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Airborne bacteria and mold in slaughterhouse facilities

Contamination of meat products by microorganisms such as airborne bacteria and mold is a major economic problem in the meat industry. In the past it was thought that food products were contaminated when they came in contact with contaminated surfaces, but now it is known that additional product contamination occurs from contact with airborne bacteria.

There are several pathways in which pathogenic airborne bacteria and spoilage organisms can be introduced to products. It is known that contamination can occur at various points during the slaughter process, cold storage, and processing of meat animals.

One potential source of contamination that is often overlooked is air. Air is a potential source of contamination by pathogenic and spoilage organisms in meat processing plants and should be considered a processing critical control point.

Unsanitary environmental conditions in food processing plants can occur due to suspended bacterial particles in the air. These biological particles are microscopic, with a diameter of 0.5 to 50 μm and are suspended in the air as an aerosol. Airborne contaminants are also known as bioaerosols and include bacteria, fungi, viruses and pollen. These may be present in the air as solid (dust) or as liquid (condensation and water).

An aerosol is a two-phase system of gaseous phase (air) and particulate matter (dust, pathogens), thus making an important bacterial vehicle. Pathogenic bacteria attach to dust particles and condensation, and travel around the processing facility. This contaminated air comes in contact with food products, containers, equipment and other food contact surfaces during processing.

It is impossible to keep airborne bacteria, yeast and mold in food processing areas at a zero level. Some of the major sources of contamination in food processing facilities are wastewater, rinse water and spilled product that become aerosolized. Airborne bacteria, yeast and mold are generated in processing facilities by heating, ventilation and air conditioning systems (HVAC).

These systems contribute airborne microorganisms under normal operation because they provide fertile areas for growth due to moisture. Worker activity, equipment operation, sink and floor drains, and high pressure spraying are also major sources of bioaerosols. Worker activity, talking, sneezing and coughing create dust particles and air disturbances creating airborne microorganisms. The workers’ contribution of airborne bacteria depends on their health, condition of clothing, hygiene and location in processing facility.

Equipment operation contributes to variations in microorganism levels. Airborne bacteria also increase with the use of conveyor systems which cause bacterial aerosols that adhere to conveyor surfaces. Barriers like walls and doors are used to separate clean and unclean areas. Sink and floor drains can harbor microorganisms because they are humid and contain nutrients from wastewater which provide a fertile growth environment.

Flooding of drains causes microorganisms on the surface to become aerosolized and air disperses them, causing increased levels of aerosolized bacteria in the food processing facility. High pressure spraying also causes an increased level of aerosolized bacteria after spraying.

Intense husbandry practices and long term residence of cattle in feedlots and pens provide great opportunity for microorganisms to affix to hoofs and hides. Animals entering a slaughter facility have a vast population of aerobic microorganisms on their hide, hooves and inside their intestinal tract, while the internal surface of carcasses is generally considered to be sterile.

It is generally agreed that the majority of microorganisms on a dressed red meat carcass are directly transferred from the contaminated hide and ruptured gastrointestinal tract. Bacterial transfer to the carcass also occurs by aerosols, dust generation, workers hands, and the contact of the hide with the exposed tissue. The majority of carcass contamination occurs during slaughtering and dressing procedures.

Research regarding airborne bacteria contamination levels in meat processing facilities indicates airborne microbes are a potential source of microbiological contamination in various meat products.

The majority of the Gram negative airborne bacteria usually isolated during slaughtering are from the Enterobacteriaceae and Pseudomonadaceae family. Most of the Gram positive airborne bacteria isolated during slaughtering are Staphylococcus, Microbacterium, Bacillus and Micrococcus species.

The potentially pathogenic microorganisms usually found in the air sampling areas and on the carcasses are Escherichia coli, Salmonella spp., Shigella spp., Staphylococcus spp. and Bacillus spp. and the spoilage microorganisms are Moraxella spp., Pseudomonas spp., Acinetobacter spp., Brochothrix spp. and Micrococcus spp. According to the research, the isolation of various organisms, including Staphylococcus, Escherichia, and Salmonella species, from both air samples and carcass swabs during slaughtering supports the theory that bioaerosols transport bacteria and contribute to the contamination of pork and beef carcasses.

