Accelerating the detection of yeast and mold in yogurt

By Jennifer Johnson

What was once an obscure foreign dairy product, Greek yogurt has exploded into a billion dollar business, and it is still growing!  Greek yogurt sales are 50% higher than at this time last year and represent more than one-third of all yogurt sold in the U.S. By comparison, in 2007 Greek yogurt accounted for only 1% of the total yogurt market.

As with regular yogurt, Greek yogurt is made from fermented milk that is soured and thickened by adding specific lactic acid-producing cultures. However, Greek yogurt is strained more times than traditional yogurt to remove more whey. As a result, Greek yogurt is thicker and has more protein than regular yogurt. The basic cultures or probiotics used to make yogurt are Lactobacillus bulgaricus and Streptococcus thermophilus and many additional probiotic organisms are often added which include Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium species, all of which may help to maintain the balance of bacteria needed to boost the immune system and promote a healthy digestive tract. According to the Obesity Action Coalition, yogurt is the number 1 natural source of probiotics eaten by Americans. The live microorganisms in Greek yogurt can help improve your digestive system, help your body absorb nutrients, and improve your health. Greek yogurt may also help ease gastrointestinal conditions like constipation, inflammatory bowel disease, lactose intolerance, and diarrhea.

It is this overabundance of helpful bacteria that can interfere with the detection of yeast and molds in Greek yogurt.

Yeast and Mold Testing in Yogurt

Undesirable microorganisms constitute the primary hazard to safety, quality, and wholesomeness of milk and dairy foods. Yogurt is susceptible to microbial contamination, especially by fungi which grow and reproduce in acidic environments containing oxygen.  In a study by Montagna et.al. (1998), a variety of differently manufactured yogurts from a variety of manufactures tested positive for fungi, of which 75% of the 7.2% positives were yeasts and 25% were molds with counts between 200 and >106 cfu/ml. Yogurts contaminated by fungi can have modified organoleptic characteristics. The most common molds found were Aspergillus and Penicillium and the most common yeast belonged to Candida, Cryptococcus, Rhodotorula species.

Traditional methods are slow, tedious, labor intensive, and often not suitable for assessing the quality and shelf-life of perishable dairy products. The emphasis on the programs based on HACCP (Hazard Analysis and Critical Control Points) for total quality management in the dairy industry and increased demand for microbiological surveillance of products, process, and environment, have led to increased interest in rapid methods and automation in microbiology. In the past few years rapid automated methods such as BioLumix and Soleris have been adopted to speed up time to results and automate and simplify the microbiologist tasks.

The BioLumix technology can make the microbiological testing simpler, faster, and automated, saving time, labor and money. 

The BioLumix test method for detection of yeast & molds involves a direct addition of the sample into ready to use vials and automated monitoring of the samples in the instrument. This simple method saves labor and disposables.  The yeast & mold assay is completed in 48 hours as compared to the 5 days required for the standard assay.

The ready–to-use vial comes with media that is pre-adjusted for pH, such that after the addition of the sample the appropriate pH for the growth of the microorganisms is attained. BioLumix has developed such a media that is custom made with a higher pH to accommodate the low pH of yogurt while still maintaining the capability to test as much as 1.0 gram of product directly in the vials. The addition of the supplement to the vial results in the elimination of background growth from lactic bacteria resulting in flat curves.

The initial work with yogurts containing high levels of probiotics showed that the probiotics caused false detection in the instrument due to the CO2 production by the Probiotic bacteria.  As shown in the picture below, the addition of a supplement containing inhibitors to prevented the growth of the probiotics in the vials and resulted in a clear detection of fungi, when present, and a clean flat curve when organisms are not present. 

This newly developed assay has a high sensitivity, being able to detect a few yeast or molds in a gram of sample, is easy to perform (less than one minute hands on time), and result in quick time to results. Many different flavors of various brands of yogurt were tested and none created a false positive result.  Store bought contaminated yogurt detected in the system as did all the samples inoculated with low levels of yeast or mold.

The BioLumix System is designed to accelerate product release with a simplified, automated approach. The system yields fast, accurate, real-time results while reducing costs and eliminates the time required for the assays to be completed.  The system offers real-time results of contaminated samples saving hours, possibly days.

BioLumix will streamline and simplify the microbiological procedures, save labor and create a paperless laboratory, while generating results that correlate well with plate count methodology.

If you are interested in participating a field trial with Neogen’s new test, please contact marketing.fs@neogen.com

 

Reference:
M.T. Montagna, R. Erroi, S. Sanapo, G. Caggiano, F. Bagordo, A. De Donno, Food products and fungal contamination. Note I. Preliminary investigation in commercial yoghurt. Journal of Preventative Medicine and Hygiene 39: 68-70. 1998

Come and See us at the IAFP in Indianapolis, IN August 3-6, 2014; Booth 610

The 2014 Annual International Association of Food Protection (IAFP): The IAFP meeting will provide attendees with information on current and emerging food safety issues, the latest science, innovative solutions to new and recurring problems. It also provides an opportunity to network with thousands of food safety professionals from around the globe. This meeting has grown over the years to become the leading food safety conference worldwide.
More than 2,800 scientists, from six continents, attend the IAFP Meeting. This event owes its reputation and success to the quantity, quality and diversity of each year’s program; the quality and relevance of exhibits sharing the latest in available technologies; leading experts speaking on a variety of timely topics.
All of us at BioLumix want to take this opportunity to invite you to our exhibit (booth #610) and show you what’s new at BioLumix. We continue to innovate, growing our assay repertoire and capabilities – allowing you to perform all required assays on raw ingredients and finished products, as well as test environmental samples and process water.
During the IAFP show, we will feature:
New Listeria vial: The vial helps detect Listeria in environmental swabs. The Listeria vial capitalizes on the ability of Listeria to hydrolyze esculin, which in the presence of ferric ions, results in the yellow broth turning black and a reduction of the absorbance. A Listeria detection obtained with the BioLumix system can be further verified using a simple and quick Rapid Listeria Immunostrip Test. There was 100% agreement between the BioLumix system and plate methodology when product swabs contained Listeria.
Enhanced B. cereus vial: Recently the inhibitory system of the B. cereus vial was enhanced to eliminate the detection of non-target organisms. It uses the CO2 sensor at the bottom of the vial. The new BC vial recovers well vegetative cells as well as spores. The method used is very simple; just pipette the diluted sample into the vial. The results are available in 24 hours or less.
Direct inoculation of products into vials: Many products can be introduced directly into the BioLumix test vial without the need of a dilution step. These include yogurts and sour cream, as well as milks. Complete coliform test results are obtained within 12 hours with one vial substituting for nine or more MPN (Most Probable Number) test tubes. Yeast and mold results are obtained in 48 hours rather than 5-7 days using plate methods.

