Water-soluble fluorescence nanomaterials are widely applied for water-phase food safety monitoring. However, there is still a challenge for the development of oil-soluble fluorescence nanomaterials for oil-phase food safety detection. Particularly, the edible oil quality has a huge impact on human health, in which excessive acid number (AN), 3-chloro-1,2-propanediol (3-MCPD), and moisture content (MC) are critical monitoring factors. Herein, orange-emitting oil-soluble CsPbBr1.5I1.5 quantum dots (QDs) were prepared and applied for AN and 3-MCPD detection depending on fluorescence quenching and wavelength shifts. A “turn-off” fluorescence sensor and “wavelength-shift” fluorescence colorimetric sensor were fabricated for AN and 3-MCPD detection. Water-sensitive mesoporous silica-coated CsPbBr1.5I1.5 QDs were employed for the establishment of ratiometric fluorescence sensors for MC monitoring by introducing water-stable green-emitting CsPbBr3 nanosheets (NSs) as reference probes. Perovskite nanomaterial-engineered multiplex-mode fluorescence sensors were proposed for the detection of AN, 3-MCPD, and MC in edible oil, with the limits of detection (LODs) of 0.71 mg KOH/g, 39.8 μg/mL 3-MCPD, and 0.45% MC, respectively. This work not only expands the application of perovskite nanomaterials in the bioanalysis field but also provides new materials and novel approaches for the multiplex-mode oil-phase food safety monitoring.

The accurate detection of Staphylococcus aureus enterotoxins (SEs) is vital for food safety owing to their high pathogenicity, which may be performed with surface-enhanced Raman scattering (SERS) if SERS-active nanostructures are used. Herein, a Au−Ag Janus nanoparticle (NPs)/perovskite compositeengineered SERS immunoassay was developed for SEC detection. Plasmonic Au−Ag Janus NPs demonstrated inherent SERS activity from the 2-mercaptobenzoimidazole-5-carboxylic acid ligands. CsPbBr 3 @mesoporous silica nanomaterials (MSNs) were prepared and transformed into CsPb 2 Br 5 @MSNs in the aqueous phase. Paired SEC antibody−antigen-driven plasmonic Au−Ag Janus NP-CsPb 2 Br 5 @MSN composites were prepared. They showed amplified SERS activity, attributed to the depressed plasmonic decay due to electromagnetic field enhancement and the electron transfer mechanism. A positive relationship was established between SERS signals of composites and the SEC concentration. An additive-free SERS immunoassay was developed for simple, sensitive, and reproducible SEC detection. This study will be extended to develop multiple additive-free SERS-active plasmonic NP/ perovskite composites that will open up the possibility of exploring more SERS detection probes for food safety monitoring.

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Trace staphylococcal enterotoxin C (SEC) in food poses a serious risk to human health, and it is vital to develop a sensitive and accurate approach for SEC monitoring. Herein, a surface-enhanced Raman scattering (SERS) aptasensor was developed for the quantitative detection of SEC. SERS-active gold–silver Janus@gold nanoparticles (Au–Ag Janus@Au NPs) were prepared and showed tunable solid and hollow nanostructures by simply controlling the pH values of the reaction system. Solid Au–Ag Janus@Au NPs exhibited intrinsic and enhanced SERS activity due to the intense plasmonic coupling effect between Au dots and Au–Ag Janus NPs, which was 2.27-fold and 17.46-fold higher than that of Au–Ag Janus NPs and hollow Au–Ag Janus@Au NPs, respectively. The attachment of multiple Au dots also protected Ag islands from oxidization, which increased the stability of Au–Ag Janus@Au NPs. Solid Au–Ag Janus@Au NPs served as a label-free, strong, and stable SERS detection probe and achieved sensitive and reliable detection of SEC. The limit of detection was as low as 0.55 pg/mL. This study will expand the application prospects of label-free SERS detection probes in complex systems for food safety monitoring.

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