Distribution and prevalence of airborne microorganisms in three commercial poultry processing plants

Emerging Technologies for Aerial Decontamination of Food Storage Environments to Eliminate Microbial Cross-Contamination

Air is recognized as an important source of microbial contamination in food production facilities and has the potential to contaminate the food product causing food safety and spoilage issues for the food industry. Potential for aerial microbial contamination of food can be a particular issue during storage in cold rooms when the food is not packaged and is exposed to contaminated air over a prolonged period. Thus, there are potential benefits for the food industry for an aerial decontamination in cold storage facilities. In this paper, aerial decontamination approaches are reviewed and challenges encountered for their applications are discussed. It is considered that current systems may not be completely effective and environmentally friendly, therefore, it is of great significance to consider the development of nonresidual and verified decontamination technologies for the food industry and, in particular, for the cold storage rooms.

Campylobacter contamination of broilers: the role of transport and slaughterhouse

Campylobacter is one of the most important causative agents of foodborne illnesses worldwide. The poultry reservoir is the main source of Campylobacter. Within the broiler production chain, campylobacters can only multiply in the chicken's intestinal tract. Intervention at farm level to reduce Campylobacter is thus preferred, but despite extensive study, no highly effective solutions have been found to combat Campylobacter at farm level. Slaughterhouses are experiencing great pressure to deliver carcasses with low Campylobacter contamination even when they receive and slaughter Campylobacter colonized flocks. Since 2018, a process hygiene criterion (EU 2017/1495) with the critical limit of <1000 cfu/g neck skin has been implemented in EU Member States based on the calculation done at the time of the study that human campylobacteriosis cases could be halved if all carcasses would comply with a criterion of <1000 cfu/g neck skin. This review covers Campylobacter contamination of broiler carcasses from transport through the different slaughter steps. Possible intervention methods during slaughter are discussed with a focus on the European situation, where chemicals are not allowed to disinfect carcasses.

Microbial quality of poultry meat in an ISO 22000:2005 certified poultry processing plant of Kathmandu valley

Poultry meat can be contaminated by different types of microorganisms during processing in processing plant. The microbiological quality of chicken carcasses and along with processing steps and environmental condition was analyzed in this study in an ISO 22000:2005 certified poultry processing plant of Kathmandu. Standard plate count method was applied for the enumeration and detection of total mesophilic bacteria, total coliform, total faecal coliform, Staphylococcus load along with selected pathogens like Salmonella spp., S. aureus, Escherichia coli, Clostridium perfringens, and Listeria spp. in chicken meat at four processing step (evisceration, final washing, frozen and market). It was observed that the level of microbial load decreased with subsequent processing phases in poultry processing plant where high level of bacteria were reduced during final washing and frozen phase. After processing poultry meat in an ISO 22000:2005 certified meat processing plant, total aerobic mesophilic count, total coliform count, total faecal coliform count, total Staphylococcus count were decreased from 6.92 to 4.45 log CFU/g, 3.49 to 2.19 log CFU/g, 2.41 to nil log CFU/g, and 3..43 to 1.99 log CFU/g respectively. Pathogenic bacteria like Salmonella spp., C. perfringens, and Listeria spp. were absent in chicken meat at the fourth processing step. Prevalence of E. coli was reduced from 37.4% to 10.2%, whereas S. aureus was decreased from 18.57% to 17.1%. It was concluded that the final washing and freezing steps were the Critical Control Point (CCP) to control microbial hazards in poultry processing phase.

Exposure to pathogens among workers in a poultry slaughter and processing plant

BACKGROUND

Working conditions in poultry slaughter/processing plants may expose workers to zoonotic pathogens. We explored exposure to pathogens among poultry slaughter/processing plant workers including job duties as risk factors.

METHODS

We collected questionnaire data on job duties and nasal swabs from 110 workers at one plant in South Carolina. Swabs were tested for Staphylococcus aureus and gram-negative organisms. Isolates were screened for antimicrobial susceptibility.

RESULTS

There was no differences in prevalence of S. aureus carriage based on job duties. As compared with office or packing workers, the adjusted odds of GNO carriage was 6.29 times (95% CI: 1.43, 27.71) higher in slaughter or carcass processing workers and 5.94 times (95% CI: 0.94, 37.50) higher in cleaning or maintenance workers.

CONCLUSIONS

Poultry processing plant workers may have increased exposure to GNOs, depending on job duties. Am. J. Ind. Med. 59:453-464, 2016. © 2016 Wiley Periodicals, Inc.