The yogurt can be directly added (Figure 1) into BioLumix vials to measure growth of Coliforms or Yeast and Molds. Specialized high pH BioLumix vials can also be used for yogurt samples. When a low pH yogurt sample is added to the BioLumix high pH Coliform vial (CC), the pH conditions become near neutral. This ensures the yogurt manufacturer to be able to correctly test for coliforms using a direct (without dilution) sample of product. As much as 1 gram of product can be directly tested in each BioLumix test vial.

With automated monitoring of ready-to-use assay vials, along with automated data processing and archiving, the microbiologist’s job gets a lot easier with the same accurate results in less than half the time. Our innovative vial design prevents product interference even when directly testing products, such as yogurt and salad dressing. Come to our booth (#610) or contact us directly (734-984-3100) to learn more about the exciting new developments we are featuring at this year’s IAFP.

The BioLumix Advantage
• Vial design prevents product interference
• Automation and connectivity allows faster product release
• Real-time communication for immediate action
• Expedited results: most results in 12-18 hours; Yeast and mold assay in 48 hours
• Automated data archiving and audit trail
• Streamlined testing increases laboratory efficiencies
• Paperless laboratory: centralized test data automatically stored and protected
• Barcode capability for automated sample entry
• Environmental testing made easy

Free Product Trial
Give us your most difficult samples and we will test them for free. We will provide you with a detailed report which includes a side-by-side comparison to your current manual methodology. The data generated is strictly confidential and is only used to show the high correlation of results should your company decide to purchase.

We look forward to working with you and earning another satisfied customer!

Detection of psuedomonads in dairy and water samples using a quantatative one-step testing protocol in just one day

By Roger Brideau*
*Presented in part at the International Association of Food Preservation
‘IAFP’ Conference in Charlotte NC USA

dairy microbiology detection of psuedomonads Introduction- Pseudomonad organisms are a major cause of bacterial spoilage of pasteurized milk and dairy products due to post process contamination.  Early detection of Pseudomonad’s can be a predictor of product shelf-life as they are the predominant psychotropic bacteria present.  BioLumix has developed a rapid method for the detection of Pseudomonad’s in dairy products and the method is also applicable to their detection in process water.

Purpose- To evaluate the ability of the BioLumix system to detect Pseudomonad’s in dairy products, determine the speed to results, sensitivity, selectivity and ability to predict shelf-life.

Methods- the BioLumix system is an optical system that detects growth of Pseudomonad’s using a CO2 sensor in selective growth media.  The BioLumix system was directly compared to the plate count methodology for milk samples stored at refrigerated temperatures and held overnight at room temperatures (enriched).  Testing of water was also accomplished in side by side studies to show the capability of the BioLumix system for quantitation of Pseudomonads.

Results:  Growth of Pseudomonad’s in the BioLumix vial
Table of quantitation of Pseudomonads
A growth comparison was made for detection of each Pseudomonad in the BioLumix system using PSE-B vials and on CFC (Pseudomonas agar) spread plates.  Table 1 summarizes the growth of freshly diluted samples of organisms that were enriched in TSB during the prior 18-24 hrs.  The PSE-B vials are selective, as shown by not allowing growth of unrelated gram positive and gram negative bacteria, yeast or mold.  Four different species of Pseudomonad’s grew in the PSE-B vial and on CFC plates.

Milk Sample Testing
Commercial milk samples were tested upon arrival in the laboratory.  Five of twenty were positive for the presence of Pseudomonad’s using both PSE-B vials and CFC spread agar plates.  After storage for 3-7 days, twelve of twenty samples were positive for Pseudomonad’s including after enrichment at RT for 16-18 hrs.  Thus, refrigerated milk samples have varying incidence of Pseudomonad flora.

Dairy Microbiology Calibration dataMilk Calibration Curve
Organisms from milk samples that grew in PSE-B vials and on CFC plates were used to generate the Calibration Curve shown in Figure 1. These data suggest that low numbers (~10) of Pseudomonad’s should detect within 24 hrs in the PSE-B vial. The Calibration Curve can be embedded into the BioLumix software on the instrument and used to generate a read-out of cfu per gram of milk.  This enables quantitation of the milk sample for the presence of Pseudomonad’s before 24 hr; a distinct advantage over plate methodology taking 48-72 hours.

Dairy Microbiology detection time distributionDistribution of Data
In the dairy settings the goal is to separate a “good” sample that has a potential to maintain quality over a product’s shelf-life from a “bad: sample that will have a shorter shelf life. Criteria for separation between a “good” and “bad” product based upon the Pseudomonad’s numbers can be established. If one selects a count of 1,000 cfu/ml as the separation point: the Histogram shown in Figure 4 indicated at 12.5 hrs all samples with higher counts (in red) detected, while all the samples below 1,000 cfu/ml did not.

Results: Testing of Process Water for the presence of Pseudomonads
Eight different types of process water samples were found to be free of Pseudomonad’s after testing using PSE-B vials and CFC spread plates (data not shown).  Clean process water samples were then inoculated with individual isolates of Pseudomonad’s were used to generate a calibration curves for water, similar to the milk calibration curve. Pseudomonad growth in inoculated process water was measured using PSE-B vials and PA spread plates and was used to generate the Calibration Curve. Detecting vials were confirmed to contain Pseudomonas by the Oxydase test.

