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Updated: Apr 26, 2026
Loop-Mediated Isothermal Amplification for Screening Salmonella in Animal Food and Confirming Salmonella from Culture Isolation
Published on: May 20, 2020
Rapid detection of aflatoxin producing fungi in food by real-time quantitative loop-mediated isothermal amplification
Jie Luo1, Rudi F Vogel1, Ludwig Niessen1
1Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Gregor-Mendel-Straße 4, 85354 Freising, Germany.
Abstract:
Aflatoxins represent a serious risk for human and animal health. They are mainly produced by Aspergillus flavus and Aspergillus parasiticus but also by Aspergillus nomius. Three species specific turbidimeter based real-time LAMP (loop-mediated isothermal amplification) assays were developed to quantify the three species individually in conidial solutions and to define contamination levels in samples of shelled Brazil nuts, maize, and peanuts. Standard curves relating spore numbers to time to threshold (Tt) values were set up for each of the species. Assays had detection limits of 10, 100 and 100 conidia per reaction of A. flavus, A. parasiticus, and A. nomius, respectively. Analysis of contaminated sample materials revealed that the A. nomius specific real-time LAMP assay detected a minimum of 10 conidia/g in Brazil nuts while assays specific for A. flavus and A. parasiticus had detection limits of 10(2) conidia/g and 10(5) conidia/g, respectively in peanut samples as well as 10(4) conidia/g and 10(4) conidia/g, respectively in samples of maize. The real-time LAMP assays developed here appear to be promising tools for the prediction of potential aflatoxigenic risk at an early stage and in all critical control points of the food and feed production chain.
Insights
New real-time LAMP assays accurately quantify Aspergillus species, detecting aflatoxin contamination in food. These methods enable early risk prediction in food and feed production.
Area of Science:
- Food Science
- Microbiology
- Analytical Chemistry
Background:
- Aflatoxins pose significant risks to human and animal health.
- Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius are primary producers of aflatoxins.
- Accurate quantification of these fungal species is crucial for food safety.
Purpose of the Study:
- To develop and validate species-specific real-time LAMP assays for quantifying A. flavus, A. parasiticus, and A. nomius.
- To determine the contamination levels of these Aspergillus species in Brazil nuts, maize, and peanuts.
- To establish the utility of these assays for early detection of aflatoxin-producing fungi in food production.
Main Methods:
- Development of three turbidimeter-based, real-time loop-mediated isothermal amplification (LAMP) assays.
- Establishment of standard curves correlating spore counts with time to threshold (Tt) values for each species.
- Application of assays to quantify fungal contamination in shelled Brazil nuts, maize, and peanuts.
Main Results:
- Detection limits were as low as 10 conidia/g for A. nomius in Brazil nuts and 100 conidia/g for A. flavus and A. parasiticus in peanuts and maize.
- Species-specific assays demonstrated high sensitivity and specificity in quantifying fungal contamination.
- The assays successfully identified and quantified target Aspergillus species in various food matrices.
Conclusions:
- Real-time LAMP assays provide a rapid and sensitive method for quantifying specific Aspergillus species.
- These assays are valuable tools for predicting aflatoxigenic risk early in the food and feed production chain.
- The developed methods contribute to enhanced food safety and quality control measures.
