Rapid test for Listeria

Certified and trusted Validated against
ISO 11290-1:2017
Holds an
AOAC® PTMSM Certification Download certificate

NEMIS Technologies Listeria Test

Listeria is a leading cause of foodborne illness and costly product recalls. Protect your customers and your business with the N-Light™ Listeria Test from NEMIS Technologies. Our simple and effective testing platform allows you to find pathogens sooner and stop outbreaks before they start. Best of all, our tests can be properly used with minimal training. They’re the simple and cost-effective solution to your L. monocytogenes testing problem.

The NEMIS N-Light™ Listeria monocytogenes Rapid Test is built on our proprietary Aquaspark™ platform which leverages pioneering phage technology to quickly detect even small amounts of live bacteria. Unlike traditional lab tests that take days to get results, the NEMIS N-Light™ Listeria monocytogenes Test produces actionable results in as little as 24 hours. Fast, accurate, easy to use. NEMIS Technologies is revolutionising food safety.

Listeria monocytogenes — status quo

Listeria infections, often linked to contaminated food products, are primarily caused by the bacterium Listeria monocytogenes. Listeria monocytogenes is a Gram-positive bacterium that is among the leading causes of death from foodborne illness. Although Listeriosis is not the leading cause of foodborne diseases, severe infection has a case-fatality rate of 15% to 30%.

AYOPI Groups are at the Highest Risk

CDC estimates that Listeriosis is the third leading cause of death from foodborne illness, with about 260 deaths per year.

Pregnant women and newborns

Adults aged 65 and older

People with weakened immune systems

Did you know that you invite Listeria into your factory every day?

The natural home of Listeria monocytogenes is in the fields and, thus, in soil, water, and even harvested vegetables. In that condition, it is termed a saprophyte, as the organism does not cause any harm in this condition. It becomes an issue only when the crops are harvested and brought into the factory. Considering this, most food manufacturers invite Listeria monocytogenes into their factories every day. Every piece of raw material could have Listeria monocytogenes on it.

Nevertheless, raw and fresh produce is consumed daily without people getting sick. This pathogen primarily affects people with a weak immune system and must grow in the food before an infectious dose is reached. The problem is that Listeria monocytogenes can multiply from deficient numbers and reach dangerous levels even at fridge temperatures, so preventing even deficient numbers from contaminating food is crucial.

Swiss precision meets Listeria detection excellence in our best-in-class rapid test kits

N-Light™ Listeria monocytogenes
For Actionable Results In 24 H

N-Light™ Listeria monocytogenes is a qualitative test method for rapidly detecting the foodborne bacterial pathogen Listeria monocytogenes. It is suitable for in food processing areas and equipment as part of an environmental monitoring program. Final test results are available 24 hours after sampling.

N-Light™ Listeria monocytogenes 
tube contains a unique, innovative technology

The Biosafety Cap for safe
on-site enrichment
Pioneering phage
technology
Patented AquaSpark™
platform for detection of live bacteria
See our technology
in action

Consider your sampling needs:
N-Light™ MaxiSampler vs N-Light™ swab

Patent pending
By choosing the right tool for each surface type and size, you can meet regulatory guidelines effectively while maximizing sampling efficiency and accuracy.

N-Light™ MaxiSampler

Patent pending
  • Designed for Large Surface Coverage Excels in sampling larger, flat surfaces such as floors, walls, and countertops. Provides broader detection of potential contamination across sizable zones.
  • Guideline Endorsed for Broader Surveillance Environmental monitoring guidelines often endorse sponges for larger, straightforward areas to capture a comprehensive view of contamination risks.
  • Surface Area With a typical range up to 0.3 m² (like a 30×30 cm area), N-Light™ MaxiSampler maximizes sampling on expansive surfaces, offering robust environmental surveillance.

N-Light™ swab

  • Ideal for Hard-to-Reach Areas Swabs are perfect for narrow or intricate surfaces such as equipment joints, cracks, and small parts that might otherwise be missed.
  • Recommended by Guidelines for Small Surface Sampling Many guidelines, such as those from the FDA and ISO, suggest swabs for sampling limited areas or surfaces with complex geometries.
  • Surface Area Typically covers around 0.1m² (like a 10×10 cm area), making swabs ideal for focused or spot sampling on high-touch or high-risk zones.
Learn more

Simple, Effective, Testing process

1. Sample
2. Transfer
3. Incubate
24 h / 37 °C
4. Activate
5 min
5. Measure
10 s

Recommended products:

N-Light™ Listeria spp. Learn more
N-Light™ Salmonella Risk Learn more
N-Light™ E.coli Learn more
N-Light™ ATP Learn more
N-Light™ MaxiSampler: Revolutionising Surface Sampling Learn more
N-Light™ L.monocytogenes
NEMIS product REF 00009

Product description

N-Light™ Listeria monocytogenes is a qualitative test method for rapid detection of the foodborne bacterial pathogen Listeria monocytogenes. The test method is suitable for use in food processing areas and equipment as part of an environmental monitoring program. Final test results are available 24 h after sampling.

