrics, highlighting the need for longer follow-ups and harmonised measurement frameworks

to judge long-term effectiveness.

Keywords.

Dairy occupational safety; Good Manufacturing Practices; 5S; participatory ergonomics; digital lockout-tagout; predictive maintenance; chemical

management; ISO 45001; ISO 22000.

1. Introduction

1.1.- Occupational risks in the dairy industry

The dairy industry plays a strategic role in the economies of

many regions, including Ecuador, through the

transformation of raw milk into derivatives (cheeses,

yogurts, powdered milk) and the generation of direct

employment in processing plants and in the primary sector.

However, this production chain involves mechanical

(rotating equipment, packaging lines), ergonomic (manual

handling of loads, forced postures), chemical

(alkaline/acidic solutions in CIP, ammonia in refrigeration),

physical (noise, vibrations, heat stress) and biological

(exposure to zoonoses in milking). Numerous studies

indicate that the accident rate in dairy plants is relatively

high compared to other food subsectors [1, 3, 4].

Despite documented interventions in European and North

American contexts, there is a gap in evidence on

implementation and effectiveness in SMEs and in Latin

Technical University of Babahoyo; mmejiam@faciag.utb.edu.ec; https://orcid.org/0009-0003-9849-2102, Babahoyo; Ecuador.

Technical University of Babahoyo; cvelasquez904@faciag.utb.edu.ec; https://orcid.org/0009-0006-5593-6641, Babahoyo; Ecuador.

University of Guayaquil; ivan.viteriga@ug.edu.ec ; https://orcid.org/0000-0003-0522-3302, Guayaquil; Ecuador.

American settings, particularly in Ecuador. In addition, the

heterogeneity of the metrics employed (accidents per

million man-hours, RULA/REBA scores, MTBF, ammonia

ppm levels, safety climate scores) makes it difficult to

compare results and draw global conclusions [16, 49, 50].

Therefore, it is essential to review in an integrated way the

prevention strategies used, their effectiveness and

adaptability to the context of the Ecuadorian dairy industry.

The dairy industry presents a unique combination of risks

arising from the interaction between manual and automated

processes. Milking, pasteurization, packaging, and clean-in-

place (CIP) operations expose workers to mechanical

hazards such as entrapment in rotating equipment, as well

as chemical hazards from the use of caustic solutions and

coolants such as ammonia. Added to this are physical

factors – noise, vibrations and thermal stress in refrigeration

chambers – and biological factors, linked to the handling of

raw milk and the possible transmission of zoonoses. This

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e – ISSN: 3028-8533

ISSN – L: 3028-8533

Chemical Engineering & Development

University of Guayaquil | Faculty of Chemical Engineering

Guayaquil – Ecuador

https://revistas.ug.edu.ec/index.php/iqd

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Pag. 30

diversity of risks requires a comprehensive preventive

approach that includes technical, organizational and cultural

controls [41].

In the Ecuadorian context, the situation is aggravated by the

predominance of small and medium-sized plants with

technological and budgetary limitations. Local studies show

that the lack of standardized protocols and poor training

increase the frequency of accidents, especially in cleaning

and maintenance tasks. In addition, staff turnover and labor

informality make it difficult to consolidate a preventive

culture. Therefore, the identification and prioritization of

critical risks – ergonomic, chemical and mechanical –

becomes an essential starting point for designing strategies

adapted to the reality of dairy SMEs [42].

1.2.- Theoretical models of safety (Reason, NIOSH)

Safety in the dairy industry is best approached from a

systemic perspective, where the interaction between human,

technical, and organizational components defines global

resilience [1]. Reason's model explains that accidents arise

from the alignment of latent and active faults; therefore, it

is crucial to overlap control barriers [3]. The NIOSH

hierarchy of controls prioritizes eliminating or substituting

hazards (e.g., replacing caustic alkalis with enzymatic

detergents or implementing closed systems) rather than

relying on PPE exclusively [4, 28, 30].

The "Swiss cheese" model proposed by Reason is a

fundamental reference for understanding the genesis of

accidents in complex systems. According to this approach,

incidents occur when latent failures (organizational

deficiencies, lack of maintenance) align with active failures

(human error, unsafe conditions), breaking through defense

barriers. In the dairy industry, these barriers include

lockout/tagout protocols, ventilation systems, and staff

training. The absence or weakness of a single layer

exponentially increases the probability of serious accidents

[10].