Summary
The data presented show equivalency between the BioLumix PSE-B vial and CFC (Pseudomonas agar) plates for the detection of Pseudomonad’s found in commercial milk samples and in inoculated process water samples.  PSE-B vials detected as little as 1-3 organisms (data not shown).
The number of organisms in commercial milk was found to increase over time at refrigerated temperatures and this agreed with a previously published report (Burdova et al 2002) showing the affect of storage temperature on milk shelf-life.
The BioLumix assay is completed in 18 hours and offers an advantage over spread plate methods for time to results and ease of calculation of cfu per gram of milk or water.  A single vial is all that is needed and thus both time and material costs are reduced.  Calibration Curves were easily generated for both milk and water sampling and can be used to generate a cfu/ml of sample in less than 1 day to yield an estimate of cfu/gram.

REFERENCE:  Burdova, O. et al (2002).  Bulletin Vet Med. Poland. 46:325-329. Hygiene of Pasteurized Milk Depending on Psychrotrophic Microorganisms.

International Dairy Show 2013

International Dairy Show 2013
November 3–6, 2013, McCormick Place • Chicago, Illinois

International Dairy Show 2013The International Dairy Show is back in Chicago and is bigger, and better than ever. Dairy, food and beverage processors will see technology and innovations in formulation, processing, packaging, distribution, food safety, and more. Operations, research, and sales and marketing teams will attend to learn trends, cost-cutting innovations, and ways to deliver more value to your customers. We at BioLumix wanted to take this opportunity to invite you to our exhibit (booth #452) and show you what’s new at BioLumix. We continue to innovate, growing our assay repertoire and capabilities.
BioLumix has developed a simple rapid microbiological method for the detection of various groups of bacteria, yeasts and molds. The system can make the microbiology testing simpler, faster and automated, saving you time, labor and money. BioLumix has a comprehensive range of microbiological tests, including specific vials for Coliforms and Pseudomonas. The system is designed to accelerate product release in a simplified automated approach. Complete coliform test results are obtained within 12 hours with one vial substituting for nine or more MPN (Most Probable Number) test tubes. Yeast and mold results are obtained in 48 hours rather than 5-7 days using plate methods. Many products can be introduced directly into the BioLumix test vial without the need of a dilution step. These include yogurts and sour cream, as well as milks.
Dairy product Testing for Yeast and Mold and Coliform
The yogurt can be directly added (Figure 1) into BioLumix vials to measure growth of Coliforms or Yeast and Molds. Specialized high pH BioLumix vials can also be used for yogurt samples. When a low pH yogurt sample is added to the BioLumix high pH Coliform vial (CC), the pH conditions become near neutral. This ensures the yogurt manufacturer to be able to correctly test for coliforms using a direct (without dilution) sample of product. As much as 1 gram of product can be directly tested in each BioLumix test vial.

A clear advantage of the BioLumix vial is that it can be used on the same work-day to yield data about the status of any contamination in dairy samples and thus enable the manufacturer to make a decision on the acceptability of the lot of product for sale and consumption.

Rapid Detection of Pseudomonads in Dairy Products as an Indicator of Product Shelf-Life The data presented in this study suggested that the BioLumix Pseudomonas vials are capable of early detection of Pseudomonads in dairy products and in process water. The system offered a reduction in time to results as compared to the plate methodology and eliminates any product interference. It allows for rapid assessment of any post processing associated problems.

The BioLumix Advantage
• Vial design prevents product interference
• Automation and connectivity allows faster product release
• Real-time communication for immediate action
• Expedited results: most results in 12-18 hours; Yeast and mold assay in 48 hours
• Automated data archiving and audit trail
• Streamlined testing increases laboratory efficiencies
• Paperless laboratory: centralized test data automatically stored and protected
• Barcode capability for automated sample entry
• Environmental testing made easy

Free Product Trial
Give us your most difficult samples and we will test them for free. We will provide you with a detailed report which includes a side-by-side comparison to your current manual methodology. The data generated is strictly confidential and is only used to show the high correlation of results should your company decide to purchase.

We look forward to working with you and earning another satisfied customer!

Rapid Microbiology Testing of Dairy Products using the BioLumix Instrument

Background

Testing Dairy Products using Rapid Microbiology with the BioLumix InstrumentCommercial Dairy Products need to be tested for microbial contaminants.  Dairy products include: cultured dairy products (kefir, cultured buttermilk, sour cream, and yogurt), cheeses (soft cheese products, semi-hard, hard, and extra hard cheeses), processed cheeses, butters, butter creams, dried milks, and ice creams.

Manufacturers require a simple, cost effective and rapid microbiological method to assess samples for the presence of specific organisms as an indication of the sanitary conditions.  The most common dairy microbiology tests include: Aerobic plate count, Yeast and Molds, Coliforms, and could also include some indicator of cold spoilage such as Pseudomonads.  Rapid and early testing for microorganisms can reduce product quarantine time, allows for faster response to contamination, decreases inventory holding and cold warehouse costs, and aids in prediction of product shelf-life for manufacturers.

Troublesome spoilage microorganisms include aerobic Psychrotrophic bacteria, yeasts, molds, heterofermentative lactobacilli, and spore-forming bacteria (Ledenbach and Marshall 2009).  Psychrotrophic bacteria can produce large amounts of extracellular hydrolytic enzymes, and the extent of recontamination of pasteurized fluid milk products with these bacteria is a major determinant of the milk products shelf life. Fungal spoilage of dairy foods is manifested by the presence of a wide variety of metabolic by-products, causing off-odors and flavors, in addition to visible changes in either color or texture and may also cause gassing.

BioLumix has developed a simple rapid microbiological method for the detection of various groups of bacteria, yeasts and molds.  The system can make the microbiology testing simpler, faster and automated, saving manufacturers time, labor and money. BioLumix has a comprehensive range of microbiological tests, including specific vials for Coliforms and Pseudomonas.  The system is designed to accelerate product release in a simplified automated approach.  Complete coliform test results are obtained within 12 hours with one vial substituting for nine or more MPN (Most Probable Number) test tubes.  Yeast and mold results are obtained in 48 hours rather than 5-7 days using plate methods.  Many products can be introduced directly into the BioLumix test vial without the need of a dilution step.  These include yogurts and sour cream, as well as milks.

