Reuterin, Phenyllactic Acid, and Exopolysaccharides as Main Antifungal Molecules Produced by Lactic Acid Bacteria: A Scoping Review.

The primary goal of this scoping review is to collect, analyze, and critically describe information regarding the role of the main compounds (reuterin, phenyllactic acid, and exopolysaccharides) produced by LAB that possess antifungal properties and provide some suggestions for further research. The use of lactic acid bacteria (LAB) to mitigate spoilage and extend the shelf life of foodstuffs has a long history. Recently, there has been a growing interest in the unique properties of these additions to the foodstuffs in which they are applied. In recent studies regarding biopreservation, significant attention has been given to the role of these microorganisms and their metabolites. This fascinating recent discipline aims not only to replace traditional preservation systems, but also to improve the overall quality of the final product. The biologically active by-products produced by lactic acid bacteria are synthesized under certain conditions (time, temperature, aerobiosis, acidity, water activity, etc.), which can be enacted through one of the oldest approaches to food processing: fermentation (commonly used in the dairy and bakery sectors). This study also delves into the biosynthetic pathways through which they are synthesized, with a particular emphasis on what is known about the mechanisms of action against molds in relation to the type of food.

Effect of packaging in preventing cholesterol autoxidation in milk chocolates for a higher quality and safer shelf-life.

Non-enzymatic cholesterol oxidation products (COPs) are nowadays receiving increasing attention in food technology for their potential use as biomarkers of freshness and safety in raw materials and complex food matrices, as well as markers of cholesterol oxidation during the production and shelf-life of end products. Here reported is the investigation of how long three prototype milk chocolates containing whole milk powders (WMPs) of increasing shelf-lives (i.e. 20, 120, and 180 days), could be safely stored in the market by adopting the non-enzymatic COPs as a quality markers. In addition, the protective effect of two different primary packaging, sealed and unsealed ones, in mitigating the generation of non-enzymatic COPs in three prototype milk chocolates after 3, 6, 9, 12 months of shelf-life was assessed to simulate two real storage conditions. Quantifying oxysterols' levels by mass spectrometry, the oxygen impermeable packaging (PLUS) resulted to significantly quench the non-enzymatic COPs production up to 34% as to that found in the same product but with unsealed standard packaging (STD). This study represents one practical application of non-enzymatic COPs as a reliable tool for corrective strategies to prevent food oxidation.

Presence of cholesterol oxides in milk chocolates and their correlation with milk powder freshness.

Cholesterol oxidation products (COPs) of non-enzymatic origin are mainly found in meat, fish, eggs and milk, mostly originating from the type of feeding, processing and storage. To verify the significance of COPs as biomarkers of cholesterol autoxidation and milk freshness, we quantified them in chocolates containing whole milk powders (WMPs) of increasing shelf-lives (i.e. 20, 120, and 180 days). Non-enzymatic total COPs (both free and esterified) ranged from 256.57 ± 11.97 to 445.82 ± 11.88 ng/g, increasing proportionally to the shelf-life of the WMPs, thus reflecting the ingredients' freshness. Based on the expected theoretical COPs, the effect of processing was quantitatively less significant in the generation of oxysterols (41-44%) than the contribution of the autoxidation of the WMPs over time (56-59%), pointing to the shelf-life as the primary determinant of COPs. Lastly, we quantified COPs of major commercial milk chocolates on the Italian market, which followed a similar distribution (from 240.79 ± 11.74 to 475.12 ± 12.58 ng/g). Although further replications of this work are needed, this study reports preliminary results and a practical example of a first application of non-enzymatic COPs as markers to further quantify and characterize the nutritional quality and freshness, not only of ingredients but also of composite products.

Effect of gaseous ozone treatments on DON, microbial contaminants and technological parameters of wheat and semolina.

Deoxynivalenol (DON) is an important mycotoxin produced by several species of Fusarium. It occurs often in wheat grain and is frequently associated with significant levels of its modified form DON-3-glucoside (DON-3-Glc). Ozone (O3) is a powerful disinfectant and oxidant, classified as GRAS (Generally Recognised As Safe), that reacts easily with specific compounds including the mycotoxins aflatoxins, ochratoxin A, trichothecenes and zearalenone. It degrades DON in aqueous solution and can be effective for decontamination of grain. This study reports the efficacy of gaseous ozone treatments in reducing DON, DON-3-Glc, bacteria, fungi and yeasts in naturally contaminated durum wheat. A prototype was used to dispense ozone continuously and homogeneously at different concentrations and exposure time, in 2 kg aliquots of durum wheat. The optimal conditions, which do not affect chemical and rheological parameters of durum wheat, semolina and pasta, were identified (55 g O3 h-1 for 6 h). The measured mean reductions of DON and DON-3-Glc in ozonated wheat were 29% and 44%, respectively. Ozonation also produced a significant (p < 0.05) reduction of total count (CFU/g) of bacteria, fungi and yeasts in wheat grains.

