Aflatoxin M1 absorption by non-viable cells of lactic acid bacteria and Saccharomyces cerevisiae strains in Frescal cheese.

The purpose of this study was to evaluate the ability of heat-killed cells (121 °C, 10 min) from two strains of lactic acid bacteria (LAB) (Lactobacillus rhamnosus and Lactococcus lactis) and one strain of yeast (Saccharomyces cerevisiae), alone or in combination, to reduce the levels of aflatoxin M1 (AFM1) in Frescal cheese during 30 days of storage. The experimental design was totally randomized, in a 2 × 2 × 2 factorial arrangement, corresponding to two levels of LAB (0 and L. rhamnosus at 1010 cells/kg + L. lactis at 1010 cells/kg), two levels of S. cerevisiae in milk (0 and 1010 yeast cells/kg) and two AFM1 levels (0 and 0.5 µg/kg) added to the cheese curd, totaling 8 treatments with three replicates per treatment. AFM1 levels in Frescal cheese were evaluated by using a high-performance liquid chromatography. Cheese fat and protein contents were not affected (P > 0.05) by any of the treatments, and only pH decreased (P < 0.05) in all treatments from days 2 to 30 of storage (usual shelf life of this type of cheese). AFM1 levels detected in contaminated cheeses decreased on day 2 of storage, varying from 0.09 µg/kg (cheese with addition of bacterial cells) to 0.29 µg/kg (no addition of LAB or yeast cells), this may have occurred due to loss of AFM1 in the Frescal cheese whey. The concentrations of detected AFM1 decreased (P < 0.05) in all treatments from days 2 to 10 of storage, and the maximum percentage reduction of the detectable levels (100%) was achieved after 10 and 20 days of storage in cheeses containing LAB and yeast cells, or prepared with yeast cells alone, respectively. The addition of heat-killed LAB (cells of L. rhamnosus and L. lactis) and Saccharomyces cerevisiae alone or in combination, has a potential ability for adsorbing the AFM1 in Frescal cheese during 30 days of storage.

The concentration and prevalence of ochratoxin A in coffee and coffee-based products: A global systematic review, meta-analysis and meta-regression.

The current investigation was aimed to estimate the prevalence and concentration of ochratoxin A (OTA) in different types of coffee and coffee-based products with the aid of a systematic review and meta-analysis. Therefore, the recommended databases including PubMed, Scopus, and Embase from Jan 1983 to Oct 2018 were screened to retrieve the related citations. In this regard, among 1041 explored articles in the identification step, thirty six articles with 3182 samples were included in the meta-analysis and meta-regression. According to findings, the global pooled concentration and prevalence of OTA was calculated as 3.21 µg/kg (95% CI: 3.08-3.34 µg/kg) and 53.0 % (95% CI: 43.0-62.0), respectively. Also, direct correlations between the increases in poverty as well as the amount of annual precipitation and prevalence of OTA was noted, while with decreasing in HDI the prevalence of OTA in coffee significantly was increased. Moreover, the lowest and highest concentrations of OTA in coffee were observed in Taiwan (0.35 µg/kg) and Turkey (79.0 µg/kg), respectively. The outcome of this meta-analysis can be used for the building of risk assessment models aiming to derive data for the development of specific actions to reduce the exposure to this mycotoxin in coffee and coffee-based products.

Changes in masked forms of deoxynivalenol and their co-occurrence with culmorin in cereal-based products: A systematic review and meta-analysis.

This study was aimed to evaluate the fate of D3G, 3-ADON, and 15-ADON during various processing steps (milling, fermentation, baking and cooking with water) of different cereal-based products, as well as the co-occurrence of culmorin (CUL) and its derivatives (15-Hydroxy-CUL and 5-Hydroxy-CUL. Some databases such as Science Direct, PubMed, Scopus, and Embase were screened to collect the relevant published papers between January 1983 to October 2018, and 23 articles with 319 data were included. The baking resulted in reductions in the concentration of all types of investigated masked mycotoxins, i.e., 15-ADON (-25%) > 3-ADON (-15%) > D3G (-6%). Also, rank order of CUL and its derivatives based on occurrence was CUL (70%) > 15-Hydroxy-CUL (47%) > 5-Hydroxy-CUL (15%) and their rank based on their concentration was 5-Hydroxy-CUL (99.21 µg/kg) > CUL (48.84 µg/kg) > 15-Hydroxy-CUL (9.39 µg/kg) > Hydroxy -CUL (0.06 µg/kg) > 12-Hydroxy-CUL (0.05 µg/kg) > 14-Hydroxy-CUL (0.01 µg/kg).

Effect of peracetic acid on biofilms formed by Listeria monocytogenes strains isolated from a Brazilian cheese processing plant

ABSTRACT This study aimed to investigate the effect of peracetic acid (PAA, 0.5%) on adherent cells of three strains of Listeria monocytogenes strains belonging to serotypes 4b and 1/2b that had been previously isolated from the environment of a Brazilian cheese plant. The assays were conducted using polystyrene microplates and stainless steel coupons and the adhered cells were treated with PAA for 60, 120 and 180 s. On stainless steel, biofilms were partially inactivated by PAA after 60 s and almost 100% of the cells were damaged within 180 s using epifluorescence microscopy with LIVE/DEAD® staining. On polystyrene microplates, PAA decreased (P<0.05) biofilm biomass produced by the three L. monocytogenes isolates at 60 s, when compared with controls (no PAA treatment). However, PAA did not completely eliminate L. monocytogenes cells on polystyrene microplates (decreasing 1.8-2.5 log cycles after treatment with PAA for 180 s). The correct concentration and contact time of PAA is critical for eliminating biofilms formed by L. monocytogenes on stainless steel surfaces, although further studies are needed for defining efficient PAA treatments to remove adherent cells of this pathogen on plastic polymers