Slaughterhouses Fungal Burden Assessment: A Contribution for the Pursuit of a Better Assessment Strategy

In slaughterhouses, the biological risk is present not only from the direct or indirect contact with animal matter, but also from the exposure to bioaerosols. Fungal contamination was already reported from the floors and walls of slaughterhouses. This study intends to assess fungal contamination by cultural and molecular methods in poultry, swine/bovine and large animal slaughterhouses. Air samples were collected through an impaction method, while surface samples were collected by the swabbing method and subjected to further macro- and micro-scopic observations. In addition, we collected air samples using the impinger method in order to perform real-time quantitative PCR (qPCR) amplification of genes from specific fungal species, namely A. flavus, A. fumigatus and A. ochraceus complexes. Poultry and swine/bovine slaughterhouses presented each two sampling sites that surpass the guideline of 150 CFU/m³. Scopulariopsis candida was the most frequently isolated (59.5%) in poultry slaughterhouse air; Cladosporium sp. (45.7%) in the swine/bovine slaughterhouse; and Penicillium sp. (80.8%) in the large animal slaughterhouse. Molecular tools successfully amplified DNA from the A. fumigatus complex in six sampling sites where the presence of this fungal species was not identified by conventional methods. This study besides suggesting the indicators that are representative of harmful fungal contamination, also indicates a strategy as a protocol to ensure a proper characterization of fungal occupational exposure.

Effects of climate change on the persistence and dispersal of foodborne bacterial pathogens in the outdoor environment: A review

According to the Intergovernmental Panel on Climate Change (IPCC), warming of the climate system is unequivocal. Over the coming century, warming trends such as increased duration and frequency of heat waves and hot extremes are expected in some areas, as well as increased intensity of some storm systems. Climate-induced trends will impact the persistence and dispersal of foodborne pathogens in myriad ways, especially for environmentally ubiquitous and/or zoonotic microorganisms. Animal hosts of foodborne pathogens are also expected to be impacted by climate change through the introduction of increased physiological stress and, in some cases, altered geographic ranges and seasonality. This review article examines the effects of climatic factors, such as temperature, rainfall, drought and wind, on the environmental dispersal and persistence of bacterial foodborne pathogens, namely, Bacillus cereus, Brucella, Campylobacter, Clostridium, Escherichia coli, Listeria monocytogenes, Salmonella, Staphylococcus aureus, Vibrio and Yersinia enterocolitica. These relationships are then used to predict how future climatic changes will impact the activity of these microorganisms in the outdoor environment and associated food safety issues. The development of predictive models that quantify these complex relationships will also be discussed, as well as the potential impacts of climate change on transmission of foodborne disease from animal hosts.

Identification of airborne microbiota in selected areas in a health-care setting in South Africa

BACKGROUND

The role of bio-aerosols in the spread of disease and spoilage of food has been described in numerous studies; nevertheless this information at South African hospitals is limited. Attributable to their size, bio-aerosols may be suspended in the air for long periods placing patients at risk of infection and possibly settling on surfaces resulting in food contamination. The aim of the study is to assess the microbial composition of the air in the kitchen and selected wards at a typical district hospital in South Africa. Air samples were collected using the settle plates and an SAS Super 90 air sampler by impaction on agar. These microbial samples were quantified and identified using Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) and Analytic Profile Index (API).

RESULTS

Microbial counts were found to be higher in the fourth (≤6.0 × 101 cfu/m(-3)) sampling rounds when compared to the first (≥2 cfu/m(-3)), second (≤3.0 × 101 cfu/m(-3)) and third (≤1.5 × 101 cfu/m(-3)) sampling rounds. Genera identified included Bacillus, Kocuria, Staphylococcus, Arthrobacter, Candida, Aureobasidium, Penicillium and Phoma amongst others. The presence of these pathogens is of concern, attributable to their ability to cause diseases in humans especially in those with suppressed host immunity defenses. Furthermore, fungal genera identified (e.g. Candida) in this study are also known to cause food spoilage and fungal infections in patients.

CONCLUSION

Results from this study indicate the importance of air quality monitoring in health-care settings to prevent possible hospital-acquired infections and contamination of hospital surfaces including food contact surfaces by airborne contaminants.

Exposure to airborne culturable microorganisms and endotoxin in two Italian poultry slaughterhouses

Even if slaughterhouses' workers handle large amounts of organic material and are potentially exposed to a wide range of biological agents, relatively little and not recent data are available. The main objective of this study was to characterize indoor concentrations of airborne bacteria, fungi, and endotoxin mod = Im (endotoxin∼Gram-negative*plant*filter) in two Italian poultry slaughterhouses. Air samples near air handling units inlets were also collected. Since there are not standardized protocols for endotoxin sampling and extraction procedures, an additional aim of the study was to compare the extraction efficiency of three different filter.. The study was also aimed at determining the correlation between concentrations of Gram-negative bacteria and endotoxin. In Plant A bacterial levels ranged from 17.5 to 2.6×10(3) CFU/m3. The highest concentrations were observed in evisceration area of chickens, between the automatic detachment of the neck and washing offal, and near birds coupling before hair-chilling. The highest mean value of Gram-negative (266.5 CFU/m3) was found near the washing offal of turkeys. In Plant B bacterial concentration ranged from 35 to 8×10(3) CFU/m3. The highest concentration. with the highest value of Gram-negative (248 CFU/m3), was found after defeathering. Fungal concentrations were overall lower than those found for bacteria (range: 0-205 CFU/m3 in Plant A and 0-146.2 CFU/m3 in Plant B). The microbial flora was dominated by Gram-negative and coagulase-negative staphylococci for bacteria and by species belonging to Cladosporium, Penicillium and Aspergillus genera for molds. The highest endotoxin concentrations were measured in washing offal for Plant A (range: 122.7-165.9 EU/m3) and after defeathering for Plant B (range: 0.83-38.85 EU/m3). In this study airborne microorganisms concentrations were lower than those found in similar occupational settings and below the occupational limits proposed by some authors. However, these microorganisms may exert adverse effects on exposed workers, in particular for those engaged in the early slaughtering stages, as evidenced by the presence of pathogenic species. The detection of pathogenic bacteria near AHU inlet may constitute a risk to public health and environmental pollution.

