title: The potential of spectral and hyperspectral-imaging techniques for bacterial detection in food: A case study on lactic acid bacteria.
abstract: Official methods for the detection of bacteria are based on culture techniques. These methods have limitations such as time consumption, cost, detection limits and the impossibility to analyse a large number of samples. For these reasons, the development of rapid, low-cost and non-destructive analytical methods is a task of growing interest. In the present study, the capability of spectral and hyperspectral techniques to detect bacterial surface contamination was investigated preliminarily on gel cultures, and subsequently on sliced cooked ham. In more detail, two species of lactic acid bacteria (LAB) were considered, namely Lactobacillus curvatus and Lactobacillus sakei, both of which are responsible for common alterations in sliced cooked ham. Three techniques were investigated, with different equipment, respectively: a macroscopic hyperspectral scanner operating in the NIR (10,470-5880cm(-1)) region, a FT-NIR spectrophotometer equipped with a transmission arm as the sampling tool, working in the 12,500-5800cm(-1) region, and a FT-MIR microscopy operating in the 4000-675cm(-1) region. Multivariate exploratory data analysis, in particular principal component analysis (PCA), was applied in order to extract useful information from original data and from hyperspectrograms. The results obtained demonstrate that the spectroscopic and imaging techniques investigated can represent an effective and sensitive tool to detect surface bacterial contamination in samples and, in particular, to recognise species to which bacteria belong.
authors.affiliation: University of Modena and Reggio Emilia, Department of Life Sciences, Via Amendola 2, 42122 Reggio Emilia, Italy.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Foca
authors.affiliation: University of Modena and Reggio Emilia, Department of Life Sciences, Via Amendola 2, 42122 Reggio Emilia, Italy.
authors.forename: Carlotta
authors.initials: C
authors.lastname: Ferrari
authors.affiliation: University of Modena and Reggio Emilia, Department of Life Sciences, Via Amendola 2, 42122 Reggio Emilia, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ulrici
authors.affiliation: University of Bologna, Ravenna Campus, Microchemistry and Microscopy Art Diagnostic Laboratory (M2ADL), Via Guaccimanni 42, 48100 Ravenna, Italy.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Sciutto
authors.affiliation: University of Bologna, Ravenna Campus, Microchemistry and Microscopy Art Diagnostic Laboratory (M2ADL), Via Guaccimanni 42, 48100 Ravenna, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Prati
authors.affiliation: National Research Council, Institute of Sciences of Food Production (CNR-ISPA), Via Celoria 2, 20133 Milano, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Morandi
authors.affiliation: National Research Council, Institute of Sciences of Food Production (CNR-ISPA), Via Celoria 2, 20133 Milano, Italy.
authors.forename: Milena
authors.initials: M
authors.lastname: Brasca
authors.affiliation: National Research Council, Institute of Sciences of Food Production (CNR-ISPA), Via Amendola 122/O, 70126 Bari, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Lavermicocca
authors.affiliation: University of Genova, Department of Pharmacy, Via Brigata Salerno 13, 16147 Genova, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Lanteri
authors.affiliation: University of Genova, Department of Pharmacy, Via Brigata Salerno 13, 16147 Genova, Italy. Electronic address: oliveri@dictfa.unige.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Oliveri
mesh_terms: D005504:Food Analysis; D005516:Food Microbiology; D005519:Food Preservation; D019344:Lactic Acid; D007778:Lactobacillus; D008461:Meat Products
chemical_list: D019344:Lactic Acid
keywords: Cooked ham; FT-IR microscopy; FT-NIR spectroscopy; Hyperspectral imaging; Lactic acid bacteria (LAB); Principal component analysis (PCA)