Meanwhile, the NIOSH hierarchy of controls establishes a

logical sequence for risk mitigation: disposal, replacement,

engineering controls, administrative controls, and personal

protective equipment (PPE). Applied to the dairy sector, this

hierarchy involves prioritizing the substitution of caustic

products with enzymatic detergents, implementing

ventilated cabinets and sensors to reduce chemical

exposure, and only ultimately resorting to PPE. This

conceptual framework guides decision-making towards

more effective and sustainable solutions, avoiding relying

exclusively on reactive measures [17].

1.3.- Good Practices and 5S

Good Manufacturing Practices with 5S order establish an

organized environment that reduces spills and confusion of

reagents, reducing slips and burns in dairy plants [7, 11].

Participatory ergonomics, which involve operators in

redesigning their tasks (adjustable tables, motorized carts,

passive exoskeletons), is associated with 30–35% drops in

RULA/REBA scores and concomitantly decreased

absenteeism and turnover [6, 8, 13–15]. Digital

lockout/tagout linked to predictive maintenance makes it

possible to document and anticipate failures in CIP pumps

and other critical equipment, prolonging MTBF and

reducing serious mechanical accidents by around 25–30%

[12].

Figure 1. Risk reduction in the dairy industry.

In the Ecuadorian context, previous studies on occupational

risk assessment in artisanal cheese factories and dairy plants

in different provinces highlight ergonomic, chemical, and

thermal risks, but lack integrated analysis of interventions

and prolonged follow-up [35–42]. This underscores the

need to adapt and validate interventions tested in other

countries in Ecuador.

Good Manufacturing Practices (GMP), complemented by

the 5S methodology, constitute the basis for risk prevention

in dairy environments. These organizational tools promote

cleanliness, order, and standardization, reducing the

likelihood of minor accidents such as slips, falls, and

chemical burns. The systematic implementation of 5S audits

and BPM checklists not only improves physical security but

also strengthens operational discipline, creating an

environment conducive to the adoption of more advanced

controls [47–50].

International and local evidence confirms that maturity in

BPM correlates with positive safety indicators, such as a

decrease in incidents and an improvement in organizational

climate. In Ecuadorian plants, the gradual application of

these practices has proven to be a cost-effective strategy,

especially in SMEs with limited resources. In addition, the

integration of GMP and 5S facilitates traceability and

regulatory compliance, key aspects to access markets that

require quality and food safety certifications [56–60].

Table 1

Concept

Operational definition

Verification

indicator

Good

Manufacturin

A set of organisational and

hygienic criteria that

BPM Maturity

Index: percentage

20%

32.5%

27.5%

19%

35%

BPM + 55

(Derrames/Quemaduras)

Ergonomía Participativa

(RULA/REBA)

Bloqueo-Etiquetado Digital

(Accidentes Mecánicos)

Gabinetes Ventilados

(Quemaduras Cáusticas)

ISO 45001+ISO 22000

(Severidad de Incidentes)

Porcentaje de Reducción (%)

Prácticas de Seguridad

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Chemical Engineering & Development

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e – ISSN: 3028-8533

ISSN – L: 3028-8533

Chemical Engineering & Development

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Guayaquil – Ecuador

https://revistas.ug.edu.ec/index.php/iqd

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Pag. 31

g Practices +

guarantee orderly spaces,

separation of flows (dry/wet)

and clear labelling of

substances, in order to reduce

spills and confusion that lead

to accidents.

of items fulfilled in

5S audit.

Participatory

ergonomics

Collaborative process where

operators and specialists

identify biomechanical risk

factors and design

improvements (station

adjustment, mechanical aids,

passive exoskeletons) to

reduce loads and forced

postures.

Decrease in

RULA/REBA

scores ≥ 30% after

intervention.

Digital

Lockout/Tago

ut (LOTO)

Hazardous energy isolation

procedure supported by

digital tools (electronic

checklists, QR codes,

traceability on the platform)

to guarantee systematic

verification before any

intervention in equipment.

LOTO protocol

compliance rate: %

of interventions

with complete

digital registration.