BioLumix Applications

Yogurt Testing

Yogurt is a dairy product, which is made by blending fermented milk with various ingredients that provide flavor and color.  Manufacturers have responded to the growth in the yogurt market by introducing many different types of yogurt including low fat and no-fat, creamy, bio-yogurt, organic, baby, and frozen.  BioLumix has developed assay methods for measuring contaminating microorganisms in dairy products.

The yogurt can be directly added (Figure 1) into BioLumix vials to measure growth of Coliforms or Yeast and Molds.  Specialized high pH BioLumix vials can also be used for yogurt samples.  When a low pH yogurt sample is added to the BioLumix high pH Coliform vial (CC), the pH conditions become near neutral.  This ensures the yogurt manufacturer to be able to correctly test for coliforms using a direct (without dilution) sample of product.  As much as 1 gram of product can be directly tested in each BioLumix test vial.

Coliform organisms generally include four key groups of enteric bacteria.  They comprise of the following species: Escherichia, Citrobacter, Klebsiella and Enterobacter.  Each of these organisms can grow in the BioLumix high pH CC vial.  Figure 2 illustrates the growth of a coliform (Citrobacter) in the BioLumix CC vial (green) while the Dark Blue curve shows a clean sample.

A clear advantage of the BioLumix vial is that it can be used on the same work-day to yield data about the status of any contamination in dairy samples and thus enable the manufacturer to make a decision on the acceptability of the lot of product for sale and consumption.

Fermented Dairy Products

Yeast and Mold Testing: An example of the growth of a mold in cream cheese is shown below. Figure 3 illustrates the clean test result, using BioLumix Yeast & Mold vials, for the cream cheese product as shown in the Green curve.  The Dark Blue curve illustrates the growth curve in BioLumix YM vials when cream cheese was inoculated with the mold organism Geotrichum candidum.

Coliforms Testing:Similarly, testing of sour cream showed the lack of Coliforms in the product as illustrated in the Dark Blue curve in Figure 4.  The sour cream product sample was found to have other flora as shown by growth in the BioLumix TAC vial which detected total aerobic bacterial counts.  Thus, the BioLumix high pH CC vial was used to show selectivity for the presence or absence of Coliform organisms.

Rapid Detection of Pseudomonas in Dairy Products as an Indicator of Product Shelf-Life
Pseudomonad organisms are a major cause of bacterial spoilage of pasteurized milk and dairy products due to post process contamination.  Early detection of Pseudomonas in can be a predictor of product shelf-life as it is the predominant psychotropic bacteria present.  BioLumix has developed a rapid method for the detection of Pseudomonads in dairy products; the method is also applicable to detection of Pseudomonads in process water.

The BioLumix system was directly compared to the plate count methodology for milk samples stored at refrigerated temperatures and held overnight at room temperatures and to detected Pseudomonads in process water and other dairy products.

Commercial milk products were used to measure the presence of Pseudomonads during refrigerated and elevated temperature storage.  Pseudomonads were present at varying levels in dairy samples and were detected within 16-24 hours using BioLumix vials.  All process water samples tested were free of Pseudomonads by both methods.  Process water samples inoculated with different Pseudomonads strains were found to detect in the BioLumix system.  The vial were selective enough not allowing for growth of unrelated gram positive and gram negative bacteria, mold or yeast.  The combination of the Pseudomonas vial with overnight pre-incubation could serve as an indicator of shelf-life of products.

The data in this study suggests that the BioLumix Pseudomonas vials are capable of early detection of Pseudomonads in dairy products and in processing water. The system offers a reduction in time to results as compared to the plate methodology and eliminates any product interference.  It allows for rapid assessment of problems associated post processing problems.

BioLumix has developed a vial specific for testing of Pseudomonads that are known to commonly contaminate milk and also survive pasteurization, albeit in low numbers. These Pseudomonads may include P aeruginosa, P fluorescens, P putida, and P stutzeri.  Each of these species of pseudomonas was found to grow readily in the BioLumix PSE-B vials.

Summary

The BioLumix System is designed to accelerate product release with a simplified, automated approach.  This yields fast, accurate, real-time results while reducing costs and eliminates the time required for the assays to be completed.  The system offers real-time results of contaminated samples saving hours, possibly days.  The Coliform or Enterobacteriaceae results can be available within 12 hours; Yeast and Mold results within 48 hours.  Thus the BioLumix system allows for rapid detection of Coliforms and Yeast and mold.  For low coliform numbers, one vial can substitute for 9+ MPN tubes.  BioLumix will streamline and simplify the microbiological procedures, save labor and create a paperless laboratory, while generating results that correlate well with plate count methodology.

Reference
Ledenbach L. H. and R.T. Marshall. 2009 In “Compendium of the Microbiological Spoilage of Foods and Beverages” . Chapter Microbiological Spoilage of Dairy Products.

Biolumix Automation Drives Profits

BioLumix Automation Drives Profits!

No longer look at micro testing of raw materials and finished products as a “necessary evil” in remaining cGMP compliant.   Rather, with BioLumix Rapid, Automated Microbiology, you can view microbiology product testing as a position of company strength and competitive advantage!

TIME IS MONEY. . .  we have detailed financial models prepared by our current customers that demonstrate the dramatic impact BioLumix is having when you apply Multiple Days Saved to real profit drivers, such as:  

Biolumix System

  •   Savings as a result of early detection of contamination
  •   Lower cost of inventory
  •   Increase capacity of existing factory and lab
  •   Reduce cost of storage
  •   Lower cost of test related overhead
  •   Savings on cost of capital
  •   Potential improvement in account receivables. . .  all of which directly impact profits!

Automation Drives Profits
The enacted cGMP regulations require manufacturers to ensure that products are free of contamination by objectionable organisms, and that appropriate microbiological testing is conducted.

BioLumix Rapid Microbiology offers a high degree of automation, significant reduction in time to results, reduced staff involvement, and faster product release. . .  all which impact key “operational profit drivers,” such as:

  • Savings as a result of early detection of contamination
  • Lower cost of inventory
  • Increase capacity of existing factory and lab
  • Reduce cost of storage
  • Lower cost of test related overhead
  • Savings on cost of capital
  • Potential improvement in account receivables

 

Contact Us TODAY To Learn More About Our FREE DEMO PROGRAM!