There are various methods for the detection of viable airborne bacteria and other microorganisms. The quantitative determination of airborne microorganisms is possible by sedimentation, impaction on solid surfaces, impingement in liquids, filtration, centrifugation, electrostatic precipitation and thermal precipitation.

Swabbing of equipment is typically used to determine the sanitation level of food processing plants. This method does not always provide an effective enumeration of airborne contaminants.

Air sampling is more effective because it collects aerosols settled on equipment and food contact surfaces. Through air sampling, food processing facilities can identify airborne contamination due to air contact with food products. Ideally, an air sampler would be able to collect all of the viable microorganisms per unit volume of air, but this is not possible because not all airborne cells can be physically separated from the air without killing them during sampling.

The majority of air samplers used in the food industry use impaction as the method for collecting bioaerosols. Impaction methods use the inertia of particles to separate them from the air currents. Impactors collect airborne microorganisms onto an agar surface or an adhesive coated surface with the use of a vacuum. An impactor consists of an air jet that is directed over the impaction surface causing the particle to collide and stick to the surface.

There are two types of impactors: slit (i.e. STA) or sieve (i.e. Andersen sampler) samplers. A slit sampler is cylindrical in shape and has a tapered slit tube that creates a jet stream when an air samples is pulled by a vacuum. The air sample is collected onto an agar plate which is rotating on a turn table to create an even distribution of particles. A slit sampler requires a vacuum to draw a constant flow rate of usually 28.3 liters per minute.

Sieve samplers function by drawing air (i.e. 28.3 l/min) through a metal plate with many small holes. Air particles impact on the agar surface which is a few millimeters below the metal sieve.

Impaction methods obtain higher recovery rates than other air sampling methods and are used when bioaerosol levels are expected to be low. This method results in a low sampling stress and after collection no further manipulation is needed because particles are on agar plates. Impactors possess relatively high sampling efficiencies, are rugged and simple to operate.

As per the research studies, it is important to control contaminants in the air of slaughtering facilities. Airborne contaminants cause human illness due to ingestion of contaminated foods and also reduce product shelf life resulting in an economic loss. According to the Food and Drug Administration (FDA), the food industry must reduce product contamination by reducing airborne microorganisms.

If you are considering testing for the airborne bacteria or mould in your slaughterhouse facility, contacting Mold & Bacteria Consulting Laboratories would be a good choice. Our analysts are trained on air sampling methods and detection of airborne bacteria and moulds. You can call our Ontario, Mississauga office at 905-290-9101 or the British Columbia, Burnaby office at 604-435-6555 and see how we can help.

References:

G.H.C.Sutton. 2004. Enumeration of Total Airborne Bacteria, Yeast and Mold Contaminants and Identification of Escherichia coli O157:H7, Listeria Spp., Salmonella Spp., and Staphylococcus Spp. in a Beef and Pork Slaughter Facility. University of Florida: 1-141.

M.Dobeic, E.Kenda, J.Mičunovič, I.Zdovc. 2011. Airborne Listeria spp. in the Red Meat Processing Industry, Czech J.Food Sci., 29 (4): 441-447.

C.J.Cundith, C.R.Kerth, W.R.Jones, T.A.McCaskey, D.L.Kuhlers. 2002. Air-cleaning Systems Effectiveness for Control of Airborne Microbes in a Meat-processing Plant. Food Microbiology and Safety: 1-5.

T.M.Rahkio, H.J.Korkeala. 1997. Airborne Bacteria and Carcass Contamination in Slaughterhouses. J. Food Prot. 60 (1): 38-42.

Airborne bacteria and mould in paper production facilities

Airborne bacteria and mould can reach very high levels in the pulp and paper manufacturing plants.

Process water contains sugars, starch, and other components that support and promote the growth of bacteria and, certain yeasts and moulds.

Interestingly, the non-biological and biological waste present in wastewater from pulp and paper production facilities can be treated using specific bacteria and certain moulds. This process known as biological wastewater treatment works by using specialized microorganisms (bacteria and mould) that naturally use the waste as food sources.