Predictive

maintenance

Condition monitoring of

critical equipment using

sensors (vibration,

temperature, ultrasound) and

data analysis to anticipate

failures, schedule safe

shutdowns, and avoid

unexpected breakdowns.

MTBF (Mean Time

Between Failures)

and percentage of

successful

predictive alerts.

CIP ventilated

cabinets

Containment systems and

localized extraction of vapors

generated in clean-in-place

(CIP) processes, so that direct

exposure of operators to

corrosive solutions is

minimized.

Measurement of

environmental

concentration (pH

or pollutants) and

reduction in the rate

of chemical burns.

Ammonia

Sensors

Electrochemical devices

installed in refrigeration areas

to continuously measure

ammonia levels and trigger

alarms before critical

thresholds are exceeded,

avoiding acute exposures.

Number of

exposures >

threshold before

and after

installation (ideal: 0

after intervention)

and false alarm rate.

Climate of

safety

Collective perception of

workers about the

organization's commitment to

prevention and safety,

reflected in attitudes, incident

reporting, and near-misses.

Standardized

survey score (0–

100) and near-

miss/accident

report ratio.

Integrated

management

systems (ISO

45001 + ISO

22000)

Documentary and process

framework that merges

occupational health and food

safety, promoting continuous

improvement and aligning

safety practices with

regulatory and quality

requirements.

Level of

implementation

(degree of

compliance with

clauses) and

correlation with

improvement in

climate and

reduction in

incident severity.

The available evidence on occupational safety in the dairy

industry can be grouped into five lines of intervention

which, when combined, describe a successive-layer

preventive approach. The most relevant findings are

summarized below, prepared exclusively from the sixty

references previously listed.

1.4.- Participatory ergonomics

In industrialized environments in North America and

Europe, participatory ergonomics—which involves the

worker in the reconfiguration of his or her workstation—has

achieved reductions of 30% to 35% in the RULA/REBA

ratios and in the incidence of musculoskeletal disorders [6],

[8], [13]–[15], [24]. The improvements are associated with

the introduction of adjustable tables, motorized carts and

passive exoskeletons, as well as task rotation plans. Local

studies of hand milking, cheese turning and packaging show

levels of ergonomic risk similar to those described

internationally and point to the feasibility of obtaining

equivalent benefits through programmes adapted to SME

resources [35], [39], [41].

Studies agree that tidying up and cleaning programs reduce

minor accidents—especially slips and chemical burns—by

one-fifth to one-quarter, by eliminating puddles, labeling

substances, and separating transit routes for products and

operators [7]. The Ecuadorian literature, although limited in

follow-up duration, describes comparable improvements in

artisanal plants following the adoption of GMP checklists

and 5S daily routines [35]. These studies confirm that the

basic organization of the environment facilitates the

subsequent incorporation of more sophisticated technical

controls [47], [59].

Participatory ergonomics is based on active collaboration

between workers and specialists to identify biomechanical

risks and propose solutions adapted to the operational

context. This approach not only reduces the physical load

through table height adjustments, incorporation of

mechanical aids and task rotation, but also increases staff

commitment to safety. Recent literature highlights that

direct participation improves the acceptance of measures

and accelerates their implementation, which translates into

a sustained decrease in musculoskeletal injuries and

absenteeism from work [11], [12].

In Ecuadorian dairy plants, where manual processes and

small spaces predominate, participatory ergonomics offers

significant advantages over standardized solutions. Pilot

programs have shown that low-cost interventions—such as

passive exoskeletons and motorized mold transport carts—

can reduce RULA and REBA scores by up to 30 percent. In

addition, this approach contributes to improving the

perception of well-being and staff retention, critical factors

in SMEs with high turnover and budget constraints [37],

[50].

1.5.- Digital LOTO and predictive maintenance.

The digitalization of LOTO procedures, combined with

condition monitoring systems, has increased the traceability

of interventions and doubled the MTBF of CIP pumps and

homogenization valves, with the consequent reduction —

between 25% and 30%— of entrapments and amputations,

[17]. In Ecuador, incident analyses indicate that the absence

of a structured LOTO protocol is one of the main causes of

serious accidents; theses and local reports suggest that low-

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Chemical Engineering & Development

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Guayaquil – Ecuador

https://revistas.ug.edu.ec/index.php/iqd

Email: inquide@ug.edu.ec

francisco.duquea@ug.edu.ec

Pag. 32

cost digital tools (mobile applications, QR codes) could fill

this gap [42].

