Dairy Workers Research Articles

Harmful biological agents in the working environment of dairy plant workers

Occupational hazards for dairy plant workers include contact with bioaerosols emitted during the production process, contact with raw milk, or with animals in the case of small home-based milk processing plants. Dairy plant workers can be exposed to biological agents, such as bacteria, fungi and viruses, which are responsible for various diseases and adverse health outcomes. Therefore, reliable risk assessment and appropriate preventive measures are key to occupational hazard prevention among this group of workers.

Personal exposure of dairy workers to dust, endotoxin, muramic acid, ergosterol, and ammonia on large-scale dairies in the high plains Western United States

ABSTRACTDairy workers experience a high degree of bioaerosol exposure, composed of an array of biological and chemical constituents, which have been tied to adverse health effects. A better understanding of the variation in the magnitude and composition of exposures by task is needed to inform worker protection strategies. To characterize the levels and types of exposures, 115 dairy workers grouped into three task categories on nine farms in the high plains Western United States underwent personal monitoring for inhalable dust, endotoxin, 3-hydroxy fatty acids (3-OHFA), muramic acid, ergosterol, and ammonia through one work shift. Eighty-nine percent of dairy workers were exposed to endotoxin at concentrations exceeding the recommended exposure guidelines (adjusted for a long work shift). The proportion of workers with exposures exceeding recommended guidelines was lower for inhalable dust (12%), and ammonia (1%). Ergosterol exposures were only measurable on 28% of samples, primarily among medical workers and feed handlers. Milking parlor workers were exposed to significantly higher inhalable dust, endotoxin, 3-OHFA, ammonia, and muramic acid concentrations compared to workers performing other tasks. Development of large modern dairies has successfully made progress in reducing worker exposures and lung disease prevalence. However, exposure to endotoxin, dust, and ammonia continues to present a significant risk to worker health on North American dairies, especially for workers in milking parlors. This study was among the first to concurrently evaluate occupational exposure to assayable endotoxin (lipid A), 3-hydroxy fatty acids or 3-OHFA (a chemical measure of cell bound and noncell-bound endotoxins), muramic acid, ergosterol, and ammonia among workers on Western U.S. dairies. There remains a need for cost-effective, culturally acceptable intervention strategies integrated in OHS Risk Management and production systems to further optimize worker health and farm productivity.

Zoonotic Importance of Some Pathogenic Bacteria Isolated from Small Ruminants' Milk and Hands of Dairy Workers

Zoonotic Importance of Some Pathogenic Bacteria Isolated from Small Ruminants' Milk and Hands of Dairy Workers

Milk hygiene practices of dairy workers of Milk Colony, Dhanas, Chandigarh

Milk hygiene practices of dairy workers of Milk Colony, Dhanas, Chandigarh

Zoonotic Importance of Some Pathogenic Bacteria Isolated from Small Ruminants' Milk and Hands of Dairy Workers

Staphylococcus aureus and enteropathogenic Escherichia coli are among zoonotic bacterial food-borne pathogens causing illness ranged from diarrhoea to fatal conditions. This study was undertaken to evaluate the occurrence of Staph. aureus and E. coli in small ruminants' raw milk and hands of dairy workers at small-scale production units, Giza, Egypt. A total of 420 raw milk samples were obtained from apparently healthy sheep and goats, also, hand swabs (n=46) from workers at the units under investigation were examined. Overall, Staph. aureus (13.1%, 55/420) and E. coli (26.2%, 110/420) isolates were obtained from raw milk of sheep and goats. However, only Staph. aureus (15.2%, 7/46) was recovered from hand swabs of dairy workers. Using PCR, all the tested Staph. aureus isolates from milk and hand swabs yielded specific bands of Thermonuclease ( nuc ) gene at 279 bp, however, amplification of virulence ( eae ) gene encoding the intimin protein of E. coli produced an amplicon of 917 bp in 45% of the tested E. coli isolates. In conclusion, our findings provide an overview about Staph. aureus and E. coli contamination in raw milk of small ruminants locally bred by smallholders and suggest probably transmission of Staph. aureus from hands of dairy workers that contaminate the milk or udder of apparently healthy animals. Reporting of such organisms from milk indicates the need for strict hygienic measures during milking at these production units.