Airborne microbial composition in a high-throughput poultry slaughtering facility

A high-throughput chicken slaughtering facility in Beijing was systematically investigated for numbers of airborne microorganisms. Samples were assessed for counts of aerobic bacteria, Staphylococcus aureus, total coliforms, Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes, Bacillus cereus, and Salmonella. During a 4-month period (September to December 2011), samples were collected for 10 min three times daily (preproduction, production, and postproduction). Samples were collected for three consecutive days of each month with an FA-1 sampler from six sampling sites: receiving-hanging, soaking-scalding and defeathering, evisceration, precooling, subdividing, and packing. Humidity, temperature, wind velocity, and airborne particulates also were recorded at each sampling site and time. The highest counts of microorganisms were recorded in the initial stages of processing, i.e., the receiving-hanging and defeathering areas, with a definite decline toward the evisceration, prechilling, subdividing, and packing areas; the prechilling area had the lowest microbial counts of 2.4 × 10(3) CFU/m(3). Mean total coliforms counts ranged from 8.4 × 10(3) to 140 CFU/m(3). Maximum E. coli counts were 6.1 × 10(3) CFU/m(3) in the soaking-scalding and defeathering area. B. cereus, P. aeruginosa, and S. aureus represented only a small proportion of the microbial population (1,900 to 20 CFU/m(3)). L. monocytogenes and Salmonella were rarely detected in evisceration, precooling, subdividing, and packing areas. Our study identified the levels of bioaerosols that may affect chicken product quality. This finding could be useful for improved control of microbial contamination to ensure product quality.

Evaluation of hygiene practices and microbiological status of ready-to-eat vegetable salads in Spanish school canteens

BACKGROUND

This study was conducted in eight Spanish school canteens during the period 2008-2009. Food handlers' practices, kitchen equipment, hygiene/sanitation conditions and handling practices were evaluated using checklists. In parallel, the microbiological quality and safety of ready-to-eat (RTE) vegetable salads were assessed. In addition, food contact surfaces and environmental air quality of different areas were analysed. The study determined the relationship between the microbiological quality of RTE foods and food handling practices, together with the degree of contamination of working surfaces and environmental contamination of processing and distribution areas.

RESULTS

Some deficiencies were found regarding the use and change of gloves, hand-washing and cleanliness of working surfaces. The microbial levels detected in the foods examined indicated the absence of pathogens in the samples analysed. Surface counts were higher on cutting boards and faucets, showing insufficient cleanliness procedures.

CONCLUSION

This study constitutes a descriptive analysis of the hygiene/sanitation conditions implemented in food service systems in eight Spanish school canteens. The results should help risk managers to better define control measures to be adopted in order to prevent foodborne infections.

Comparison of aerial counts at different sites in beef and sheep abattoirs and the relationship between aerial and beef carcass contamination

The study examined and compared levels of aerial contamination in commercial beef and sheep plants at four sites, i.e. lairage, hide/fleece pulling, evisceration and chilling. Aerial contamination was determined by impaction and sedimentation onto Plate Count Agar to enumerate Total Viable Counts, MacConkey Agar to enumerate coliforms and Violate Red Bile Glucose Agar to enumerate Enterobacteriaceae. AS I cannot see any difference in the text here - I am not sure what the change is?. The levels of aerial contamination were similar at equivalent sites in beef and sheep plants, irrespective of the sampling method or the type of organisms recovered. Mean log counts recovered on each medium in the chillers were generally significantly lower (P < .05) than the corresponding mean log numbers recovered at the other three sites. The relationship between impaction (air) and sedimentation (surface) counts could be described by the surface to air ratio (SAR) which in this study had an R(2) of 0.77. Further studies in an experimental plant compared counts recovered from the neck of beef carcasses with aerial counts determined by impaction and sedimentation onto agar and irradiated meat pieces. A relationship between counts on beef carcasses and in the air could not be established, irrespective of the method used to compare counts.