Reduction of Aflatoxins in Apricot Kernels by Electronic and Manual Color Sorting.

The efficacy of color sorting on reducing aflatoxin levels in shelled apricot kernels was assessed. Naturally-contaminated kernels were submitted to an electronic optical sorter or blanched, peeled, and manually sorted to visually identify and sort discolored kernels (dark and spotted) from healthy ones. The samples obtained from the two sorting approaches were ground, homogenized, and analysed by HPLC-FLD for their aflatoxin content. A mass balance approach was used to measure the distribution of aflatoxins in the collected fractions. Aflatoxin B1 and B2 were identified and quantitated in all collected fractions at levels ranging from 1.7 to 22,451.5 µg/kg of AFB1 + AFB2, whereas AFG1 and AFG2 were not detected. Excellent results were obtained by manual sorting of peeled kernels since the removal of discolored kernels (2.6%-19.9% of total peeled kernels) removed 97.3%-99.5% of total aflatoxins. The combination of peeling and visual/manual separation of discolored kernels is a feasible strategy to remove 97%-99% of aflatoxins accumulated in naturally-contaminated samples. Electronic optical sorter gave highly variable results since the amount of AFB1 + AFB2 measured in rejected fractions (15%-18% of total kernels) ranged from 13% to 59% of total aflatoxins. An improved immunoaffinity-based HPLC-FLD method having low limits of detection for the four aflatoxins (0.01-0.05 µg/kg) was developed and used to monitor the occurrence of aflatoxins in 47 commercial products containing apricot kernels and/or almonds commercialized in Italy. Low aflatoxin levels were found in 38% of the tested samples and ranged from 0.06 to 1.50 µg/kg for AFB1 and from 0.06 to 1.79 µg/kg for total aflatoxins.

Food coloring agents and plant food supplements derived from Vitis vinifera: a new source of human exposure to ochratoxin A.

Grape pomaces are increasingly being used as starting material in the industrial production of plant food supplements (PFS), food coloring, and tartrates, but they are at risk of ochratoxin A (OTA) contamination, a mycotoxin with nephrotoxic and carcinogenic effects. We analyzed 24 commercial PFS and 13 food coloring samples derived from Vitis vinifera, mainly pomaces, using a HPLC-FLD method for OTA determination. OTA was found in 75% of PFS samples and 69% of food coloring samples at levels of <1.16-20.23 µg/kg and <1.16-32.00 µg/kg, respectively. The four commercial leavening agents containing tartrates were found to be negative for OTA. All eight samples collected in two distilleries that use grape pomaces and wine lees to produce tartrates and other byproducts contained OTA at levels of <1.16-240.93 µg/kg. The high incidence of OTA contamination in PFS and food coloring agents derived from V. vinifera suggests that maximum permitted level(s) should be established for this mycotoxin in these products.

Effect of almond processing on levels and distribution of aflatoxins in finished products and byproducts.

The fate of aflatoxins during processing of contaminated almonds into nougat, pastries, and almond syrup was evaluated by testing the effect of each processing step (blanching, peeling, roasting, caramelization, cooking, and water infusion) on the distribution and levels of aflatoxins. Blanching and peeling did not reduce total aflatoxins that were distributed between peeled almonds (90-93%) and skins (7-10%). Roasting of peeled almonds reduced up to 50% of aflatoxins. Up to 70% reduction of aflatoxins was observed during preparation and cooking of almond nougat in caramelized sugar. Aflatoxins were substantially stable during preparation and cooking of almond pastries. The whole process of almond syrup preparation produced a marked increase of total aflatoxins (up to 270%) that were distributed between syrup (18-25%) and spent almonds (75-82%). The increase of total aflatoxins was probably due to the activation of almond enzymes during the infusion step that released free aflatoxins from masked aflatoxins.