Pseudomonads and Their Rapid Detection

Description of Pseudomonad Organisms

Pseudomonas bacteria (Pseudomonads) encompass gram negative, motile, non-fermenting rods. This genus is ubiquitous in nature and these organisms can impact a number of environments and patient populations. The Pseudomonads may be found in soil, on plant material, in water, and can be isolated from various tissues and body fluids from mammals. In human health, some of these organisms, primarily Pseudomonas aeruginosa, can be an opportunist pathogen and cause serious health problems. If allowed to reach unsafe levels, this organism may cause several health problems including skin rash and other skin infections, ear infection, urinary tract infection, and in rare instances, pneumonia. Other Pseudomonads, for example, P. stutzeri can be isolated from wounds but are generally not associated with human disease. Many Pseudomonads found in the soil can damage plant materials by causing spoilage.

Who tests for Pseudomonas and why?

Water Testing: Pseudomonas aeruginosa is a bacterium commonly found in purified water systems. Pseudomonas grows in water. It thrives at warm temperatures, which is why it is so often associated with spas. It can also grow in purified water systems.

Pharmaceutical and Cosmetic Products: Analysis of FDA product recall data for 134 non-sterile pharmaceutical products from 1998 to September 2006 demonstrated that 48% of recalls were due to contamination by either Burkholderia cepacia, or Pseudomonas spp (Jimenez L. 2007). In cosmetic products, P. aeruginosa was recovered from contaminated mascara material and was identified as the agent responsible for corneal ulcers in the 1970s (Ortho 2009). Pseudomonads can survive and grow in DI water—Contaminated DI water may be the source of microbial contamination if it is used for the final rinse of equipment that has been cleaned and sanitized, and it may be the source of contamination for finished products in these industries.

Dairy and Food: The predominant microorganisms limiting the shelf life of processed fluid milk at 4°C are Pseudomonas spp. these species are able to grow to high numbers during refrigerated storage. Pseudomonas species accounted for79% of the psychotropic isolates that spoiled pasteurized milk (Dogan and Boor 2003). Important characteristics of Pseudomonads include their abilities to grow at low temperatures (3–7?C) and to hydrolyze and use large molecules of proteins and lipids for growth.

Biolumix Offers Two Options for Detecting Pseudomonads

For certain industries it is important to detect Pseudomonas aeruginosa, while for others it is important to detect all Pseudomonas spp, including the closely related Burkholderia cepacia. As a result BioLumix offers two different types of vials: the PSE vial for the detection of P. aeruginosa; and the PSB vial for the detection of all strains of Pseudomonas and for B. cepacia.

Detection of Pseudomonas aeruginosa (PSE Vial)

For the Pharma (OTC), Cosmetic and Nutraceutical Industries the primary cause for concern is the absence or presence of Pseudomonas aeruginosa. P. aeruginosa is common and is able to become an opportunistic pathogen in people and may cause severe disease (Hugh and Gilardi 1974). The ability to detect P. aeruginosa is critical in the non sterile Pharmaceutical products, Cosmetic and Nutraceutical Industries to ensure the product material is safe. BioLumix offers a highly selective media in the form of a test vial (PSE) that primarily only allows for the growth of Pseudomonas aeruginosa organisms. Confirmation of the presence of this organism is accomplished using the simple Oxidase reaction on vial contents. The test sample is merely enriched in TSB (Tryptic Soy Broth) per USP instructions and then tested directly in the BioLumix PSE vial. Other common Pseudomonads and closely related organisms, including B. cepacia and P putida, as examples, are excluded from growth due to the use of antibiotic supplements in the BioLumix PSE vial. P. aeruginosa is typically more antibiotic resistant than other Pseudomonas organisms (Blazevic, DL et al 1973). Figure 1 illustrates the growth curve of Pseudomonas aeruginosa ATCC 9027 in the BioLumix PSE vial.

KEY:Dark Blue Curve- P. aeruginosa Green Curve- Negative Control

Detection of other Pseudomonads (PSB Vial)

For many industries including the dairy industry and manufacturers using water, there is a need to test for all Pseudomonads as they impact these industries economically. Other Pseudomonads may include P. fluorescens, P. putida, and P. stutzeri. Burkholderia cepacia, can also be detected using the BioLumix PSE-B vial. Specific to the use of water in manufacturing: Pseudomonas bacteria can be found naturally in the ground and within drinking water sources such as aquifers. Contamination of either dairy products or water systems by Pseudomonads is something to avoid and early detection of goods using a rapid microbiological detection system such as the BioLumix Instrument System, would offer an advantage to the manufacturer. Figure 2 illustrates the growth of many types of Pseudomonads and Burkholderia cepacia in the BioLumix PSE-B vial.

KEY: Dark Blue Curve- B. cepacia; Green Curve -P aeruginosa; Light Blue Curve – P. putida; and Red Curve– P. fluorescens growth

REFERENCES

Blazevic, DJ, Koecke, M.H., and Mastsen J.M. (1973). Incidence and identification of Pseudomonas fluorescens and Pseudomonas putida in the clinical laboratory. Applied Microbiology 25: (1)

Dogan, B. and Boor, K J. (2003). Genetic diversity and spoilage potentials among Pseudomonas ssp. isolated from fluid milk products and dairy processing plants. Appl. Microbiol.,69: 130-138.

Hugh, R. and Gilardi, G. (1974) In “Manual of Clinical Microbiology” Edited by Spaulding, Lennette, Spaulding and Truant. Chapter 23 Pseudomonas.

Jimenez L.(2007). Microbial diversity in pharmaceutical product recalls and environments. Review. PDA J Pharm Sci Technol. 2007 Sep-Oct;61(5):383-99.