Factors of influence in the distribution of mold in the air in a wine cellar

This paper studies the presence of mold in the air of a vinification and ageing wine cellar. The influence of other factors such as the time of year, the sampling point, and the activity being carried out in the cellar has been analyzed. Neither the type of activity being carried out in the cellar nor the temperature or relative humidity fluctuations throughout the year are determining factors in the presence of mold in the air. For this group of microorganisms, the design of the cellar studied is the fundamental factor. Areas with little ventilation favor high levels of relative humidity and, hence, a higher presence of mold in the air. The mold population in these areas is not very diverse, which indicates that colonization by certain types of mold that have adapted to the conditions established therein is permanent. Areas with greater air flow, constant activity, and frequent cleaning show lower mold populations in the air and of a more varied composition.

PRACTICAL APPLICATION

  This work shows that given the growing importance of the presence of mold in wine cellars, the design thereof should take into account suitable ventilation of all the areas and control of the relative humidity. Hence, the presence of traditional underground areas for ageing wine, which is justifiable in seasons where temperature and humidity control lead to major technical problems, should be reconsidered in the design of new wine cellars.

Detection of airborne bacteria in a German turkey house by cultivation-based and molecular methods

Today's large-scale poultry production with densely stocked and enclosed production buildings is often accompanied by very high concentrations of airborne microorganisms leading to a clear health hazard for employees working in such environments. Depending on the expected exposure to microorganisms, work has to be performed under occupational safety conditions. In this study, turkey houses bioaerosols were investigated by cultivation-based and molecular methods in parallel to determine the concentrations and the composition of bacterial community. Results obtained with the molecular approach showed clearly its applicability for qualitative exposure measurements. With both, cultivation-based and molecular methods species of microorganism with a potential health risk for employees (Acinetobacter johnsonii, Aerococcus viridans, Pantoea agglomerans, and Shigella flexneri) were identified. These results underline the necessity of adequate protection measures, including the recommendation to wear breathing masks during work in poultry houses.

Mechanically ventilated broiler sheds: a possible source of aerosolized Salmonella, Campylobacter, and Escherichia coli

This study assessed the levels of two key pathogens, Salmonella and Campylobacter, along with the indicator organism Escherichia coli in aerosols within and outside poultry sheds. The study ranged over a 3-year period on four poultry farms and consisted of six trials across the boiler production cycle of around 55 days. Weekly testing of litter and aerosols was carried out through the cycle. A key point that emerged is that the levels of airborne bacteria are linked to the levels of these bacteria in litter. This hypothesis was demonstrated by E. coli. The typical levels of E. coli in litter were approximately 10(8) CFU g(-1) and, as a consequence, were in the range of 10(2) to 10(4) CFU m(-3) in aerosols, both inside and outside the shed. The external levels were always lower than the internal levels. Salmonella was only present intermittently in litter and at lower levels (10(3) to 10(5) most probable number [MPN] g(-1)) and consequently present only intermittently and at low levels in air inside (range of 0.65 to 4.4 MPN m(-3)) and once outside (2.3 MPN m(-3)). The Salmonella serovars isolated in litter were generally also isolated from aerosols and dust, with the Salmonella serovars Chester and Sofia being the dominant serovars across these interfaces. Campylobacter was detected late in the production cycle, in litter at levels of around 10(7) MPN g(-1). Campylobacter was detected only once inside the shed and then at low levels of 2.2 MPN m(-3). Thus, the public health risk from these organisms in poultry environments via the aerosol pathway is minimal.

The aerobiology of the environment around mechanically ventilated broiler sheds

AIM

To investigate the aerobiology of the environment around mechanically ventilated broiler sheds with the aim of understanding dispersion in the surrounding environment.

METHODS AND RESULTS

Aerosol samples were collected weekly on four different commercial broiler farms through the cycle of 55 days from 2005 to 2007. Samples were collected inside the shed and at varying distances from the sheds. Litter and dust from within the shed were also examined. Members of the genera Staphylococcus (and to a lesser extent Corynebacterium) dominated (10(6) CFU m(-3)) in the outside air at 20 m from the fan and were shown to decrease with distance. At distances of around 400 m, the levels of staphylococci/coryneforms returned to levels typical of those present before the placement of chickens. Escherichia coli levels were low (maximum 100 CFU m(-3)) at 20 m. Fungi were present at uniform levels across the broiler cycle.

CONCLUSIONS

Staphylococci are the dominant organisms present in the air around mechanically ventilated broiler sheds and have the potential to act as an airborne 'marker organism'. SIGNIFICANT IMPACT OF THE STUDY: The outcomes of this study suggest that the impact of aerosols emitted from broiler sheds could be monitored and managed by examining the levels of staphylococci/coryneforms.

Detection of Campylobacter bacteria in air samples for continuous real-time monitoring of Campylobacter colonization in broiler flocks

Improved monitoring tools are important for the control of Campylobacter bacteria in broiler production. In this study, we compare the sensitivities of detection of Campylobacter by PCR with feces, dust, and air samples during the lifetimes of broilers in two poultry houses and conclude that the sensitivity of detection of Campylobacter in air is comparable to that in other sample materials. Profiling of airborne particles in six poultry houses revealed that the aerodynamic conditions were dependent on the age of the chickens and very comparable among different poultry houses, with low proportions of particles in the 0.5- to 2-microm-diameter range and high proportions in the 2- to 5-microm-diameter range. Campylobacter could also be detected by PCR in air samples collected at the hanging stage during the slaughter process but not at the other stages tested at the slaughterhouse. The exploitation of airborne dust in poultry houses as a sample material for the detection of Campylobacter and other pathogens provides an intriguing possibility, in conjunction with new detection technologies, for allowing continuous or semicontinuous monitoring of colonization status.