Sensitization to cow’s milk protein in a dairy worker

Repeated skin exposure and inhalation of milk proteins may lead to IgE-mediated sensitization, normally manifested at the site of contact. Although this is a phenomenon predominantly found in children, it has also been observed in adults. To describe a case of a worker who, after being exposed to milk proteins for many years, eventually experienced episodes of anaphylaxis. A 62-year-old worker experienced severe episodes of anaphylaxis following the intake of dairy products. He had worked in the dairy industry for 17 years, where he was exposed to dried milk every day. This case report illustrates how continued exposure to milk proteins, either by skin contact or inhalation, may lead to sensitization which could result in severe manifestations of anaphylaxis.

Occurrence and genetic characterization of Staphylococcus aureus in milk samples of cattle with mastitis, and in the Veterinary Hospital personnel and dairy workers

Staphylococcus aureus está entre os microrganismos que apresentam as maiores taxas de morbidade e mortalidade em seres humanos e animais. Linhagens de S. aureus resistentes a meticilina podem causar surtos de infecção em todo o mundo, o que contribui para a escassez de arsenal terapêutico. Este trabalho analisou o perfil epidemiológico de estirpes de S. aureus isoladas de pessoas que trabalham em contato com animais em um hospital veterinário com gado leiteiro e também em amostras de leite de vacas acometidas por mastite. As estirpes de S. aureus isoladas foram caracterizadas fenotipicamente por meio de antibiograma, testes de catalase e coagulase, e pelo teste de Voges-Proskauer. As amostras também foram caracterizadas genotipicamente pela técnica de Analise de Restricao de DNA Ribossomico Amplificado (ARDRA-PCR). Das 218 estirpes isoladas, 27 foram identificados como S. aureus (12%). Entre essas, quatro estirpes foram resistentes a oxacilina e duas classificadas como SARM (S. aureus resistente a meticilina). A ocorrência de estirpes de S.aureus isoladas entre o pessoal que trabalha em contato com os animais foi baixa (2%), mas estirpes identificadas como SARM foram encontradas na equipe clínica. As análises de ARDRA realizadas com as enzimas de restrição HindIII e HinfII demonstraram que S. aureus isolados de diferentes indivíduos que trabalhavam com animais foram agrupados no mesmo cluster. Quando a ARDRA foi realizada com HaeIII foi observada formação de dois grupos, mas os isolados não se correlacionaram. Conclusão: a ocorrência de estirpes de S. aureus isoladas foi maior na equipe clínica, apresentando também correlação de 100% nos ensaios bioquímicos e moleculares.

Listeria monocytogenes in raw milk, milking equipment and dairy workers: Molecular characterization and antimicrobial resistance patterns.

The aim of this study was to evaluate the genetic relatedness and patterns of antimicrobial resistance amongst L. monocytogenes isolated from raw milk, milking equipment, and hand swabs from workers in dairy farms. A total of 300 samples of raw milk, milking equipment, and hand swabs were collected from four dairy farms to examine the presence of Listeria species. Suspected isolates were further identified by VITEK-2 system and Polymerase Chain Reaction (PCR). Antimicrobial susceptibility of the L. monocytogenes isolates was determined, and genotyping analysis was performed by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). Listeria spp. was isolated from 79 (26.3%) of the 300 samples, including 29 (36.7%), 32 (40.5%), and 18 (22.8%) isolates found in raw milk, milking equipment, and hand swabs, respectively. L. monocytogenes was the most common isolated (87.3%) species, while the remaining Listeria isolates were L. innocua (12.7%). Among the 69 L. monocytogenes isolates, 42 (60.8%) showed the mutual presence of hlyA, prfA, inlA, and inlB virulence-associated genes. L. monocytogenes isolates from raw milk, milking equipment, and hand swabs showed high genetic relatedness. The potentially virulent L. monocytogenes isolates were most frequently resistance to tetracycline and clindamycin (81%, each) followed by rifampicin (71.4%), whereas, antimicrobial susceptibility was most frequently observed for ampicillin, levofloxacin, moxifloxacin, linezolid, and tigecycline (100%, each). Furthermore, 88% of L. monocytogenes isolates showed multidrug-resistance. The findings of this study show that the contamination of dairy farms with L. monocytogenes is relatively high, and highlight the emergence of multi-drug resistant L. monocytogenes in dairy farms. However, ampicillin is a good choice for treatment of listeriosis in the study area.