The digitalization of lockout/tagout (LOTO) procedures

represents a substantial advance in hazardous energy

management. By incorporating tools such as QR codes,

electronic checklists and traceability on mobile platforms,

systematic verification is guaranteed before intervening

critical equipment. This practice reduces human errors and

facilitates internal and external audits, strengthening the

safety culture. Combined with predictive maintenance,

digitalization makes it possible to anticipate failures

through data analysis and early warnings, avoiding

unplanned stops and serious accidents [40], [43].

In the context of the Ecuadorian dairy industry, the adoption

of digital LOTO and predictive sensors is especially

relevant for CIP equipment, pumps and homogenization

valves, where failures can lead to entrapment and chemical

burns. International studies report MTBF increases of more

than 40% after the joint implementation of these practices,

while local experiences suggest that low-cost mobile

applications can cover the technological gap in SMEs. This

integration not only improves safety, but also optimizes

operational efficiency and reduces costs associated with

reactive maintenance [25], [28].

In order to meet the objective set, it is proposed to

decompose it into 5 stages: as a first step, to describe the

main risk factors in dairy plants according to the literature;

compare the effectiveness of BPM+5S, participatory

ergonomics, digital LOTO + predictive maintenance, and

chemical management; as a second step, the influence of

ISO 45001+ISO 22000 management systems on climate

and incident severity will be evaluated; As a third step, we

will proceed to identify barriers and facilitators to

implement these measures in Ecuadorian SMEs; As a fifth

step, we will proceed to propose lines of research to address

gaps (prolonged follow-ups, standardized metrics,

adaptation to scale) [56].

1.6.- Chemical and sensor management.

In the chemical field, ventilated clean-in-place cabinets and

ammonia sensors in cold rooms neutralize hazardous

vapors, eliminate exposures above critical thresholds, and

reduce caustic burns ~19% [18, 20, 22].

Ventilated cabinets installed in CIP cleaning zones keep

alkaline vapors below irritating levels and have cut caustic

burns by about 19% [18], [20]. In addition, electrochemical

ammonia sensors eliminate peaks above 25 ppm and have

false alarm rates of less than 3% [18]. Ecuadorian

monitoring confirms the presence of worrying

concentrations of ammonia and the extensive use of caustic

detergents without adequate containment; Therefore, the

gradual incorporation of cabinets and sensors is a priority,

even in medium-scale plants.

The handling of caustic substances in clean-in-place (CIP)

processes and the use of ammonia in refrigeration systems

are critical chemical hazards in the dairy industry. The

installation of ventilated cabinets and localized extraction

systems minimizes exposure to corrosive vapors, while

electrochemical sensors allow ammonia concentrations to

be monitored in real time, triggering alarms before

dangerous thresholds are reached. These measures, aligned

with international standards, reduce the incidence of

chemical burns and acute poisoning events [22].

In Ecuador, studies have shown worrying levels of

ammonia in cold rooms and deficient practices in the

handling of caustic detergents. The gradual incorporation of

ventilated cabinets and basic sensors is emerging as a cost-

effective strategy for SMEs, complemented by training

programs on chemical safety protocols. In addition, the

integration of these controls with digital registration

systems strengthens traceability and facilitates emergency

response, consolidating a robust preventive approach to

chemical risks [57].

1.7.- ISO integrated systems (ISO 45001 + ISO 22000).

Plants that merge occupational health management with

food safety better communicate safety priorities and achieve

reductions in accident severity of close to 35% [29]. Local

experiences in the design of safety and health systems show

that, although SMEs face budget constraints, alignment

with international standards favors a stronger safety climate

and facilitates access to markets that require certifications

[49].

The integration of ISO 45001 (occupational health and

safety) and ISO 22000 (food safety) management systems

provides a robust framework for risk prevention in the dairy

industry. This synergy allows aligning safety objectives

with quality standards, generating more efficient and

auditable processes. The literature indicates that the joint

adoption of these standards not only reduces the severity of

accidents, but also improves the perception of the

organizational climate, increasing the active participation of

workers in the preventive culture [58].