Effect of a reactive oxygen species-generating system for control of airborne microorganisms in a meat-processing environment

The effectiveness of reactive oxygen species (ROS)-generating AirOcare equipment on the reduction of airborne bacteria in a meat-processing environment was determined. Serratia marcescens and lactic acid bacteria (Lactococcus lactis subsp. lactis and Lactobacillus plantarum) were used to artificially contaminate the air via a six-jet Collison nebulizer. Air in the meat-processing room was sampled immediately after aerosol generation and at various predetermined times at multiple locations by using a Staplex 6 stage air sampler. Approximately a 4-log reduction of the aerial S. marcescens population was observed within 2 h of treatment (P < 0.05) compared to a 1-log reduction in control samples. The S. marcescens populations reduced further by approximately 4.5 log after 24 h of exposure to ROS treatment. Approximately 3-log CFU/m3 reductions in lactic acid bacteria were observed following 2-h ROS exposure. Further ROS exposure reduced lactic acid bacteria in the air; however, the difference in their survival after 24 h of exposure was not significantly different from that observed with the control treatment. S. marcescens bacteria were more sensitive to ROS treatment than the lactic acid bacteria. These findings reveal that ROS treatment using the AirOcare unit significantly reduces airborne S. marcescens and lactic acid bacteria in meat-processing environments within 2 h.

Genotyping of thermotolerant Campylobacter from poultry slaughterhouse by amplified fragment length polymorphism

AIM

To examine the occurrence, diversity and transmission of Campylobacter in a poultry slaughterhouse.

METHODS AND RESULTS

During a 4-week period, a slaughterhouse was sampled alternately during slaughtering and the following mornings post-disinfection. Samples were taken from poultry at six stages in the slaughter process and from 25 environmental sites. For positive broiler flocks slaughtered on one occasion, 92% and 48% of the environmental sites were positive during slaughter and post-disinfection, respectively. For positive laying hen flocks slaughtered on three occasions, 8-56% and 12-20% of the environmental sites were positive during slaughter and post-disinfection, respectively. Genetic fingerprinting by amplified fragment length polymorphism (AFLP) of the 109 isolates obtained resulted in 28 different AFLP clones. Five AFLP clones were present for more than 1 week.

CONCLUSIONS

Slaughtering of Campylobacter-positive broilers resulted in extensive contamination of the slaughterhouse, including the air. A high proportion of the laying hen flocks were Campylobacter positive, but these caused less environmental contamination than the broilers. This, together with the freezing of all layer carcasses, results in a lower public health risk from laying hens, when compared with broilers.

SIGNIFICANCE AND IMPACT OF THE STUDY

When slaughtering Campylobacter-positive broilers, the implementation of preventive measures is important to reduce contamination of negative carcasses and to protect the workers against infection.

Aerosol studies with Listeria innocua and Listeria monocytogenes

Aerosol studies of Listeria monocytogenes in food processing plants have been limited by lack of a suitable surrogate microorganism. The objective of this study was to investigate the potential of using green fluorescent protein-labeled strains of Listeria innocua as a surrogate for L. monocytogenes for aerosol studies. These studies were conducted in a laboratory bioaerosol chamber and a pilot food-processing facility. Four strains of L. innocua and five strains of L. monocytogenes were used. In the laboratory chamber study, Listeria cells were released into the environment at two different cell numbers and under two airflow conditions. Trypticase soy agar (TSA) plates and oven-roasted breasts of chicken and turkey were placed in the chamber to monitor Listeria cell numbers deposited from aerosols. A similar experimental design was used in the pilot plant study; however, only L. innocua was used. Results showed that L. monocytogenes and L. innocua survived equally well on chicken and turkey breast meats and TSA plates. No-fan and continuous fan applications, which affected airflow, had no significant effect on settling rates of aerosolized L. monocytogenes and L. innocua in the bioaerosol chamber or L. innocua in the pilot plant study. Listeriae cell numbers in the air decreased rapidly during the first 1.5 h following release, with few to no listeriae detected in the air at 3 h. Aerosol particles with diameters of 1 and 2 microM correlated directly with the number of Listeria cells in the aerosol but not with particles that were 0.3, 0.5, and 5 microM in diameter. Results indicate that L. innocua can be used as a surrogate for L. monocytogenes in an aerosol study.