The type of microorganisms chosen for remediation must be carefully selected by examining the toxins present in the wastewater. Examples of bacteria used to treat wastewater include Pseudomonas putida, Citrobacter sp., and Enterobacter sp. Examples of fungi used to treat wastewater include Pencillium sp., Trametes versicolor, Pycnoporus sanguineus, Pleurotus ostreatus, and Phanerochaete chrysosporium.

Before one can understand where airborne bacteria and mould are produced during the process of paper-making, however it is important to understand the process. Figure 1 is an overview of the paper-making process and, Figure 2 expands on the steps of the paper-making machine.

Depending on the type of pulping process used for paper making, certain toxic chemicals are generated. In the early 1900s, sulphite pulping was most dominantly used in Canada until it was replaced by the Kraft process. Unfortunately, the Kraft process is still a main source for toxic pulp mill effluents and is now being challenged by chemithermo-mechanical pulping (CTMP) which usually meets pollution effluent standards.

Biosolids or “sludge” are a major waste product produced in pulp and paper mills. Biosolids provide ideal conditions for the presence and growth of microorganisms, some of which may be pathogenic. Biosolids become airborne through the release of dust and water droplets creating bioaerosols. Bioaerosols are airborne particles that consist of bacteria, viruses and moulds or, metabolites, toxins or fragments from the microorganisms.

Inhalation of airborne bacteria and mould by individuals who suffer from allergies, are immuno-compromised, young children, pregnant women, or the elderly can lead to inflammation, respiratory allergies and sometimes infection. The high speed of the paper making machine (up to 2000 m/min) often creates aerosolization of process water. Debarking drums also splash and aerosolize water.

A type of bacteria often found in pulp and paper biosolids is Klebsiella pneumonia. These bacteria do not typically infect healthy individuals, however those with weakened immune systems as described above can suffer from infection. The most common form of infection caused by Klebsiella is pneumonia however, Klebsiella can also cause urinary tract infection, cholecystitis, diarrhea, upper respiratory tract infection, wound infection, meningitis, bacteremia, to name a few.

Klebsiella pneumonia, Acinetobacter sp. and Enterobacter sp., which are examples of Gram-negative bacteria that are often found in debarker water and process water. These Gram-negative bacteria and yeasts are able to thrive in debarkers because of favourable conditions including low temperature, high humidity and lack of biocides. Refer to Figures 1 and 2 for areas within the paper-making process that are common sources of airborne bacteria and mould.

In one study performed by Sillanpa et. al (1985) the nasal cavities of workers in three paper and board mills were examined. The nasal cavities of many workers working with the debarkers were contaminated with Klebsiella pneumoniae, other coliforms, yeasts or moulds. However, the host defenses of the workers seemed to protect them from illness.

Table 1: Bioaerosol concentrations measured in paper mills

Workplace	Total bacteria(CFU/m³)a	Gram negativebacteria(CFU/m³)	ThermophilicActinomycetes(CFU/m³)	Molds(CFU/m³)
Outdoors	10²	10¹	10¹	10³
Paper mill effluents	10⁴	10³	10¹	10⁴
Papermill	10⁶	10^2-3	–	10³

*This table was derived from Bioaerosols in the Workplace: Evaluation, Control and Prevention Guide – Nicole Goyer, Jacques Lavoie, Louis Lazure, and Genevieve Marchand, (2001)

In order to control the growth of microbes in process water, biocides are regularly added. Even so, high numbers of bacteria (10⁶– 10⁸ growth units/mL) usually occur in various parts of the paper making process such as the head box or coated broke. The head box or flow box is the tank the delivers pulp onto the wire for paper making (refer to Figure 2). The coated broke consists of rejects of quality mixed paper with process water and then reused for paper making.

Table 2: Dominant bioaerosols in paper mills

SUBSTRATE	DOMINANT MOLDS
Paper	Aspergillus, Penicillium, Chaetomium, Acremonium, Beauveria, Cladosporium, Epicoccum, Papulospora, Phoma, Scopulariopsis, Ulocladium

*This table was derived from Bioaerosols in the Workplace: Evaluation, Control and Prevention Guide – Nicole Goyer, Jacques Lavoie, Louis Lazure, and Genevieve Marchand, (2001)

Sampling to test for airborne bacteria and mould is typically done by an Andersen pump with an impactor using nutrient media specific for total bacteria, Gram negative bacteria, total mold or the mold Aspergillus fumigatus. An example of the recommended sampling flow is 28.3 L/min for 1-5 minutes. (If you are interested in taking samples or renting a pump, you can contact us for help or to provide you with the equipment).