In the Ecuadorian context, the implementation of integrated

systems faces challenges such as budgetary limitations and

lack of specialized personnel. However, regional studies

show that ISO certification acts as a catalyst for continuous

improvement, facilitating access to international markets

and strengthening the competitiveness of SMEs. In

addition, document and procedural integration reduces

duplication, optimizes resources and ensures regulatory

compliance, consolidating a sustainable preventive

approach [25].

Finally, integrating these practices into an ISO 45001 + ISO

22000 management system reinforces the safety culture,

improves climate perceptions, and reduces incident

severity.

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Email: inquide@ug.edu.ec

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Pag. 33

1.8.- Sociotechnical perspective and sustainability.

The reviewed works converge in that no single measure

offers comprehensive protection; It is the strategic

overlapping of controls – from basic order to advanced

monitoring – that achieves sustained reductions in the

accident rate. International evidence provides robust

quantitative data, while Ecuadorian literature provides the

contextual perspective needed to adapt such interventions to

small and medium-sized plants [46].

Occupational safety in the dairy industry must be

approached from a socio-technical perspective, which

recognizes the interaction between human, technological

and organizational factors. This approach considers that

accidents are not the exclusive product of individual errors,

but of failures in complex systems where management

decisions, equipment design and preventive culture

converge. Incorporating this vision allows for the design of

interventions that integrate technology, training, and

leadership, ensuring sustained risk reduction [10].

Sustainability adds a strategic dimension to risk analysis,

linking worker protection with environmental and social

responsibility. Preventive practices, such as participatory

ergonomics and safe chemical management, contribute to

the Sustainable Development Goals (SDGs), especially

SDG 3 (good health and well-being) and SDG 8 (decent

work). Likewise, the digitalisation of processes and the use

of advanced sensors reduce waste and emissions, aligning

industrial safety with energy efficiency and the circular

economy. This comprehensive approach positions the dairy

industry as a key player in the transition to safer and more

sustainable production systems [28, 29].

The objective of this research is to analyze the efficacy and

feasibility of preventive interventions in the dairy industry,

based on the evidence of 60 references, with a special focus

on adaptations for Ecuador.

2.- Materials and methods.

2.1 Description of materials and equipment

• Bibliographic sources: Sixty previously identified

documents (42 scientific articles, 7 theses, 2 books, 7

standards-technical reports, 2 conference proceedings).

• IT tools:

o Microsoft Excel 365 for creating the extraction

template and calculating descriptive statistics.

o Microsoft Word 365 as a reference manager and for

automatic metadata checking.

o Microsoft Word 365 for collaborative writing and

change control.

o Lucidchart for creating conceptual schematics of

control layers (for internal visualization only; not

included in the final manuscript).

2.2 Study design

A critical narrative review design with a mixed approach

was adopted. The variables of interest—defined a priori—

included: type of intervention, duration, sample size,

outcome indicators (accident rate, RULA/REBA indices,

MTBF, chemical concentrations, safety climate) and

context (plant size, certifications, degree of automation).

• Internal validity control: sequential double reading;

the first extraction was performed by one author and the

verification by another, discussing discrepancies until

consensus was reached.

• Inclusion criteria: publications that describe

occupational hazards or preventive interventions in the

dairy industry (or similar settings) and report, at least

qualitatively, related effects or metrics.

• Exclusion criteria: reports without original data or

applicable analysis (e.g. press releases or strictly

commercial documents).

2.3 Procedures

1. Initial classification: grouping of the 60 references

according to document type and assignment of thematic

categories.

2. Data extraction: completion of the template in Excel

365, recording: author, year, country, design, sample,

intervention, duration, pre/post indicators and quality

observations.

3. Cross-review: Second researcher reviewed each entry,

contrasted values, and filled in missing fields.

4. Quality assessment: application of an internal

qualitative rubric (high, moderate, low robustness)

based on design, size and clarity of results.

5. Narrative synthesis: writing summaries by

intervention block and elaboration of comparative

tables.

6. Specific quantitative aggregates: calculation of

means and percentage reduction ranges when at least

three studies reported the same indicator in a

homogeneous manner.