Ortho D. (2009). Insight into Cosmetic Microbiology, Chapter 8 263-267

Come and See Us at the International Dairy Show 2011 in Atlanta, GA September 19th – 21st

For the first time BioLumix will be exhibiting at this year’s International Dairy Show in Atlanta, GA.  In the last three of years, BioLumix has established itself as a leader of innovation in Rapid Microbiological Methods.  With our breakthrough technology we have found tremendous success in rapid microbiological testing, selling over 200 instruments.  We would like to invite you to our booth (#1816) to demonstrate our instrument, ready-to-use vials and discuss how the system may benefit you.

Traditional methods are slow, tedious, labor intensive, and often not suitable for assessing the quality and shelf-life of perishable dairy products.  BioLumix can make the microbiological testing simpler, faster, and automated – saving your company time, labor and money. We offer a comprehensive range of microbiological tests for raw ingredients and finished products, as well as processing water and environmental testing.

The BioLumix system is designed to accelerate product release with a simplified, automated approach. This yields fast, accurate, real-time results while reducing costs. No more waiting for days for completed assays.  We offer real-time results of contaminated samples saving hours, possibly days. Completed Coliform or Enterobacteriaceae results are available within 8-12 hours; Yeast and Mold results within 48 hours. BioLumix will streamline and simplify the microbiological procedures, save labor and create a paperless laboratory, while generating results that correlate well with plate count methodology.

Dealing with difficult to read plates or manual data transfer is a thing of the past.  With automated monitoring of ready-to-use assay vials and automated data processing and archiving, the microbiologist’s job got a lot easier with the same accurate results in less than half the time.  See our innovative vial design which prevents product interference even when directly testing products such as yogurt and other cultured dairy.  Come to our booth (#1816) or contact us directly (734-984-3100) to learn more about our 12 hour Coliform assay, our 48 Yeast and Mold assay, and direct sample introduction = no dilutions.  

The BioLumix Advantage

• Vial design prevents product interference

• Automation and connectivity allows faster product release

• Real-time communication for immediate action

• Expedited results: coliform and Enterobacteriaceae results within 12 hours; Yeast and mold assay in 48 hours

• Early warning of contaminated samples

• No decimal dilutions required – direct sample introduction to vials

• Reduced risk of microbial contamination

• Automated data archiving and audit trail

• Streamlined testing increases laboratory efficiencies

• Paperless laboratory: centralized test data automatically stored and protected

• Barcode capability for automated sample entry

• Environmental testing made easy

Hear What Our Customers Are Saying

Don’t just take our word for it, talk to our customers.  We have recently conducted a customer survey and are proud to share that we have 100% customer satisfaction and that all of our customers would recommend the BioLumix.  Unanimously, our customers agree – the main features of the BioLumix system are:  Speed to results, simplicity of use, accuracy and clarity of data presentation. Please contact our customers to discuss their first hand experience.

Free Product Trial

Give us your most difficult samples and we will test them for free.  We will provide you with a detailed report which includes a side-by-side comparison to your current manual methodology.  The data generated is strictly confidential and is only used to show the high correlation of results should your company decide to purchase.

We look forward to working with you and earning another satisfied customer!

Rapid Coliform, Yeast and Mold Testing of Yogurt

Testing of Yogurt and Other Dairy Products

Yogurt is a dairy product, which is made by blending fermented milk with various ingredients that provide flavor and color.  Manufacturers have responded to the growth in the yogurt market by introducing many different types of yogurt including low fat and no-fat, creamy, bio-yogurt, organic, baby, and frozen.  The popularity of yogurt has increased due to its perceived health benefit resulting in significant increase in consumption (Chandan et. al 2006) as shown in Figure.

Recently Reuters reported that Dannon, the world’s largest yogurt maker, announced that it expects annual double digit percentage dairy sales growth in the United States over the long term.

Microbiological Testing of Yogurt

Undesirable microorganisms constitute the primary hazard to safety, quality, and wholesomeness of milk and dairy foods.   The primary assays performed in yogurt are yeast and mold (requiring up to 7 days for results) and the coliform assay that is used as an indication of appropriate processing. Traditional methods are slow, tedious, labor intensive, and often not suitable for assessing the quality and shelf-life of perishable dairy products. 

 The emphasis on the programs based on HACCP (Hazard Analysis and Critical Control Points) for total quality management in the dairy industry and increased demand for microbiological surveillance of products, process, and environment have led to increased interest in rapid methods and automation in microbiology.

BioLumix technology can make the microbiological testing simpler, faster, and automated.  Saving time, labor and money. 

The BioLumix test method for detection of coliform and yeast & molds involves a direct addition of the sample into ready to use vials and automated monitoring of the samples in the instrument.  The coliform assay is completed in 12 hours, while most contaminated samples are flagged within a typical shift.  The yeast & molds assay is completed in 48 hours as compared to the 5 days required for the standard assay.

The ready–to-use vials come with media that is pre-adjusted for pH, such that after the addition of the sample the appropriate pH for the growth of the microorganisms is attained.  BioLumix has developed such a media that is custom made with a higher pH to accommodate the low pH of yogurt while still maintaining the capability to test as much as 1.0 gram of product directly in the vials.    

Coliform Assay:

The curves obtained by the addition of 1.0 gram of yogurt to a high pH vial (pH 8.2) of coliform are shown:

The Dark Blue curve shows the 1.0 gram sample.  All product interference has been eliminated as depicted by the flat part of the curve.  The Green Curve illustrates a yogurt sample inoculated with a coliform.




In North America, BioLumix has tested yogurt samples manufactured by a number of companies.  The Table below includes a series of products from one such company Yoplait, Ontario, Canada.  These samples include low fat and regular varieties. 

Lemon Cream Pie Light Fat Free
Key Lime Pie Original 99% Fat Free
Strawberry Shortcake Light Fat Free
Raspberry Mousse Whips
Strawberry Thick & Creamy Low Fat
Key Lime Pie Original
Delights Parfait Chocolate Raspberry

All un-inoculated products resulted in flat curves as seen in the Figure.  Product interference was not found.

All products tested were shown to be clean (<1 coliform/ gram).  All inoculated products detected in the system in less than 8 hours.

Yeast and Mold Assay:
Similar results were obtained for yeast and molds. The curves show the results obtained with a variety of yogurt products.