Granulometry, microbial composition and biological activity of dusts collected in French dairy farms

BackgroundDairy working increases the prevalence of lower airway respiratory diseases, especially COPD and asthma. Epidemiological studies have reported that chronic inhalation of organic dusts released during specific daily tasks could represent a major risk factor for development of these pathologies in dairy workers. Knowledge on size, nature and biological activity of such organic dusts remain however limited. ObjectiveTo compare size distribution, microbial composition and cellular effects of dusts liberated by the spreading of straw bedding in five French dairy farms located in Brittany. ResultsMechanized distribution of straw bedding generated a cloud of inhalable dusts in the five dairy farms’ barns. Thoracic particles having a 3–7.5µm size constituted 58.9–68.3% of these dusts. Analyses of thoracic dusts by next generation sequencing showed that the microbial dust composition differed between the five French farms, although Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria represent more than 97.5% of the bacterial phyla detected in each sample. Several bacteria genera comprising of human pathogenic species, such as Pseudomonas, Staphylococcus, Thermoactinomyces or Saccharopolyspora were identified. Cladosporium and Alternaria fungal genera, which are potent environmental determinants of respiratory symptoms, were detected in dusts collected in the five farms and their levels reached 15.5–51.1% and 9–24.7% of assignable fungal sequences in each sample, respectively. Finally, all dust samples significantly and strongly increased the expression of the pro-inflammatory TNF-α, IL-1β, IL-6 and IL-8 cytokines at both mRNA and protein levels in human monocyte-derived macrophages. Their effects were dose-dependent and detectable from 1µg/ml. The intensity of the macrophage responses however differed according to the samples. ConclusionsOur results strengthen the hypothesis that organic dusts released during the distribution of straw bedding are mainly constituted of thoracic particles which are small enough to deposit on lower bronchial epithelium of dairy farmers and induce inflammation.

Performing cleanliness: clean milk competitions in Britain, c.1920–1940

The question of how best to secure a healthy, disease-free milk supply was one of the most contentious public health issues in interwar Britain. Commentators identified improper and unhygienic milking practices as just one area of the dairy industry in desperate need of reform. In the 1920s a loose partnership of agricultural scientists and educators, civil servants, and dairy businesses turned to competition as a means by which to convince milkers as to the benefits of “scientific dairying”. Clean milk competitions came to simultaneously educate and discipline British dairy workers by working to redefine milking skill with the help of the laboratory sciences. However, the venture was a contentious one, wherein competition participants would often resist the meanings and methods that were coming to be employed in the quest for “clean milk”.

Assessment of tobacco dependence among dairy workers, Salem, Tamil Nadu

Assessment of tobacco dependence among dairy workers, Salem, Tamil Nadu

Improving Health Care for Spanish-Speaking Rural Dairy Farm Workers.

Dartmouth Geisel Migrant Health (DGMH) is a medical student group that provides on-site health services for Spanish-speaking dairy workers in rural Vermont and New Hampshire in conjunction with a federally qualified health center (FQHC). This project was undertaken to evaluate and improve the services provided by DGMH and the FQHC and to refine understanding of the target population. We surveyed 25 workers at 6 collaborating dairy farms to identify health priorities and concerns and perceived barriers and facilitators to health care for these workers. Surveys were administered over 2 weeks in July 2015. Interpreter-mediated appointment and sliding-fee-scale data from a period 7 months that spanned survey administration were also assessed. Diabetes and hypertension were the most common health concerns. Thirty-two percent of participants reported 10 or more days of depressed mood in the past month. Insurance and language were the most common barriers to health care and employers and on-site clinics were the most common facilitators. Appointments most often addressed women's health, gastrointestinal problems, health maintenance, diabetes, and back pain. Thirty FQHC sliding-fee-scale applications were completed by workers. These Spanish-speaking dairy-farm workers have many health concerns and perceive substantial barriers to health care. Collaboration between medical students, a rural FQHC, and farm employers provides important services that facilitate health care access among this population.

Assessing the effects of biomechanical overload on dairy parlor workers' wrist: Definition of a study approach and preliminary results.

Dairy milking is a demanding work task that has been associated with hand and wrist musculoskeletal disorders. Clinical approaches to identify the early effects of musculoskeletal disorders among dairy parlor workers' wrist have not been well defined. The purpose of this pilot study was to develop a study protocol that would assist in the identification and quantification of hand and wrist disorders among dairy workers that perform tasks in the dairy parlor. Additionally, such a study protocol was needed to perform relatively rapid assessments of the wrist/hand on large samples of dairy workers. Fourteen dairy parlor workers were assessed for i) upper limb symptoms and work history through questionnaire, ii) a physical examination of the upper limb and in particular wrists and iii) wrist ultrasonography. An additional 21 unexposed paired participants (the control group) also participated in the data collection. The study results identified two ultrasound acoustic windows characterized by the highest predictive value for alteration of the wrist's structure. Study results indicated an impairment of the distal median nerve in structure and mobility and impairment of the distal tendon of the muscle extensor carpi ulnaris that included dislocation and frank damage. This study identified at least two acoustic windows that should be assessed with ultrasound studies on larger groups and in prospective periodical health surveillance of dairy workers. The study confirmed the wrist was at risk for biomechanical stress among workers conducting milking tasks in the dairy parlors.

