Food safety kits

Lateral flow immunoenzymatic tests

Lateral flow tests are based on the interaction between a specific antibody for the target molecule and the molecule itself, detecting the reaction with an enzyme that produces a visible signal. The formation of colored bands indicates a positive or negative result.

This is a rapid, visually-read test.

The test procedure is simple and generally involves three stages:

• Protein extraction, obtained by mixing the sample with the extraction solution
• Dilution, resulting in the sample to be tested on the rapid test
• Reading the result, which appears as the formation of specific bands on the test strip

These tests provide rapid results for the qualitative detection of contaminants, allergens, proteins, and are widely used in screening tests or on-site testing.

Chromogenic tests

Colorimetric tests for the selective detection and counting of microorganisms measure the catalytic activity of the primary metabolic oxidoreductase enzymes, allowing a precise correlation between the measured enzymatic activity and the microbial load in the sample. The analytical procedure relies on colorimetric detection, using redox indicators to observe changes in the redox state of the reaction medium, caused by the action of enzymes involved in respiration and fermentation processes.

Tests for protein residues are independent of ATP. Protein residues extracted with the buffer react with the color indicator present on the buffer. This interaction causes a pH decrease, leading to a rapid colorimetric reaction. The intensity of the color change can indicate the level of contamination.

These are rapid, visually-read tests.

Bioluminescence tests

The bioluminescence test with a bioluminometer is a rapid and effective method for checking the hygiene of surfaces, detecting the presence of ATP (adenosine triphosphate), a molecule found in all living cells, including bacteria and other microorganisms. The test uses specific swabs, which, once in contact with the surface, are inserted into the bioluminometer. The instrument measures the light emitted during the bioluminescence reaction between ATP and the luciferin/luciferase reagent, providing a value that indicates the level of contamination.

The test can be performed on-site, is very fast, and requires minimal equipment and training.

qPCR tests

PCR (Polymerase Chain Reaction) is a method used to amplify a specific DNA sequence in a reaction containing, among other components, a thermostable DNA polymerase, nucleotides, and primers complementary to the target sequence.

The method involves the following steps:

• Denaturation, alignment, and extension: The DNA molecule denatures when the solution is heated, separating into two strands. As the solution cools, the primers bind to the target sequences in the separated DNA strands, and the DNA polymerase synthesizes a new strand by extending the primers with nucleotides, creating a copy of the DNA sequence (amplicons).

• Amplification: Repeated cycles of denaturation, recombination, and extension exponentially increase the number of target amplicons.

• Measurement: In real-time PCR, the signal is measured at each cycle using fluorescent probes. The fluorescence is measured by a detector, and the associated software tracks the fluorescence intensity in relation to the number of cycles, allowing the presence or absence of the target organism to be determined.

ELISA immunoenzymatic tests

ELISA tests are based on the interaction between a specific antibody for the target molecule and the molecule itself, detecting the reaction with an enzyme that produces a detectable signal using an optical reader.

This test is widely used for the quantitative and qualitative determination of contaminants, allergens, and proteins.

The method involves the following steps:

• Extraction of the target molecule
• Reaction, binding between the specific antibody and the target molecule, if present
• Conjugation, binding between the antibody already bound to the molecule and a second antibody, which is linked to an enzyme
• Detection, color change in a substrate that reacts with the enzyme
• Quantification of the molecule, proportional to the emitted signal