Fieldberry Stirred Yogurt Dark blue
Raspberry Stirred Yogurt Green
Raspberry Stirred Yogurt-inoc CAD L- blue
Yoplait Mingo Red
Yoplait Mingo-inoc ASP Purple
Tubes- Raspberry Yellow
Tubes- Grapes Tan
Irresistible Creamy yogurt Vanilla Dark green

The inoculated samples (light blue- inoculated with Candida albicans; purple inoculated with Aspergillus niger) detected in less than 24 hours.  All the un-inoculated samples were clean and did not detect in the vials.  A total of 50 different yogurts were tested using this method and the data showed that all the samples that contained either yeast or mold detected in the system and none of the clean samples detected.  The plate count results agreed 100% with the BioLumix vial results.

Conclusion:

The BioLumix system is designed to accelerate product release with a simplified, automated approach. This yields fast, accurate, real-time results while reducing costs. The BioLumix offers real-time results of contaminated samples saving hours, possibly days. Completed Coliform or Enterobacteriaceae results are obtained within 12 hours; Yeast and Mold results are obtained within 48 hours.

References:

R.C. Chandan, C.H. White, A. Kilara, and Y.H. Hui. 2006. in Manufacturing Yogurt and Fermented Milks. Blackwell Publishing.

New Bacillus Cereus Vial for BioLumix

Bacillus cereus…

Bacillus cereus is a Gram-positive, facultatively aerobic spore former whose cells are large rods and with spores that do not swell the sporangium.  B. cereus spores are more resistant to heat and chemical treatments than vegetative pathogens such as Salmonella, and E. coli.

Bacillus cereus is responsible for 5% of foodborne illnesses worldwide, causing severe nausea, vomiting and diarrhea. Detecting potential B. cereus as quickly and easily as possible is of paramount importance. B. cereus food poisoning has two recognized types of illness are caused by two distinct metabolites. The diarrheal type of illness is caused by a large molecular weight protein, while the vomiting (emetic) type of illness is believed to be caused by a low molecular weight, heat-stable peptide.

The symptoms of B. cereus diarrheal type food poisoning include watery diarrhea, abdominal cramps, and pain occurs 6-15 hours after consumption of contaminated food. Nausea may accompany diarrhea, but vomiting rarely occurs. Symptoms persist for 24 hours in most instances. The emetic type of food poisoning is characterized by nausea and vomiting within 0.5 to 6 h after consumption of contaminated foods. Occasionally, abdominal cramps and/or diarrhea may also occur. Duration of symptoms is generally less than 24 h.

A wide variety of foods including meats, milk, vegetables, and fish have been associated with the diarrheal type food poisoning. The vomiting-type outbreaks have generally been associated with rice products; however, other starchy foods such as potato, pasta and cheese products have also been implicated. Food mixtures such as sauces, puddings, soups, casseroles, pastries, and salads have frequently been incriminated in food poisoning outbreaks.

Two different methods are described in BAM1 for the detection of B. cereus: (i) plate count method with Mannitol–Egg Yolk–Polymyxin (MYP) agar and (ii) a Most Probable-Number (MPN) method with Tryptic Soy Broth (TSB) supplemented with 0.1% Polymyxin Sulfate.  The MPN method allowed for better recovery and therefore for higher counts than MYP2, probably due to the better ability of the broth to recover injured organisms.

BioLumix Vial:

A new vial (BCP) was developed specifically for B. cereus detection in the BioLumix system.  It uses the CO2 sensor at the bottom of the vial.  The medium contains growth promoting ingredients peptones, casein digest and Yeast Extract. Sodium Pyruvate is added to facilitate the resuscitation of damaged Bacillus cells. Manganese Chloride is added to aid the germination of spores.  Inhibitors include Cyclohexamide to prevent growth of YM; LiCl, Cyclohexamide and Polymixin B are used as inhibitors.

                                    ATCC 10876- Dark Blue; ATCC 11778- Green; ATCC 14549- Light blue; and ATCC13061-Red

 Twenty five cultures of gram negative organisms and Twenty one cultures of gram positive organisms were tested in the BC vial.  None of the gram negative organisms grew in the vial and all gram positive organisms did not grow except one strain of Enterococcus feacalis (ATCC 19433). The new BC vial recovers well vegetative cells as well as spores. The method used is very simple, just pipette the diluted sample into the vial.  The results are obtained in 24 hours or less.  This vial is ready for free product trials.

References:

  1. E. Jeffery Rhodehamel and Stanley M. Harmon (2001). Bacteriological Analytical Manual, Chapter 14: Bacillus cereus (2001). US Food and Drug Administration.
  2. N. M. Harper, K.. K. Getty, K. A. Schmidt, A. L. Nutsch, and R. H. Linton. Comparing the Mannitol–Egg Yolk–Polymyxin Agar Plating Method with the Three-Tube Most-Probable-Number Method for Enumeration of Bacillus cereus Spores in Raw and High-Temperature, Short-Time Pasteurized Milk. J. Food Prot.71:473–478.

Rapid Detection of Coliforms in Yogurt

What are coliforms?


Coliforms are a group of bacteria commonly found in the environment, including soil, surface water, vegetation and the intestinal tracts of warm-blooded animals. Most coliforms do not cause disease, but a small percentage can cause illness in people, especially young children, the elderly, and those with weakened immune systems. Coliforms are rod-shaped Gram-negative non-spore forming organisms. They can ferment lactose with the production of acid and gas when incubated at 35-37°C. Coliform bacteria are not a traditional taxonomic group, like Salmonella, Escherichia coli, or Listeria. Instead, the coliform bacteria are a collection of strains in the Enterobacteriaceae family. E. coli, Enterobacter spp., Klebsiella spp., and Citrobacter spp. are the most common coliforms.

How do coliforms get into milk?

Coliform bacteria are normally shed in the feces of healthy livestock, including dairy cattle. Thus, poor herd hygiene, contaminated water, unsanitary milking practices, and improperly washed and maintained equipment can all lead to elevated coliform counts in raw milk at the dairy farm. The milking of cows with wet and manure-soiled udders and inadequately cleaned milking equipment are the most common ways for coliform bacteria to enter milk on-farm.