2.4 Data analysis

• Descriptive statistics: arithmetic means, ranges and

standard deviations generated in Excel 365

(AVERAGE, STDEV. P, MIN, MAX).

• Internal visualization: Bar charts and scatter plots

produced in the same spreadsheet to detect patterns

(e.g., relationship between automation and accident

reduction).

• Qualitative triangulation: comparison of findings

between studies of high and moderate level of evidence

to identify convergences and divergences.

2.5 Ethical considerations

The research is based exclusively on published literature

and does not involve humans, animals, or personal data.

Therefore, the approval of an ethics committee was not

necessary.

3.- Results.

3.1 Overall description of the data

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Pag. 34

A total of 108 quantitative observations were compiled from

32 studies with pre- and post-intervention values. 75 % of

the observations come from peer-reviewed articles; the rest

come from applied theses and technical reports.

Table 2. Weighted averages

Intervention

Key indicator

Average

pre

Post

average

Change

(%)

BPM + 5S

Accident rate

(×10⁶ h-man)

7.4

5.8

–22

Participatory

ergonomics

RULA Index

7.2

5.0

–32

Digital +

Predictive

LOTO

Serious

mechanical

accidents

(×10⁶ h-man)

6.1

4.4

–27

Chemical

management

(cabinet +

NH₃)

Chemical

burns

(cases/year)

9.7

–19

ISO 45001 +

ISO 22000

Severity of

incidents

(days

lost/case)

6.5

4.2

–36

3.2 Results by line of intervention

3.2.1 Good Manufacturing Practices + 5S

Studies agree on decreases in accidents of less than 20% to

24%. The effect is explained by three recurrent factors: (i)

reduction of puddles in wet areas, (ii) elimination of

misplaced materials and (iii) systematic signaling of caustic

products. Two Ecuadorian studies confirm the same pattern,

albeit on smaller scales.

3.2.2 Participatory ergonomics

The weighted mean shows a 32% decrease in the RULA

index and a similar cut in the prevalence of MSDs. Figure 2

visualizes the drop in the average score (from 7.2 to 5.0).

These values reproduce the magnitude reported in

international meta-analyses, suggesting that the principles

of participation and redesign can be successfully translated

into resource-constrained contexts.

Figure 2. Impact of participatory ergonomics on the RULA index

3.2.3 Digital Lockout/Tagout + Predictive Maintenance

The simultaneous implementation of both practices doubled

the MTBF of CIP pumps (from 38 to 52 days) and reduced

serious mechanical accidents by 27%. The effect is

attributed to real-time digital verification (QR codes) and

the triggering of predictive alerts that allow shutdowns to be

scheduled in low-production windows.

3.2.4 Chemicals and air quality management

Ventilated cabinets cut 19% of caustic burns; Ammonia

sensors eliminated exposures > 25 ppm. The greatest benefit

was observed in chambers with older cooling systems,

where reactive maintenance was costly and infrequent.

Figure 3. Average effectiveness of each intervention

3.2.5 ISO 45001 + ISO 22000 Management Systems

Co-adoption yielded the largest reduction in severity (-

36%). Studies point to improvements in reporting culture

and an average increase of 15 points in safety climate

surveys.

3.3 Cross-cutting trends

An exploratory analysis (not shown graphically) found an

inverse correlation (r = -0.63) between the level of

automation and the frequency of mechanical accidents after

the LOTO-predictive intervention. This suggests that

combining digitalization with some modernization of

equipment boosts results.

3.4 Interpretation vs. objectives

The data confirm the objectives formulated:

• Objective 1. The predominant risk factors were

ergonomic, mechanical and chemical; biological

factors were relegated to primary milking plants.

• Objective 2. Participatory ergonomics and the LOTO-

predictive package are the ones that offer the greatest

return in the short term.

Pre intervencion Post intervencion

Puntuacion RULA promedio

BPM + 5S LOTO + predictivo ISO 45001 + ISO

22000

Figura 3. Efectividad promedio de cada

intervención

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• Objective 3. The ISO implementation is corroborated

as a catalyst for cultural and technical improvements.

• Objective 4. The main barriers in Ecuadorian SMEs

are initial investment and staff turnover; the facilitators

are cooperative culture and public technical assistance

programs.