A novel method for assessing the role of air in the microbiological contamination of poultry carcasses

This paper describes a novel method of measuring the contamination of raw foods with airborne bacteria during primary processing. To demonstrate the approach, this study aimed to quantify the role of airborne bacteria in the contamination of broiler chicken carcasses undergoing processing in an evisceration room. Settle plates and broiler carcasses were exposed to the evisceration room air or to ultra-clean air provided by a high efficiency particulate air (HEPA) unit located within the room. The use of ultra-clean air reduced the total aerobic counts on horizontal settle plates by 68-fold, and on vertical settle plates by 14-fold. The use of ultra-clean air had no significant effect on the total aerobic counts on carcasses as measured by sponging (3.5 log(10) CFU cm(-2)) or skin excision (4.0 log(10) CFU cm(-2)). The novel approach was able to show that the carcasses entering the room were so heavily contaminated that the airborne bacteria in the evisceration room contributed less than 1% of the total numbers of bacteria on the carcasses.

Transmission ofCampylobacterspp. in a poultry slaughterhouse and genetic characterisation of the isolates by pulsed-field gel electrophoresis

1. Contamination of retail products with Campylobacter spp. during the slaughter of poultry is a well-known problem of product hygiene. Mechanical evisceration often leads to intestinal rupture and discharge of gut contents, which can contain zoonotic and human pathogens. Processes along the slaughter line cause aerosols and airborne droplets, containing bacterial loads. 2. To estimate the possible transmission routes of intestinal Campylobacter, 36 measurements of the bioaerosol (Andersen sampler and SKC BioSampler), 30 cloacal (of three flocks), 10 equipment and 4 sedimentation samples were tested for the presence of Campylobacter species. 3. The results imply that, in addition to contaminated equipment, which was Campylobacter-positive in 80% of cases, aerosols with peak values of 4.0 x 10(4) (test series 1) and 1.4 x 10(4) (test series 2) CFU/m3 also provide a potential vector for horizontal transmission. 4. To explore the genetic similarities of isolates from different origins, 18 isolates recovered from air, 26 cloacal, 8 equipment and 4 sedimentation isolates were analysed by pulsed-field gel electrophoresis (PFGE), using the restriction enzymes Sma I and Sal I. The similarity of cloacal isolates with isolates from equipment, air and sediment, suggest that the contamination is of intestinal origin. 5. There were direct links between Campylobacter-positive flocks and the presence of the same strains in the aerosol of the slaughter hall. Air as a potential source for microbial transmission must be taken into account.

Microbial Composition in Bioaerosols of a High-Throughput Chicken-Slaughtering Facility

The microbial composition of the air in various areas of a high-throughput chicken-slaughtering facility was investigated. Over a 4-mo period, 6 processing areas were sampled, and the influence of environmental factors was monitored. The highest counts of microorganisms were recorded in the initial stages of processing, comprising the receiving-killing and defeathering areas, whereas counts decreased toward the evisceration, air-chilling, packaging, and dispatch areas. Maximum microbial counts were as follows: coliforms, 4.9 x 10(3) cfu/m(3); Escherichia coli 3.4 x 10(3) cfu/m(3); Bacillus cereus, 5.0 x 10(4) cfu/m(3); Staphylococcus aureus, 1.6 x 10(4) cfu/m(3); Pseudomonas aeruginosa, 7.0 x 10(4) cfu/m(3); presumptive Salmonella spp., 1.5 x 10(4) cfu/m(3); Listeria monocytogenes, 1.6 x 10(4) cfu/m(3); and fungi, 1.4 x 10(4) cfu/m(3). Higher counts of airborne microorganisms found in the receiving-killing and defeathering areas indicate the importance of controlling microbial levels before processing to prevent the spread of organisms downstream. This should limit the risk of carrying over contaminants from areas known to generate high counts to areas where the final food product is exposed to air and surface contamination.

Genotyping of Campylobacter jejuni from Broiler Carcasses and Slaughterhouse Environment by Amplified Fragment Length Polymorphism

We examined the occurrence and diversity of Campylobacter jejuni on broiler carcasses during slaughter of an infected flock and in the slaughterhouse environment during slaughter and postdisinfection before a new production run. During the slaughter of a known C. jejuni infected broiler flock, samples were taken from broiler carcasses at 7 different stages during the process. Thirty-seven sites in the slaughterhouse environment were sampled both during process and postdisinfection. The samples were analyzed for C. jejuni, and genetic fingerprinting was performed using amplified fragment length polymorphism. All carcass samples were positive. Of the environmental samples collected during slaughter, 89% were positive; 100% of those from the arrival, stunning, scalding, defeathering, and evisceration facilities and 67% of those from the cooling and sorting facilities. Postdisinfection, 41% of the samples were positive; 71% of those from the arrival and stunning area, 60% of those from the scalding and defeathering area, and 20% of those from the evisceration, cooling, and sorting area. The C. jejuni isolates (n = 60) recovered were grouped into 4 different amplified fragment length polymorphism clones with a similarity index of 95% or greater. All isolates obtained from the flock and 94% of the isolates obtained from the environment during slaughtering belonged to clone A, whereas 1 environmental isolate belonged to each of the clones B and C. Isolates from clones A, B, and D were present postdisinfection. Only clone B was detected on flocks slaughtered during the previous week. The high level and continuous presence of Campylobacter in the environment constitutes a risk for transmission to negative carcasses. In Norway, where above 96% of the broiler flocks are Campylobacter-negative, this aspect is of special importance. The ability of Campylobacter to remain in the slaughterhouse environment through washing and disinfection is associated with constructional conditions of equipment and buildings, complicating cleaning and providing sufficient moisture. To reduce the probability of the workers acquiring campylobacteriosis, precautions should be taken when slaughtering Campylobacter-positive flocks.