Applying Learning Theory to Safety and Health Training for Hispanic Immigrant Dairy Workers.

We designed a safety and health curriculum for dairy immigrant workers aiming to increase knowledge, encourage safe behavior, and reduce worker communication inequalities to prevent occupational injury and diseases. The design is largely based on the Taxonomy of Significant Learning and incorporated behavioral and adult learning theories and principles of occupational hazard control. Trainings were implemented with 836 Spanish-speaking workers from 67 farms in Wisconsin. Sixty-seven percent of workers reported never being trained before in dairy safety, 65% of these worked in dairy for 5 or fewers years, and 26% of workers reported being ever injured while working on dairy. Quantitative and qualitative evaluation of the trainings suggest that our curriculum successfully increased worker knowledge and promoted contemplation of safe practices. The overall knowledge gain of 25% was statistically significant ( p < .01). Workers recalled at least one key concept, expressed confidence of adopting at least one safety behavior, and mentioned their intention to communicate safety concerns to farmers. To our knowledge, this is the first Taxonomy of Significant Learning application to occupational safety and health education. Our curriculum can support dairy farmers' compliance with Occupational Safety and Health Administration's annual training requirements by providing our basic safety and health training to workers at early job stages.

Occurrence, genotyping, shiga toxin genes and associated risk factors of E. coli isolated from dairy farms, handlers and milk consumers

The objectives of the current study were to determine the occurrence and genotypes of E. coli in dairy farms, workers and milk consumers and to evaluate risk factors associated with contamination of milk in dairy farms. Molecular characterization of shiga toxin associated genes and enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) finger printing of E. coli from different sources were also studied. Paired milk samples and rectal swabs from 125 dairy cows, rectal swabs from 82 calves and hand swabs from 45 dairy workers from five dairy farms were collected. In addition, 100 stool samples from 70 diarrheic and 30 healthy humans were collected and examined for the presence of E. coli.E. coli was isolated from milk (22.4%), dairy cattle feces (33.6%), calf feces (35.4%), dairy worker hand swabs (11.1%) and stools of milk consumers (2%, from diarrheic patients only). Only stx1 was identified in seven of 12 E. coli O125 isolated from different sources. High genetic diversity was determined (Simpson's index of diversity, D = 1) and E. coli O125 isolates were classified into 12 distinct profiles, E1–E12. The dendrogram analysis showed that two main clusters were generated. Mastitis in dairy cows was considered a risk factor associated with contamination of the produced milk with E. coli. The isolation of E. coli from rectal swabs of dairy cows and calves poses a zoonotic risk through consumption of unpasteurized contaminated dairy milk. Educational awareness should be developed to address risks related to consumption of raw milk.

Effect of Dairy Beef Quality Assurance Training on Dairy Worker Knowledge and Welfare-Related Practices

A study was conducted to determine whether on-farm dairy beef quality assurance (BQA) training affected dairy worker knowledge of BQA and welfare-related practices. Dairy personnel who participated in the BQA training were administered an exam before and after the training to gauge the amount of knowledge gained. The average exam score was 21.0 points higher after the training, increasing from 54.4 to 75.4. Improvement in dairy worker knowledge suggests that BQA training programs have the potential to positively influence the dairy industry through the education of dairy owners and workers on BQA and welfare-related practices.

Development and Evaluation of a Basic First Aid Curriculum for Spanish-Speaking Dairy Workers.

. Over the past decade, the New York State dairy industry has grown substantially, resulting in an increase in immigrant workers who speak languages other than English. Estimates suggest that over 50% of workers on large New York dairies are Spanish-speaking individuals who immigrated to the U.S. from Guatemala, Mexico, and other Latin American countries. With a growing population of Spanish-speaking workers, safety concerns on farms have become a prominent issue. This article reviews the development and evaluation of a basic dairy first aid curriculum, which is intended to educate Spanish-speaking immigrant dairy workers on emergency response and first aid. The materials developed are culturally relevant and can be easily understood by low-literacy, non-English-speaking workers. In evaluation of the materials using pre- and post-testing, a significant knowledge gain was identified in workers who participated in the training.