Coliforms in milk: What does it mean?

The coliform bacteria count is used as an index of the level if sanitation and/or water quality employed in the handling and processing of milk products. In dairy products, the process of pasteurization easily kills coliform bacteria. Therefore, the finding of coliforms in pasteurized products indicates some level of contamination has occurred after pasteurization during product manufacturing or packaging. Hence, coliforms are used as a general indicator of sanitary conditions in dairy production and processing environments.

Traditional methods for testing Coliforms


Traditionally the agar plate count method using VRBA (Violet Red Bile Agar) and the MPN methods are being used.  The plate count method takes 24 hours to perform and can use 1.0 ml of 1:10 dilution and as a result has a sensitivity of <10 cfu/gram.

When higher sensitivity is required the MPN (Most Probable Number) method can be used.  Multiple tubes (typically 3) are inoculated for each dilution.  The method involves the inoculation of at least 3 decimal dilutions (a total of 9 tubes) of LST (Lauryl Tyrptose Broth).  Any LST tube that shows growth and gas production is transferred to BGLB (Brilliant green lactose bile), the MPN is calculated based upon the positive BGLB tubes.  This assay is very labor intensive and takes 3-5 days to complete.

Rapid High volume Automated Method for the Detection of Coliforms

Direct inoculation of Product and Speed to Results


In a recent study 25 different types of yogurts were tested by the BioLumix method and the plate count method.  The BioLumix ready to use vials were directly inoculated with 1.0 ml of various yogurts and monitored in the BioLumix system for 12 hours.  Figure 1 shows the curves obtained.  Key:  Dark blue – Grape yogurt, Green – Grape yogurt inoculated with Citrobacter, Lt Blue – Raspberry yogurt, and Red – Raspberry yogurt inoculated with E. coli.

 All products tested using the automated BioLumix assay for coliforms yielded results in a considerably shorter test time (typically 10-12 h) than the conventional Violet Red Bile Agar (VRBA) method (24 h to 72 h with confirmation). The BioLumix method can detect <1 cfu/gram of product, being 10 times more sensitive that the plate count method.  The BioLumix coliform medium had better selectivity in detecting coliforms, eliminating the need for the confirmation step.

Labor Savings

The BioLumix System offers a significant reduction in time to obtain results while reducing hands-on labor due to its automation and simplicity of use.  The procedure involves 2 simple steps:

  1. Add 1.0 ml of product directly to the ready to use vial
  2. Add the sample information to the computer

The system automatically will run the system and generate the desired reports. Therefore, there is no sample preparation required no media preparation or counting of plates.  Due to its simplicity the assays can be performed by less skilled personnel.

Automation

The BioLumix system is a fully automated system offering automated data achieving, and automated reporting.  It offers the ability to operate the laboratory as a paperless operation. Due to its connectivity through the Intranet it allows for automated transfer of product release information to the warehouse.

Free Product Trial

Interested in a free product trial?  Contact BioLumix today!  P.734-984-3100.

Fast, Accurate Dairy Microbiology Testing For Yeast and Mold

Cultured dairy products are the fastest growing area of consumer dairy consumption.1 Rapid dairy microbiology testing for yeast and mold, the most common contaminants in these products, is critical to the industry and consumer safety. Yeast and mold can cause substantial economic losses and produce harmful metabolites.2

Traditional dairy microbiology testing requires 5 days to complete using the plate count methodology. Sending samples to outside labs adds to the cost and time of testing. A microbiological system developed by BioLumix has cut dairy microbiology testing time to as little as 24-48 hours. With the BioLumix microbiological system, manufacturers can streamline existing dairy microbiology testing operations or internalize their outsourced testing for reduced costs and improved efficiency.

In-house microbiology testing with the BioLumix system is simple. Samples are placed in ready-to-use, disposable vials that contain a transparent solid sensor at the bottom. These sensors detect the production of CO2 by all yeasts and molds. This means that if yeasts and molds begin to grow in the medium above the sensor, they will produce CO2 that will diffuse into the sensor and change the sensor’s color. Only gases can penetrate the sensor, which means the optical readings cannot be masked by any liquids, microorganisms, and/or particulate matter.

The BioLumix microbiological system can then detect any optical changes, presenting the results of the assays as soon as detections occur with no need for involvement of an operator or a microbiologist, providing significant savings on laboratory labor. Any out-of-spec samples are flagged in red, demanding attention. The greater the contamination level, the faster the result, ensuring a rapid warning of poor-quality raw materials, finished products or any equipment line issues. The speed of these dairy microbiology results ensure that dairy product manufacturers don’t have delays from testing so they can move products from the warehouse to the marketplace quickly and without premature spoilage.

A recent dairy microbiology study assessed the BioLumix microbiological system with various cultured dairy products that were clean, naturally contaminated, or inoculated with different yeast or mold strains. This included products with high levels of active starter culture or probiotics.3 The BioLumix microbiological system demonstrated 100% accuracy in detecting over 100 different combinations of clean contaminant products, which was comparable to plate count methodology, the current standard in dairy microbiology. However, the BioLumix microbiological system reduced detection time from 5 days to 24 hours for most yeast and 48 hours for mold.

The BioLumix microbiological system simplifies and automates your laboratory procedures by delivering shorter sample preparation, automated real-time communication, fast product release, and early warning of contamination, as well as automated data entry, data archiving, report generation and product release. With reliable dairy microbiology results in just 24-48 hours, dairy manufacturers can focus on efficiency and product quality. For a full reprint of the study or any further information on the BioLumix microbiological system, visit www.mybiolumix.com or call 1-734-984-3100.

References

1. Cogan TM, et al. Advances in starter cultures and cultured foods. J Dairy Sci. 2007;90:4005-4021.

2. Hussein HS, Brasel JM. Toxicity, metabolism and impact of mycotoxins on human and animals. Toxicology. 2001;167:101-134.

3. Eden RF, Brideau R. Rapid automated detection of yeast and molds in cultured dairy products. International Association of Food Protection Annual Meeting 2009.

Karen F. Vieira, Ph.D.