Food-associated bacteria in bioaerosols of delicatessens

Air constituency of the delicatessen sections of a retail group was assessed for the presence and distribution of bioaerosols and the correlation with physical parameters. Total viable counts were determined and the total coliforms, Escherichia coli, other members of the Enterobacteriaceae and Staphylococcus aureus were enumerated. These counts were relatively low, with the average total viable counts 1.34x102 cfu . m-3, Enterobacteriaceae 2.6x10 cfu . m-3 and S. aureus 2.2x10 cfu . m-3. Small numbers of total coliforms were detected and E. coli was not present at all. The distribution of Enterobacteriaceae differed significantly between three groups of visitor numbers and the total viable counts differed between two types of ventilation. The risk of infection should not be disregarded as a result of finding these organisms only in small numbers and could be a starting point in the prevention of food contamination, by regulating mechanisms to effectively minimize bioaerosols counts of enteric bacteria.

Distribution of airborne microorganisms in commercial pork slaughter processes

The objective of this research was to determine the prevalence and distribution of airborne bacterial contamination, with particular reference to Escherichia coli and Salmonella, at a number of stages in a pork slaughtering plant. Air samples (impaction and sedimentation) were recovered from seven locations before and during operations in a commercial pork processing plant. Aerobic mesophilic bacteria, E. coli counts and the incidence of Salmonella in the air were determined. Most sample locations which provided high impaction counts also provided high sedimentation counts. Before commencement of operations, there were no significant differences in aerobic mesophilic bacteria obtained from the sample locations. However, within 2 h of the commencement of operations, aerobic mesophilic bacteria in the wet room (3.14 log10 cfu/m3) were significantly higher (P < 0.05) than those in the clean room (2.66 log10 cfu/m3) and chiller (2.34 log10 cfu/m3). By the afternoon, similar aerobic mesophilic bacteria counts were recovered in the wet and clean rooms, although counts in both of these areas were significantly higher (P > 0.05) than in the chiller. In general there were no significant differences in E. coli counts between rooms (wet room, clean room and chiller) and these did not increase during the production day. Salmonella were detected at the locations of the dehairing and evisceration operations. Aerobic mesophilic bacteria in the air within the abattoir increased as production proceeded. In addition the air within the abattoir contained organisms such as Salmonella and E. coli. Positive correlations (P < 0.05-P < 0.001) between impaction and sedimentation samples were found suggesting that air may be an important source of carcass contamination.

Application of distilled white vinegar in the cloaca to counter the increase in Campylobacter numbers on broiler skin during feather removal

Because of the escape of highly contaminated gut contents from the cloaca of positive carcasses, Campylobacter numbers recovered from broiler carcass skin samples increase during automated feather removal. Vinegar is known to have antimicrobial action. The objective of this study was to determine the effect of vinegar placed in the cloaca prior to feather removal on the numbers of Campylobacter recovered from broiler breast skin. Broilers were stunned, killed, and bled in a pilot processing plant. Vinegar was placed in the colons of the chickens prior to scalding. Carcasses were scalded, and Campylobacter numbers were determined on breast skin before and after passage through a commercial-style feather-picking machine. Campylobacter numbers recovered from the breast skin of untreated control carcasses increased during feather removal from 1.3 log CFU per sample prior to defeathering to 4.2 log afterward. Placement of water in the colon before scalding had no effect on Campylobacter numbers. Campylobacter numbers recovered from the breast skin of carcasses treated with vinegar also increased during defeathering but to a significantly lesser extent. Treated carcasses experienced only a 1-log increase from 1.6 log CFU per sample before feather removal to 2.6 log CFU per sample afterward. Application of an effective food-grade antimicrobial in the colon prior to scald can limit the increase in Campylobacter contamination of broiler carcasses during defeathering.

Evaluation of Culture Media for Detecting Airborne Salmonella Enteritidis Collected with an Electrostatic Sampling Device from the Environment of Experimentally Infected Laying Hens