Occupational Health and Safety of Finnish Dairy Farmers Using Automatic Milking Systems.

Conventional pipeline and parlor milking expose dairy farmers and workers to adverse health outcomes. In recent years, automatic milking systems (AMS) have gained much popularity in Finland, but the changes in working conditions when changing to AMS are not well known. The aim of this study was to investigate the occupational health and safety risks in using AMS, compared to conventional milking systems (CMS). An anonymous online survey was sent to each Finnish dairy farm with an AMS in 2014. Only those dairy farmers with prior work experience in CMS were included in the final analysis consisting of frequency distributions and descriptive statistics. We received 228 usable responses (131 male and 97 female; 25.2% response rate). The majority of the participants found that AMS had brought flexibility to the organization of farm work, and it had increased leisure time, quality of life, productivity of dairy work, and the attractiveness of dairy farming among the younger generation. In addition, AMS reduced the perceived physical strain on the musculoskeletal system as well as the risk of occupational injuries and diseases, compared to CMS. However, working in close proximity to the cattle, particularly training of heifers to use the AMS, was regarded as a high-risk work task. In addition, the daily cleaning of the AMS and manual handling of rejected milk were regarded as physically demanding. The majority of the participants stated that mental stress caused by the monotonous, repetitive, paced, and hurried work had declined after changing to AMS. However, many indicated increased mental stress because of the demanding management of the AMS. Nightly alarms caused by the AMS, lack of adequately skilled hired labor or farm relief workers, and the 24/7 standby for the AMS were issues that also caused mental stress. Based on this study, AMS may have significant potential in the prevention of adverse health outcomes in milking of dairy cows. In addition, AMS may improve the productivity of dairy work and sustainability of dairy production. However, certain characteristics of the AMS require further attention with regard to occupational health and safety risks.

Comparison of Upper Limb Muscle Activity among Workers in Large-Herd U.S. and Small-Herd Italian Dairies.

Commercial cow milking tasks, regardless of dairy size, have been documented in many regions of the world as strenuous work requiring high muscular effort, awkward positions, and task repetition. Large-herd dairies are common in the U.S., while Europe historically has mostly small-herd dairies. The objective of this study was to compare the upper limb muscle activity during milking tasks between workers at large-herd U.S. dairies and small-herd Italian dairies. This is the first international study directly comparing upper limb muscle activity among dairy workers from different countries using identical methods. Data were collected at 6 large-herd dairies in the U.S. region of Colorado and at 21 small-herd Italian dairies in the Lombardy region. Surface electromyography (sEMG) from the trapezius, anterior deltoid, biceps brachii, wrist flexors, and wrist extensors muscles was recorded from all participating workers (N = 65). Electromyography data were normalized to functional maximum voluntary contractions. Anthropometric measurements were also recorded. Upper limb muscle activity was generally greater among workers in the large-herd U.S. dairies compared with small-herd Italian dairies. The amount of muscular rest as a percent of the work time was significantly greater among large-herd U.S. dairy workers. The differences revealed in sEMG and percent muscular rest among workers from the U.S. and Italy are likely due in part to differences in work processes adopted by fast-paced industrialized large-herd dairies compared with the slower, but sustained work processes performed at small-herd dairies.

Upper Limb Muscle Activity among Workers in Large-Herd Industrialized Dairy Operations.

The primary aim of this cross-sectional research study was to quantify upper limb muscle activity among workers performing milking tasks in large-herd dairy parlors. Surface electromyography (sEMG) from the trapezius, anterior deltoid, biceps brachii, wrist flexors, and wrist extensors muscles of 26 dairy workers were used to create muscle activity profiles for the milking tasks common in large-herd dairy parlors. Functional maximum voluntary contractions (fMVC) were collected to normalize the sEMG data for appropriate comparisons. Anthropometric measurements were recorded from each worker. The biceps brachii had the highest muscle activity (14.58% fMVC) of the upper limb muscles measured, exceeding previously established recommendations for working tasks. The anterior deltoid had the least amount of activity, while the upper trapezius had the least amount of muscular rest during milking work. Worker stature was negatively associated with upper limb muscle activity. Milking tasks in large-herd dairy parlors have significant effects on the upper limb muscle activity of workers. The muscle activity of biceps brachii during normal work tasks exceeded the recommended safe limit. Wrist flexors and upper trapezius approached the recommended limit. The study findings suggest that milking tasks in large-herd dairies may increase the worker's risk for developing musculoskeletal symptoms and possibly musculoskeletal disorders.