Storage conditions: 2-8 °C / 36-46 °F, DO NOT FREEZE
Transport conditions: ambient (short duration only)
HS tariff number: 38221900
Country of origin: CH

Each test consists of the following components:

  • N-Light™ Biosafety Tube, filled with N-Light™ L. monocytogenes Enrichment Broth, 2 ml
  • N-Light™ Dispensing Closure, containing the N-Light™ L. monocytogenes AquaSpark® tablet, 1 pc. / 13 mg

Technical specifications

NEMIS tests each production batch against the specifications listed below.

General characteristics Specification
Broth general appearance Yellowish, clear waterlike solution
Broth visible turbidity No particles
Broth optical density (A600nm) < 0.10
Broth Volume 1.80 – 2.20 ml
Broth pH value 6.70 – 7.20
Functionality test (Background) < 10 000 RLU (NEMIS Luminometer)
Quantity of AquaSpark® Internal specification
Microbial performance Specification
Sterility control No growth, 7 days @ 37 °C
L. monocytogenes ATCC 13932 Positive result
L. monocytogenes ATCC 19111 Positive result
L. ivanovii WSLC 3009 Negative result
E. faecalis ATCC 29212 Negative result
E. faecalis ATCC 29212 Negative result

Certificates of analysis are available on request.

Packaging specifications

General characteristics Primary packaging
(test tube) Secondary packaging
(product box)		 Tertiary packaging
(distributor box)
Amount 1 test 50 tests (1 x 50) 300 tests (6 x 50)
Bar code / GTIN See below 7649994979201 7649994979218
Length 1.9 cm 26.2 cm 36.3 cm
Width 1.9 cm 11.5 cm 27.4 cm
Height 11.1 cm 11.6 cm 24.4 cm
Net weight 0.010 kg 0.600 kg 3.950 kg
Total plastic amount 0.008 kg 0.376 kg 2.256 kg
Non-reusable plastic amount
— in the product
— in the packaging		 0.008 kg
0.000 kg		 0.375 kg
0.001 kg		 2.250 kg
0.006 Kg

Lot and serial number of the test

Each test has a unique number printed on the tube label. The human readable format is LLLLLLL-XXXXX. Additionally, this number is encoded without the hyphen in a linear barcode of type Code 128:

  • LLLLLLL: 7-digit lot number
  • XXXXX: 5-digit consecutive number

N-Light™ L.monocytogenes Required materials

  1. N-Light™ Listeria monocytogenes test tubes
  2. NEMIS Bench-top Luminometer
  3. NEMIS Dry Block Heater
  4. Kitchen Timer
  5. Optional: N-Light™ Activation Tool (REF 00008)
  6. N-Light™ sampling devices containing compatible moistening solution
    • N-Light™ sterile dry swabs BP with separate PBS buffer (REF 00039)
    • N-Light™ sterile dry swabs BP with separate neutralizer (REF 00037)
    • N-Light™ sterile MaxiSamplers with separate PBS buffer (REF 00060)
    • N-Light™ sterile MaxiSamplers with separate neutralizer (REF 00064)
N-Light™ Listeria monocytogenes AOAC certificate N-Light™ Listeria monocytogenes Brochure N-Light™ Listeria monocytogenes Instruction for Use

Training

At NEMIS, your success is our priority. Our experts are here to guide you with comprehensive training resources, including instructional videos, to help your team confidently and accurately perform procedures. For on-demand training requests, please contact us at techsupport@nemistech.com.