For more information about our mould or bacteria testing services, please contact Mold & Bacteria Consulting Laboratories. Please call our Ontario, Mississauga Office at 905-290-9101 or the British Columbia, Burnaby Office at 604-435-6555.

References:

Goyer N, Lavoie J. 2001. Identification of sources of chemical and bioaerosols emissions into the work environment during secondary treatment of pulp mill effluents. Tappi Journal. 24(2):2-13.

Goyer N, Lavoie J, Lazure L, Marchand G. (2001). Bioareosols in the Workplace: Evaluation, Control and Prevention Guide. Technical Giode T24, Montreal, IRSST, 72 pages. https://www.irsst.qc.ca/en/-irsst-publication-bioaerosols-in-the-workplace-evaluation-control-and-prevention-guide-t-24.html.

Murray, W. April 1992. Pulp and Paper: The Reduction of Toxic Effluents. Library of Parliament Research Branch. Ottawa, Canada: Canada Communication Group. http://publications.gc.ca/Collection-R/LoPBdP/BP/bp292-e.htm. Retrieved 2013-04-03.

Niemelä, SI, Väätänen P, Mentu J, Jokinen A, Jäppinen P, Sillanpää P. (1985). Microbial Incidence in Upper Respiratory Tracts of Workers in the Paper Industry. Appl. Environ. Microbiol. 50(1):163-168.

Pokhrel, D, Viraraghavan, T. 2004. Treatment of pulp and paper mill wastewater-a review. Total Science of the Environment. 333:37-58.

Forcier, F. September 2002. Biosolids and Bioaerosols: The Current Situation. Prepared for Quebec Ministry of Environment.

Thompson G, Swain J, Kay M, Froster CF. 2001. The treatment of pulp and paper mill effluent: a review. Bioresour Technol. 77(3):275-286.

Velema, G. 2004. Management and benefits of pulp and paper mill residuals at Domtar Cornwall. Pulp & Paper Canada.105(7):150-156.

MBL Among The CDC ELITE Certified Labs in Legionella Testing

Mold & Bacteria Consulting Laboratories (MBL) has certification in the analysis of Legionella bacteria by the prestigious Environmental Legionella Isolation Techniques Evaluation (ELITE) program of the US Centers for Diseases Control and Prevention (CDC). You can view our current Certificate of Proficiency for Legionella Testing.

MBL is one of the only 3 Canadian independent laboratories having this industry-leading certification. MBL is also accredited by the Canadian Association For Laboratory Accreditation (CALA) for analysis of fungi and bacteria including Legionella.

Colonies of Legionella on selective media BCYE — Legionella Colonies

Legionella is a type of bacteria that is found primarily in warm or hot water environments (35- 37°C). These bacteria can cause Legionellosis. Legionellosis comes in two forms, Pontiac fever, the lesser of the forms, and also Legionnaires’ disease which is a more severe illness with a deadly type of pneumonia. Thousands of people get Legionnaires’ Disease in the United States each year.

The Centers for Disease Control and Prevention (CDC) reports between 8,000 and 18,000 cases of Legionnaires’ disease annually, but it also estimates that more than 90 percent of cases go unreported. Of the approximated 2.4 million cases of pneumonia that are diagnosed in hospital patients each year in the United States.

About 18,000 cases are confirmed as Legionnaires’ Disease and up to 600,000 cases of Legionnaires’ Disease are misdiagnosed as pneumonia because the hospitals do not perform the tests for Legionella.

Legionella bacteria were first identified as cause of pneumonia in 1976, after an outbreak of pneumonia among attendants of an American Legion convention in Philadelphia, Pennsylvania . Following the outbreak further investigation into Legionella was conducted and it was discovered that earlier unexplained pneumonia outbreaks could have been caused by these bacteria. The earliest cases of Legionnaires’ disease were shown to have occurred in 1965.