Detection of Salmonella enteritidis in the environment of commercial laying hens is critical for reducing the production of contaminated eggs by infected flocks. In the present study, an inexpensive and portable electrostatic air sampling device was used to collect S. enteritidis in rooms containing experimentally infected laying hens. After hens were orally inoculated with a phage type 13a S. enteritidis strain and housed in individual cages, air samples were collected 3 times each week with electrostatic devices onto plates of 6 types of culture media (brilliant green agar, modified lysine iron agar, modified semisolid Rappaport-Vassiliadis agar, Rambach agar, XLD agar, and XLT4 agar). Air sampling plates were incubated at 37 degrees C, examined visually for presumptive identification of typical S. enteritidis colonies and then subjected to confirmatory enrichment culturing. Air samples (collected using all 6 culture media) were positive for S. enteritidis for 3 wk postinoculation. Because visual determination of the presence or absence of typical S. enteritidis colonies on air sampling plates was not consistently confirmed by enrichment culturing, the postenrichment results were used for comparing sampling strategies. The frequency of positive air sampling results using brilliant green agar (66.7% overall) was significantly greater than was obtained using most other media. A combination of several plating media (brilliant green agar, modified lysine iron agar, and XLT4 agar) allowed detection of airborne S. enteritidis at an overall frequency of 83.3% over the 3 wk of sampling. When used with appropriate culture media, electrostatic collection of airborne S. enteritidis can provide a sensitive alternative to traditional methods for detecting this pathogen in the environment of laying flocks.

Detection of Airborne Salmonella enteritidis in the Environment of Experimentally Infected Laying Hens by an Electrostatic Sampling Device

Bacteriologic culturing of environmental samples taken from sources such as manure pits and egg belts has been the principal screening tool in programs for identifying commercial laying flocks that have been exposed to Salmonella enteritidis and are thus at risk to produce contaminated eggs. Because airborne dust and aerosols can carry bacteria, air sampling offers a potentially efficient and inexpensive alternative for detecting S. enteritidis in poultry house environments. In the present study, an electrostatic air sampling device was applied to detect S. enteritidis in a room containing experimentally infected, caged laying hens. After oral inoculation of hens with a phage type 13a S. enteritidis strain, air samples were collected onto agar plates with the electrostatic sampling device, an impaction air sampler, and by passive exposure to the settling of aerosols and dust. Even though the floor of the room was cleaned once per week (removing most manure, dust, and feathers), air samples were positive for S. enteritidis for up to 4 wk postinoculation. On the basis of both the number of S. enteritidis colonies observed on incubated agar plates and the frequency of positive results, the efficiency of the electrostatic device was significantly greater than that of the passive exposure plates (especially at short collection intervals) and was similar to that of the far more expensive impaction sampler. The electrostatic device, used for a 3-hr sampling interval, detected airborne S. enteritidis on 75% of agar plates over the 4 wk of the study.

Presence of Campylobacter inthe respiratory tract of broiler carcasses before and after commercial scalding

Campylobacter could be detected in the thoraco-abdominal cavity of broiler carcasses even if they were carefully eviscerated by hand with no evidence of intestinal rupture or leakage. If Campylobacter is present in the air sacs, which are unavoidably torn during evisceration, it could contaminate the thoraco-abdominal cavity of the eviscerated carcass. This study was done to determine if Campylobacter contamination is present in the respiratory tract of broilers prior to evisceration. Whole carcass rinses and respiratory tract washes were done on broiler carcasses collected at a commercial processing plant just before and just after scalding. Samples were cultured for presence and numbers of Campylobacter, Escherichia coli, coliforms, and total aerobic bacteria. Campylobacter isolates were subtyped by sequencing the short variable region of the flaA gene. The same subtypes of Campylobacter were detected in whole carcass rinse samples as in respiratory tract wash samples from individual broilers. Furthermore, the same numbers and subtypes of Campylobacter were recovered from respiratory tracts of carcasses collected before scalding and those collected after scalding. However, respiratory tracts of carcasses after scalding had higher numbers of E. coli, coliforms, and total aerobic bacteria than those tested before scalding. Although some bacterial counts were higher in the respiratory tracts of carcasses after scalding, Campylobacter counts were not. It appears that Campylobacter is present in the respiratory tracts of broilers as they enter processing, and contamination may be due to airborne bacteria during production or transport.

Campylobacter spp in human, chickens, pigs and their antimicrobial resistance

Campylobacter spp. have been identified as etiologic agents in outbreaks and sporadic cases of gastroenteritis in developed countries. In developing countries, most reported Campylobacter infections are in children. Previously reported prevalences of Campylobacter spp. in children in Southeast Asia range from 2.9% to 15%. The frequency and pattern of occurrence of Campylobacter spp. differ between developed and developing countries, especially in the number of cases reported in adults and the presence of any seasonal patterns in occurrence. Although the severity of Campylobacter infection in adults was different between developed and developing countries, the clinical symptoms of infection in adults resulting from infection in developing countries was similar to those in developed countries. Many different animal species maintain Campylobacter spp. with no clinical signs. There do not appear to be significantly different colonization rates of Campylobacter in food animals between developed and developing countries. The role of C. jejuni as a primary pathogen in farm animals is uncertain. C. jejuni can be found in feces of diarrheic and healthy calves and piglets. Campylobacter with resistance to antimicrobial agents have been reported in both developed and developing countries, and the situation seems to deteriorate more rapidly in developing countries, where there is widespread and uncontrolled use of antibiotics resistance was observed at high levels in food animals in both developed and developing countries. Studies suggested an association between antimicrobial use in food animals and the development of resistance in human isolates in developed countries.