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Food detection technologies play a vital role in ensuring food safety in the supply chains. Conventional food detection methods for biological, chemical, and physical contaminants are labor-intensive, expensive, time-consuming, and often alter the food samples. These limitations drive the need of the food industry for developing more practical food detection tools that can detect contaminants of all three classes. Raman spectroscopy can offer widespread food safety assessment in a non-destructive, ease-to-operate, sensitive, and rapid manner. Recent advances of Raman spectroscopic methods further improve the detection capabilities of food contaminants, which largely boosts its applications in food safety. In this review, we introduce the basic principles of Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS), and micro-Raman spectroscopy and imaging; summarize the recent progress to detect biological, chemical, and physical hazards in foods; and discuss the limitations and future perspectives of Raman spectroscopic methods for food safety surveillance. This review is aimed to emphasize potential opportunities for applying Raman spectroscopic methods as a promising technique for food safety detection.

Campylobacter species are Gram-negative, motile, and non–spore-forming bacteria with a unique helical shape that changes to filamentous or coccoid as an adaptive response to environmental stresses. The relatively small genome (1.6 Mbp) of Campylobacter with unique cellular and molecular physiology is only understood to a limited extent. The overall strict requirement of this fastidious microorganism to be either isolated or cultivated in the laboratory settings make itself to appear as a weak survivor and/or an easy target to be inactivated in the surrounding environment of poultry farms, such as soil, water source, dust, surfaces and air. The survival of this obligate microaerobic bacterium from poultry farms to slaughterhouses and the final poultry products indicates that Campylobacter has several adaptive responses and/or environmental niches throughout the poultry production chain. Many of these adaptive responses remain puzzles. No single control method is yet known to fully address Campylobacter contamination in the poultry industry and new intervention strategies are required. The aim of this review article is to discuss the transmission, survival, and adaptation of Campylobacter species in the poultry production environments. Some approved and novel control methods against Campylobacter species throughout the poultry production chain will also be discussed.

As less consumed animal by-product, beef and pork offal have chances to sneak into the authentic ground beef meat products, and thus a rapid and accurate detection and quantification technique is highly required. In this study, Fourier transformed-infrared (FT-IR) spectroscopy was investigated to develop an optimized protocol for analyzing ground beef meat potentially adulterated with six types of beef and pork offal. Various chemometric models for classification and quantification were constructed for the collected FT-IR spectra. Applying optimized chemometric models, FT-IR spectroscopy could differentiate authentic beef meat from adulterated samples with >99% accuracy, to identify the type of offal in the sample with >80% confidence, and to quantify five types of offal in an accurate manner ( R 2  > 0.81). An optimized protocol was developed to authenticate ground beef meat as well as identify and quantify the offal adulterants using FT-IR spectroscopy coupled with chemometric models. This protocol offers a limit of detection <10% w/w of offal in ground beef meat and can be applied by governmental laboratories and food industry to rapidly monitor the integrity of ground beef meat products.

Carcinogenic Sudan I has been added illegally into spices for an apparent freshness. 1 H solution and solid-state (SS) nuclear magnetic resonance (NMR) spectroscopies were applied and compared for determination of Sudan I in paprika powders (PPs). For solution NMR, PPs spiked with Sudan I were extracted with acetonitrile, centrifuged, rotor-evaporated, and re-dissolved in DMSO-d6 for spectral collection. For SSNMR, Sudan I contaminated PPs were mixed with DMSO-d6 solution and used for spectral collection. Linear regression models constructed for quantitative analyses resulted in the average accuracies for unknown samples as 98% and 105%, respectively. Limits of detection for the solution NMR and SSNMR spectrometers were 6.7 and 128.6 mg kg −1 , while the limits of quantification were 22.5 and 313.7 mg kg −1 . The overall analysis time required by both methods was similar (35 and 32 min). Both NMR techniques are feasible for rapid and accurate determination of Sudan I adulteration in PPs.

The increase in the concentration of CO 2 in the atmosphere has attracted widespread attention. To explore the effect of elevated CO 2 on lettuce growth and better understand the mechanism of elevated CO 2 in lettuce cultivation, 3 kinds of lettuce with 4 real leaves were selected and planted in a solar greenhouse. One week later, CO 2 was applied from 8:00 a.m. to 10:00 a.m. on sunny days for 30 days. The results showed that the growth potential of lettuce was enhanced under CO 2 enrichment. The content of vitamin C and chlorophyll in the three lettuce varieties increased, and the content of nitrate nitrogen decreased. The light saturation point and net photosynthetic rate of leaves increased, and the light compensation point decreased. Transcriptome analysis showed that there were 217 differentially expressed genes (DEGs) shared by the three varieties, among which 166 were upregulated, 44 were downregulated, and 7 DEGs were inconsistent in the three materials. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that these DEGs involved mainly the ethylene signaling pathway, jasmonic acid signaling pathway, porphyrin and chlorophyll metabolism pathway, starch and sucrose metabolism pathway, etc. Forty-one DEGs in response to CO 2 enrichment were screened out by Gene Ontology (GO) analysis, and the biological processes involved were consistent with KEGG analysis. which suggested that the growth and nutritional quality of lettuce could be improved by increasing the enzyme activity and gene expression levels of photosynthesis, hormone signaling and carbohydrate metabolism. The results laid a theoretical foundation for lettuce cultivation in solar greenhouses and the application of CO 2 fertilization technology.

