Fast food safety test could catch dangerous bacteria in minutes
Researchers have created a rapid detection method for a common foodborne pathogen that produces results in under an hour—far faster than traditional laboratory tests. The breakthrough could help food producers, feed manufacturers, and inspectors in developing countries identify contamination before products reach consumers, potentially reducing costly recalls and illness outbreaks.
Originaltitel: Rapid detection of enterotoxigenic Bacillus cereus by loop-mediated isothermal amplification assay from food and feed samples
En ny LAMP-metod för snabb detektion av enterotoxigene Bacillus cereus från mat- och foderprover öppnar marknaden för decentraliserad mikrobiologisk kontroll i resurssvaga regioner. Forskare vid Hajee Mohammad Danesh Science and Technology University utvecklade en assay mot tre huvudsakliga enterotoxingener — nheA, cytK och entFM — och uppnådde 10 000 gånger högre känslighet än konventionell PCR. Optimal amplifikation skedde vid 64°C under 40 minuter med detektionsgräns på 100 fg/µL genomiskt DNA. På 30 bangladeshiska fältprover (foder, mjölk, ägg) uppvisade metoden 96,1% diagnostisk känslighet och 66,7% specificitet jämfört med PCR. Studien är första tillämpningen av denna tregentryckta LAMP-panel regionalt. För diagnostikleverantörer och livsmedelskontrollmyndigheter innebär detta en väg mot snabbare, billigare säkerhetskontroll utan avancerad laboratorieutrustning — kritiskt för efterlevnad av FSSC 22000 och lokala matsäkerhetsstandarder.
Background Foodborne illnesses caused by enterotoxigenic Bacillus cereus represent a significant public health concern globally. Rapid and simple detection methods are needed, particularly in resource-limited settings where conventional laboratory infrastructure is lacking. This study aimed to develop and validate a loop-mediated isothermal amplification (LAMP) assay targeting three major enterotoxin genes ( nheA , cytK , and entFM ) for the rapid detection of enterotoxigenic B . cereus in food and feed samples from Bangladesh. Methods LAMP primers for the nheA gene were newly designed, while cytK and entFM primers were adapted from previous studies. Reaction conditions were optimized using B . cereus ATCC 14579. Analytical sensitivity was determined using serial dilutions of pure culture, spiked milk, and genomic DNA. Specificity was assessed against 20 bacterial strains, including Bacillus species and non- Bacillus foodborne pathogens. The assay was validated on 30 field samples (feed, milk, and eggs) and compared with conventional PCR. Results Optimal LAMP amplification was achieved at 64°C for 40 min. The limit of detection was 100 fg/µL for genomic DNA, 9 × 10 2 CFU/mL for pure culture, and 9 × 10 3 CFU/mL for spiked milk—approximately 10,000-fold more sensitive than conventional PCR. The assay showed 100% specificity for enterotoxigenic Bacillus species, with no cross-amplification of non-target bacteria. In field samples, LAMP detected enterotoxin genes in 73.3% (22/30) for nheA , 53.3% (16/30) for cytK , and 80.0% (24/30) for entFM , compared to 63.3% (19/30), 40.0% (12/30), and 70.0% (21/30) by PCR, respectively. Overall diagnostic sensitivity and specificity against PCR were 96.1% and 66.7%, respectively, with substantial agreement (κ = 0.62). Conclusion Although LAMP assays for individual B . cereus toxin genes have been described previously, this study represents the first application of this specific nheA - cytK - entFM LAMP panel in the Bangladeshi food and feed context, providing a regionally relevant, field-deployable method for food safety monitoring.