3.5 Practical and theoretical implications

• Practices: Prioritise participatory ergonomics as an

"entry" to the preventive culture and use its successes

to justify investment in sensors and cabinets.

• Theoretical: The findings strengthen the hypothesis of

overlapping barriers and provide specific quantification

for the dairy chain, an area that has been little addressed

in previous studies of sociotechnical systems.

3.6 Limitations and sources of bias

Table 3

Source of

limitation

Potential impact on

the results

Mitigation strategy

Metric

heterogeneity

Variability between

indicators makes

comparison difficult and

limits a formal meta-

analysis of the results.

It was decided to report

weighted averages and

descriptive ranges of

the indicators.

Follow-ups ≤

18 months

Short duration of

follow-ups generates

uncertainty about the

sustainability and

durability of the effects.

Longitudinal studies

with follow-ups of

more than 18 months

are recommended in

order to evaluate the

persistence of the

effects over time.

Predominance

of large plants

The predominance of

large plants in the

sample may lead to an

overestimation of the

observed effects.

To mitigate this bias, a

differentiated

discussion for the

Ecuadorian context was

included.

Publication

bias

There is a risk that

results with negative or

no findings have been

underrepresented.

Non-indexed theses

and local reports will

be included, which may

contain relevant

information and results

of studies with negative

findings.

Partial conclusion of the analysis: Data convergence

suggests that the sequence of interventions "BPM+5S →

participatory ergonomics → LOTO-predictive → integrated

chemical management → ISO" generates a scalable

preventive maturity trajectory. However, the results should

be interpreted with caution due to the identified limitations,

especially the heterogeneity in the metrics and the

predominance of large plants in the sample. This bias could

affect the extrapolation of results to small and medium-

sized enterprise (SME) contexts, where operating

conditions and resources are very different. Despite these

limitations, the consistency observed among studies

supports the progressive applicability of this approach in

Ecuadorian dairy plants.

4.- Discussion

4.1 Interpretation of the results

The findings confirm that security in the dairy industry is

strengthened when preventive measures are articulated as a

network of complementary defenses. The percentage

reductions observed (22% with BPM + 5S, 32% after

participatory ergonomics, 27% when digitizing LOTO and

applying predictive maintenance, 19% with chemical

controls, 36% after ISO certification) confirm the

sociotechnical premise that the probability of an accident

decreases as the number of independent barriers increases.

Each layer protects a different front: the organization of the

space avoids minor incidents; the ergonomic redesign

mitigates musculoskeletal overloads; energy management

and predictive analytics limit high-impact mechanical

events; chemical containment and monitoring prevent acute

exposures; and the ISO management system integrates all

parts under a structured improvement cycle.

4.2 Comparison with literature

The magnitudes are within the ranges reported for European

and North American plants, which reinforces the external

validity of the results. Two matrices stand out:

1. The chemical benefit was somewhat lower in

Ecuadorian facilities, possibly due to cabinets with

lower capacity and less rigorous maintenance.

2. The jump in the safety climate after ISO certification

exceeded the global average, an indication that the

formalization of procedures generates a particularly

visible impact in environments where the preventive

culture is still in consolidation.

In this way, the review contributes to closing the regional

gap pointed out by the literature, providing data specific to

the Latin American reality and, in particular, to small and

medium-sized plants.

4.3 Theoretical and practical implications

Theoretical perspective. The results provide empirical

support for the model of overlapping barriers, showing that

administrative, technical and cultural controls act

synergistically. This specific quantification for the dairy

chain expands the evidence base in a sector that is scarcely

treated in the literature of sociotechnical systems.

Practical perspective. For Ecuadorian plants, a viable

itinerary is outlined:

1. Strengthen order and signage through BPM + 5S.

2. Introduce participatory ergonomics to immediately

address the greatest source of temporary disability.

3. Implement digital LOTO and predictive sensors,

reducing unplanned stops.

4. Incorporate ventilated enclosures and ammonia sensors

to neutralize critical chemical hazards.

5. Close the loop with an integrated ISO system, which

consolidates the safety culture and facilitates external

audits.

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Pag. 36

4.4 Limitations and recommendations

Identified limitations:

• Variability in designs and metrics that prevents a

statistically robust meta-analysis.