This mini-review summarizes the most recent progress concerning the use of surface-enhanced Raman spectroscopy (SERS) for the detection and characterization of antibiotic-resistant bacteria. We first discussed the design and synthesis of various types of nanomaterials that can be used as the SERS-active substrates for biosensing trace levels of antibiotic-resistant bacteria. We then reviewed the tandem-SERS strategy of integrating a separation element/platform with SERS sensing to achieve the detection of antibiotic-resistant bacteria in the environmental, agri-food, and clinical samples. Finally, we demonstrated the application of using SERS to investigate bacterial antibiotic resistance and susceptibility as well as the working mechanism of antibiotics based on spectral fingerprinting of the whole cells.

Probiotic Lactobacillus can be used to reduce the colonization of pathogenic bacteria in food animals, and therefore reduce the risk of foodborne illness to consumers. As a model system, we examined the mechanism of protection conferred by Lactobacillus species to inhibit C. jejuni growth in vitro and reduce colonization in broiler chickens. Possible mechanisms for the reduction of pathogens by lactobacilli include: 1) stimulation of adaptive immunity; 2) alteration of the cecal microbiome; and, 3) production of inhibitory metabolites, such as organic acids. The Lactobacillus species produced lactic acid at concentrations sufficient to kill C. jejuni in vitro. We determined that lactic acid produced by Lactobacillus disrupted the membrane of C. jejuni, as judged by biophotonics. The spectral features obtained using Fourier-transform infrared (FT-IR) and Raman spectroscopy techniques were used to accurately predict bacterial viability and differentiate C. jejuni samples according to lactic acid treatment. FT-IR spectral features of C. jejuni and Lactobacillus grown in co-culture revealed that the metabolism was dominated by Lactobacillus prior to the killing of C. jejuni. Based on our results, the development of future competitive exclusion strategies should include the evaluation of organic acid production.

High temperatures compromise crop productivity worldwide, but breeding bottlenecks slow the delivery of climate-resilient crops. By investigating tomato fruit set under high temperatures, we discover a module comprising two linked genes, THERMOSENSITIVE PARTHENOCARPY 4a ( TSP4a ) and TSP4b , which encode the transcriptional regulators IAA9 and AINTEGUMENTA (ANT), respectively, to control thermosensitive parthenocarpy. TSP4a and TSP4b form a positive feedback loop upon heat stress to repress auxin signaling in ovaries. Natural TSP4a and TSP4b alleles bear regulatory-region polymorphisms and are differentially expressed to overcome the trade-off between fruit set and wider plant development. Gene editing of the TSP4a promoter and TSP4b 3’ UTR in open-chromatin regions results in expression down-regulation, increased parthenocarpy without yield penalties and maintenance of fruit-sugar levels without broad auxin-related pleiotropic defects in greenhouse-grown plants. These mechanistic insights into heat-induced parthenocarpy and auxin signaling in reproductive organs demonstrate breeding utility to safeguard tomato yield under warming scenarios. High temperature impairs tomato fruit set. Here, the authors identify the TSP4a-TSP4b module, homologous to IAA9 and AINTEGUMENTA, which promotes parthenocarpy by suppressing auxin signaling, thereby boosting yield under heat stress.

Analyzing biomolecules is essential for disease diagnostics, food safety inspection, environmental monitoring and pharmaceutical development. Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for detecting biomolecules due to its high sensitivity, rapidness and specificity in identifying molecular structures. This review focuses on the SERS analysis of biomolecules originated from humans, animals, plants and microorganisms, combined with nanomaterials as SERS substrates and nanotags. Recent advances in SERS detection of target molecules were summarized with different detection strategies including label-free and label-mediated types. This comprehensive and critical summary of SERS analysis of biomolecules might help researchers from different scientific backgrounds spark new ideas and proposals.

Food safety remains one of the most important issues in most countries and the detection of food hazards plays a key role in the systematic approach to ensuring food safety. Rapid, easy-to-use and low-cost analytical tools are required to detect chemical hazards in foods. As a promising candidate, microfluidic paper-based analytical devices (μPADs) have been rarely applied to real food samples for testing chemical hazards, although numerous papers have been published in this field in the last decade. This review discusses the current status and concerns of the μPAD applications in the detection of chemical hazards in foods from the perspective of food scientists, mainly for an audience with a background in mechanical and chemical engineering who may have interests in exploring the potential of μPAD to address real-world food safety issues.