FAQ

The N-Light™ L.monocytogenes test is a qualitative test for rapidly detecting the foodborne bacterial pathogen Listeria monocytogenes. It is intended for use in food processing areas and equipment as part of an environmental monitoring program. Being intuitive, rapid, cost-effective, and lab-free, it offers an affordable solution to scale testing and empowers your quality management process.
AquaSpark™ are dioxetane derivatives bearing substrates that specifically react with targeted enzymes. Being fully synthetic molecules, the platform offers a wide array of variations that allow rapid detection of enzymatic activities, amongst other applications.
RLU stands for Relative Light Units and is the unit of measure used in the NEMIS luminometer. RLU values are proportional to the amount of AquaSpark™ light emission induced by the specific enzyme. For each NEMIS test, a certain threshold for presumptive positive and presumptive negative results has been defined. In the case of the N-Light™ L.monocytogenes test, a sample is considered presumptive positive when the signal is above 20'000 RLU.
The test combines two core technologies: NEMIS bacteriophages (selective enrichment) and AquaSpark™, an ultrasensitive chemiluminescent molecule that reacts with an enzyme (PI-PLC) produced specifically by Listeria monocytogenes. In practice, the user follows a simple protocol:
  • Collect the sample using a swab.
  • Transfer it to the enrichment tube.
  • Incubate it for 24 hours.
  • Release the AquaSpark™ tablet into the tube.
  • Incubate the activated tube at 37 ˚C for 5 minutes
  • Measure results
If Listeria monocytogenes is present in your sample, they will initiate a reaction that generates light which the Luminometer measures, thus yielding a presumptive positive result. Figure 1 shows what happens when the AquaSpark™ tablet is released into a sample containing L.monocytogenes.
Results can be obtained after 24 hours of incubation at 37 °C. A shorter incubation time than 23 hours is not AOAC-validated and not encouraged if minimal contamination should be uncovered. On the other hand, tubes can be incubated for up to 72 h yielding the same results.
The N-Light™ L.monocytogenes test broth contains a mixture of nutrients (for bacterial growth) combined with selective factors (limiting the growth of non-target bacteria) such as antibiotics and NEMIS proprietary combination of bacteriophages. This combination creates an ideal culture medium for Listeria monocytogenes leading to superior sensitivity and specificity of the test. Its unique formulation inhibits the growth of competing bacteria and makes the test more reliable in challenging environments. Additional data about the N-Light™ enrichment broth can be found here.
The only required equipment is the NEMIS dry block heater and the NEMIS Luminometer. They can be used on-site without any laboratory infrastructure. It is recommended to perform the test in a separate room, distant from the production environment.
Yes, the N-Light™ L.monocytogenes has been certified in the AOAC® Performance Tested Methods SM Program and validated against the reference method ISO 11290-1:2017.
Cause FP FN
Inappropriate storage conditions (see question 53)
Shorter incubation time
Incubate at a lower temperature than 37 °C
Incubate at a higher temperature than 37 °C
Measurement of the chemiluminescent signal without having incubated the sample according to the N-Light™ L.monocytogenes test Instructions For Use (IFU)
Measu Immediate or delayed measurement of the sample after tablet release contrary to the specifications in the N-Light™ L.monocytogenes test Instructions For Use (IFU)
Any deviation from the N-Light™ L.monocytogenes test IFU can lead to FP or FN results. The growth of certain Bacilli, S.aureus, and L.ivanovii could theoretically cause positive signals as they produce the same enzyme PI-PLC which cleaves the AquaSpark™ molecule and leads to the expression of chemiluminescent light. However, the proprietary NEMIS enrichment broth contains both antibiotics and bacteriophages that specifically eliminate these microorganisms.
The test is specific for Listeria monocytogenes, which is the only pathogenic species for humans. Negative results will be obtained for other Listeria species if they are present in the sample.
The test is sensitive to detect L.monocytogenes starting from single-digit bacteria in the sample. Good swabbing practice and accurate compliance with the test IFU are required.
No, it does not. The detection mechanism relies on the hydrolysis of AquaSpark™ by an enzyme (PI- PLC) that is only expressed by viable Listeria monocytogenes. Therefore, negative results will be obtained for dead bacteria.
Yes, VBNC bacteria may be detected. Unlike conventional plating methods, the test detects Listeria monocytogenes as long as they are metabolically active. Preliminary research has demonstrated that VBNC cells cleave the AquaSpark™ and can be distinguished from dead cells in an assay format in the laboratory. Further research is ongoing.
It is possible to collect samples from production lines or sites that have not been recently cleaned. Sample location and application of N-Light™ L.monocytogenes should be categorized as follows:
  • Clean Surfaces
    The AOAC has validated the full performance of N-Light™ L.monocytogenes.
  • Food or dirt residue exposed surfaces within the production or before cleaning
    Samples taken from production lines (both during and after production) and other places in the facility that are regularly cleaned are well within the capacity of our test. Make sure not to overload the sample with food residues. Rather go into niches and cavities of machines and apply pressure on surfaces. Sampling more “dirt” is not necessarily useful as persistent Listeria on equipment or infrastructure should be detected.
  • Direct sampling of food or in places of high dirt / food residue concentration
    Meticulous sampling is required to ensure no test tube overload. Do not directly collect food residues. Examples of high load sampling spots are uncleaned drains, smeared water tanks, or the inside of uncleaned food residue collection containers.
We recommend that sample locations with overload potential should be either avoided or alternative sampling spots in close vicinity be taken. In case of doubt, do not hesitate to reach out to techsupport@nemistech.com
Hot spots that accurately indicate potential product contamination should be preferentially sampled. Please refer to your Hazard Analysis and Critical Control Points (HACCP) plan.
Optimally, high-risk spots should be swabbed on a daily basis after each cleaning or production shift. In case of a positive result, immediate corrective action should be taken with re-cleaning and re-testing until a passing result can be measured. Lower-risk control points may be tested less frequently.

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