• Scarcity of series with follow-up of more than 18

months, which restricts the sustainability assessment.

• Predominance of data from medium and large-scale

plants, with less representation of micro-enterprises.

• Possible underreporting of studies with neutral or

negative results.

Recommendations for future research

1. Develop longitudinal studies (> 24 months) in SMEs,

quantifying economic and cultural returns.

2. Establish a core of comparable indicators

(accidents/10⁶ h-man, standardised RULA, MTBF,

NH₃ levels) for national monitoring.

3. To explore the influence of psychosocial and gender

factors on the effectiveness of ergonomic interventions.

4. Design financing and technical assistance schemes that

facilitate the adoption of low-cost solutions in micro

and small plants.

Overall, the present discussion integrates the results with

the conceptual framework and offers a realistic roadmap for

raising safety in the dairy industry, while pointing out areas

where knowledge remains insufficient and deserves further

research.

5.- Conclusions.

5.1 Synthesis of findings

The evidence gathered shows that the accident rate in dairy

plants is not tackled by a single resource, but by an

architecture of mutually reinforcing defences. When

tidiness and cleanliness (BPM+5S) become ingrained in the

daily routine, minor incidents fall by around a fifth [7], [11].

If, in addition, the staff themselves collaborate in

redesigning their tasks – the core of participatory

ergonomics – musculoskeletal ailments fall by almost a

third [6], [13].

By digitizing lockout/tagout and linking it to predictive

maintenance, catastrophic failures of critical equipment lose

about a quarter of their frequency [10], [17]. Ventilated

cabinets and ammonia sensorization add a chemical shield

that cuts off almost a fifth of burns [18], [22]. Finally, the

ISO 45001 seal accompanied by ISO 22000 consolidates the

set and achieves the greatest drop in accident severity (≈

36%) [25], [29].

5.2 Main contributions

• Preventive maturity route. A feasible sequence is

described—"order, ergonomics, energy control,

chemical containment, ISO management"—that guides

plants from rapid improvements to a robust system.

• Compact metric package. By converging on four

indicators (accidents/10⁶ h-man, adjusted RULA,

MTBF and NH₃ ppm), dialogue between technicians,

auditors and regulators is facilitated.

• Evidence of Latin American context. The inclusion of

cases from Ecuador and Mexico reduces the regional

gap and demonstrates that high-impact solutions are

transferable to scenarios with limited resources.

5.3 Practical implications

For plant engineers, participatory ergonomics and digital

LOTO emerge as "early wins" that build credibility and free

up productive time. Ecuadorian SMEs, with tight budgets,

can obtain modular financing for ventilated cabinets and

basic sensors, while state agencies adopt the package of

indicators as a tool for targeted inspection.

5.4 Theoretical projection and future agenda

The results reinforce sociotechnical theory: barriers of a

different nature, when overlapped, reduce the likelihood

that latent and active faults will align [1], [3]. There remain,

however, three lines to explore:

1. Follow-ups of at least two years to verify the technical

and cultural durability of the interventions.

2. Psychosocial studies that measure how leadership and

gender modulate ergonomic effectiveness [29], [42].

3. Cost-benefit models in micro-plants, to quantify the

return of low-cost and high-impact solutions.

Together, the work provides a bridge between safety

systems theory and the day-to-day practice of the dairy

industry, and lays the groundwork for future research to

delve into where questions remain.

6.- Contributions of the authors (Taxonomy of

contributors' roles - CRediT)

1. Conceptualization: (Mayerly Mejía, Carlos Velasquez)

2. Data curation: (Mayerly Mejía, Iván Viteri)

3. Formal analysis: (Carlos Velasquez, Iván Viteri)

4. Research: (Mayerly Mejía, Carlos Velasquez, Iván

Viteri)

5. Methodology: (Mayerly Mejía, Carlos Velasquez)

6. Project Management: (Mayerly Mejía)

7. Supervision: (Carlos Velasquez)

8. Validation: (Iván Viteri, Carlos Velasquez)

9. Visualization: (Mayerly Mejía)

10. Writing - original draft: (Mayerly Mejía, Iván Viteri,

Carlos Velasquez)

11. Writing - revision and editing: (Mayerly Mejía)

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Pag. 37 
 
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Pag. 38

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