Legionella is acquired exclusively through inhalation of contaminated water droplets. The number of bacteria cells required to induce infection is not known, but varies according to age, general health, and other predisposing factors. However, the organisms must be present in sufficiently high concentration and must be suspended in aerosols between 3 and 5 microns in diameter.

Though it is possible that healthy people can be infected, people with compromised immune systems, respiratory illnesses, and cancer are much more likely to become sick. It is estimated that 10 to 20 percent of those infected die, but in individuals with compromised immune systems, the fatality rate is likely to be much higher.

Legionella identification is traditionally performed by growing the bacteria in special nutrient media (buffered charcoal yeast extract (BCYE) agar) that encourage the growth of Legionella and discourage the growth of other bacteria. This test is considered the “gold standard” for diagnosing an infection caused by Legionella bacteria. A positive culture may be determined in about 48 to 72 hours. Negative cultures are held for at least 14 days before a final result is reported.

Use of Biocides in Controlling Legionella

Legionella and other bacteria thrive in biofilm, which is impervious to most biocides. From time to time, pieces of biofilm break off and make their way out of the system through a faucet or showerhead. The microscopic, pathogen-rich particles aerosolize and can be inhaled. It is estimated that 70 percent of hospital water systems are likely colonized by Legionella bacteria. The immune-compromised are most susceptible to Legionnaires’ and other diseases caused by waterborne pathogens. Legionnaires’ disease has a reported mortality rate of up to 30%.

Legionnaires’ Disease and Symptoms

Legionnaires’ disease (LEE-juh-nares) is a form of pneumonia caused by the bacterium Legionella pneumophila. A mild form of the disease is called Pontiac fever. Unlike Legionnaires’ disease, which affects only a small percentage of people who are exposed, Pontiac fever will affect approximately 90 percent of those exposed.

In addition, the time between exposure to the organism and appearance of the disease is generally shorter for Pontiac fever than for Legionnaires’ disease. Symptoms of Pontiac fever can appear within one to three days after exposure.

Legionnaires’ disease may occur sporadically in the form of community acquired pneumonia and in epidemics.

It is a respiratory infection acquired after inhaling Legionella pneumophila from mist from water sources such as whirlpool baths, showers, and cooling towers that are contaminated with Legionella bacteria.

The disease may be characterized by general malaise, chills and fever. People of all ages can get Legionnaires’ disease, but it primarily affects people with weakened or compromised immune systems, including those who are over age 65, those with lung disease and smokers and generally men more than women. Some people can be infected with the Legionella bacteria and have only mild symptoms or no illness at all.

Legionnaires’ disease is most frequently associated with persons with weak immune system. The disease has been associated with domestic hot-water systems in a number of outbreaks. Legionella can also proliferate in poorly maintained whirlpools, spa pools and associated equipment. Naturally, Legionella bacteria live in fresh water and are often found in hot tubs, air conditioning cooling units and fountains.

Since Legionnaires’ disease can have symptoms similar to those of many other forms of pneumonia, it can be hard to diagnose at first. Legionnaires’ disease is a serious illness and deaths may occur in approximately 10-15% of otherwise healthy individuals. Legionnaires’ disease is not contagious and cannot be transmitted from one person to another.

The disease was named after its discovery in a group of people attending an American Legion convention in 1976. Disease may develop from several days to two weeks after exposure. Symptoms typically disappear within two to five days. Disease is treatable with antibiotics. Legionnaires, disease is also more common in the summer months.

Legionellosis is the term that collectively describes infections caused by members of the Legionellaceae family.

Legionella can grow to dangerous levels in systems that store water, including ornamental water features. Water is the major environmental reservoir for Legionella. Legionella bacteria are protected against standard water disinfection techniques, by their symbiotic relations with later microorganisms (protozoa). Legionella is more resistant to chlorine and microbial biocides than other microorganisms.

In summary, Legionnaires’ disease is caused by Legionella bacteria. Legionella lives naturally in rivers, lakes, and reservoirs but can also be found in cooling towers and domestic water systems. Legionnaires’ disease can be contracted by inhaling in droplets of water containing the Legionella bacterium from water sources where there have been poor maintenance, problems with controlling the temperature of the water or where water has remained stagnant for some time.

For Legionella testing, contact Mold & Bacteria Consulting Laboratories either in British Columbia at 604-435-6555 or in Ontario at 905-290-9101.

Expanded Recall for Foaming Hand Soap due to Pseudomonas aeruginosa Contamination

Recently there was a recall of Antimicrobial Foaming Hand Soap (Triclosan 0.3%) due to contamination with Pseudomonas aeruginosa. As a precautionary measure, the recall was extended to 21 lots of the product X3 Clean Alcohol-Free Foaming Hand Sanitizer (Benzalkonium chloride 0.13%).

Pseudomonas aeruginosa was discovered in 1882 and was subsequently found to cause a variety of human infections. It is a common bacterium found in a wide range of environments. It infects nematodes, insects, plants, and amoeba in the laboratory. It is also found in water and soil.

In humans, Pseudomonas aeruginosa is distinguished as an opportunistic pathogen, causing a wide range of infections, including deadly pneumonia in immuno-compromised individuals such as cancer patients receiving chemotherapy, burn patients, those on ventilators or with catheters, AIDS patients, and others. It is one of the most common nosocomial pathogens in intensive care units (ICUs). Individuals in intensive care units can develop ventilator-associated pneumonia and/or sepsis as a result of Pseudomonas aeruginosa infection.

According to the CDC, the overall incidence of Pseudomonas aeruginosa infections in US hospitals averages about 0.4 percent or 4 per 1000 discharges. It is the fourth most commonly isolated nosocomial pathogen accounting for 10.1 percent of all hospital acquired infections.

Within the hospital, Pseudomonas aeruginosa has numerous reservoirs such disinfectants, respiratory equipment, food, sinks, taps, and mops. This organism is often reintroduced into the hospital environment on fruits, plants, vegetables, as well by visitors and patients transferred from other facilities.

Spread of Pseudomonas aeruginosa occurs from patient to patient on the hands of hospital personnel, by direct patient contact with contaminated reservoirs, and by the ingestion of contaminated foods and water.

Pseudomonas aeruginosa has shown resistance to multiple antibiotics and consequently has joined the ranks of ‘super bugs’. It shows decreased susceptibility to most antibiotics due to low outer membrane permeability coupled to adaptive mechanisms.

Pseudomonas aeruginosa as cause of eye infection

Contact lenses, particularly the extended wear variety, render wearers vulnerable to eye infections from Pseudomonas aeruginosa . These infections can cause severe damage, including blindness.

Pseudomonas aeruginosa as cause of respiratory infection

An outbreak of seven cases of Pseudomonas aeruginosa respiratory tract infection and nine instances of respiratory tract colonization has been reported. This infection was inked to contaminated ultrasound gel.

Lower respiratory tract infection with Pseudomonas aeruginosa occurs in most people with cystic fibrosis. Once chronic infection is established, Pseudomonas aeruginosa is virtually impossible to eradicate and is associated with increased mortality and morbidity. Early infection may be easier to eradicate.

If you are concerned about Pseudomonas, We can help! We can perform a presence/absence test to detect the bacteria. For more information about our Pseudomonas, other bacteria or mold testing services, please contact Mold & Bacteria Consulting Laboratories, please call our Ontario, Mississauga Office at 905-290-9101 or the British Columbia, Burnaby Office at 604-435-6555.

For more information on the recalled products, click on the links below.
http://www.winnipegfreepress.com/arts-and-life/life/health/recall-expanded-for-foaming-hand-soap-due-to-bacterial-contamination–174828881.html
http://www.hc-sc.gc.ca/ahc-asc/media/advisories-avis/_2012/2012_156-eng.php

Article edited and expanded by Dr Jackson Kung’u

Airborne bacteria and mold in slaughterhouse facilities

Airborne bacteria and mould in paper production facilities

MBL Among The CDC ELITE Certified Labs in Legionella Testing

Use of Biocides in Controlling Legionella

Legionnaires’ Disease and Symptoms

Expanded Recall for Foaming Hand Soap due to Pseudomonas aeruginosa Contamination

Pseudomonas aeruginosa as cause of eye infection

Pseudomonas aeruginosa as cause of respiratory infection

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