Evaluation of food additives to control?Monilinia fructigena in apples

The agricultural sector plays a fundamental role in Morocco?s economic activities. Likewise, it makes a substantial contribution to the nation?s development since it accounts for 20% of the gross domestic product and employs around 40% of the working-age population [1]. The apple tree (Malus domestica) is a highly significant agricultural species in Morocco. Currently, it covers 32,000 ha, accounting for nearly 25% of the total fruit-bearing surface of the Rosaceae family. The cultivation of apple trees has experienced rapid growth, driven by a thriving market, an expanding range of varieties, and a dynamic industry [2]. The main areas of apple plantations in Morocco are Meknes, Midelt, Khenifra, Haouz Marrakech, Fes, and Ouarzazate [2]. The Royal Gala variety is largely planted in cropping areas, such as Imouzzer-Kandar [3]. Apple fruits have worldwide demand, not limited to Morocco, making Malus pumila Mill a globally significant tree fruit worldwide [4]. It is a nutritionally important crop that is primarily consumed as fresh fruit, sought after by consumers for its flavor and nutritional qualities. Many countries have emerged as leaders in the production of apple fruit. The Russian apple market generates about 2.6?4.3 million tons of apples per year [5]. However, a limited percentage of apples is processed into jellies, cooked slices, and juices. Monilinia fructigena affecting appleMany fungi, including Monilinia fructigena, which causes brown rot disease and large economic losses even during storage, can infect this fruit and produce fungal infections. Pome and stone fruits are susceptible to brown rot disease, which can also lead to leaf blight and blossom [6]. Apple fruits are affected by different species of brown rot, either by M. fructigena or Phytophthora syringe, as described by Giraud and Bompeix [7]. Brown rot is among the most serious diseases of apples during storage and can lead to significant losses in the orchard during preharvest. For example, in the UK, losses of apples due to brown rot disease caused by M. fructigena are estimated to be up to 22% [8]. In general, postharvest fruit loss caused by plant pathogenic fungi accounts for more than 50% of all fruit and vegetable agricultural products [9]. Fungi of the genus Monilinia are present worldwide and cause economically important damage [10]. Several Moniliia species responsible for brown rot disease [11] affect pome and stone fruits economically, both in pre- and postharvest conditions. Brown rot, caused by three species of the Monilinia, mainly M. laxa, (Aderh & Rulh) Honey, M. fructigena Honey in Whetzel, and M. fructicola (Win) Honey, is the major disease in the European Mediterranean stone fruit production regions, including Spain [12]. The disease can reach a high incidence, leading to significant losses during storage [13,14]. M. fructigena, one of the three species, is one of the most important fungal pathogens that causes brown rot in apples and heavily affects fruit production [13]. The pathogen is frequently found in Europe and Asia [10]. For instance, M. fructigena is the predominant causal agent of brown rot disease in Serbia (76.48%) [15]. The majority of fruit losses during storage are caused by diseases due to different microbial infections, leading to 25?50% fruit deterioration [16]. Control of MoniliaThe disease is mainly controlled by synthetic fungicides. However, fungicides are harmful to human health and affect negatively the environment [17]. In addition to satisfying the increasing demand for food supplies, the food industry sector has prioritized consumer health and safety [18]. In this regard, the only available treatment for managing this disease is through field fungicide spraying. However, it is unfortunate that no chemicals are allowed in the EU after the harvest of stone fruit [19]. Therefore, the use of these synthetic pesticides should be reduced. Many chemicals classified as GRAS have been used to extend fresh fruit shelf life during storage, such as bicarbonate, calcium carbonate, and silicate [17]. These organic and inorganic salts were also found to be quite promising [20]. To increase the effectiveness of electrolysis and replace the use of NaCl, which is known to produce corrosive by-products that harm equipment, operators, and consumers, several organic and inorganic salts were evaluated in the past. Among these salts was sodium bicarbonate (NaHCO3), a food additive which is used in various commodities [13]. It has also been reported to be effective in preventing postharvest diseases in a wide range of fruit. It is widely used in the food industry as a food additive and is allowed with no restrictions for many applications under European and North American regulations [21].?Moreover, SBC is a very attractive alternative because it is readily available, inexpensive, and has little risk of phytotoxicity at low concentrations (1?4%) [12]. Interestingly, trisodium phosphate (TSP), which is defined as a GRAS substance by the US Food and Drug Administration, can reduce brown rot disease and inhibit M. fructicola growth [17]. This inorganic compound is highly soluble in water and produces alkaline solutions.The researchOur study aimed to evaluate the innovative biological and integrated approaches to control brown rot disease in apples by investigating the impact of different food additives (GRAS) such as magnesium, sodium, sulphate anhydrous, ammonium carbonate, ammonium bicarbonate, copper sulphate, and other salts on the development of M. fructigena both in in vitro and in vivo trials. Therefore, we studied the effect of salts on the mycelial growth of the pathogenic fungus, the inhibition of spore germination, and the effect of different treatments on germ tube elongation. In the in vivo experiments, the severity and incidence of the disease on artificially infected fruits as affected by salt treatments were assessed. In addition, different indices of fruit quality, such as weight loss, titratable acidity, total soluble balances, and firmness were recorded. The treatments showing a high inhibition rate and low severity were then evaluated in a semi-commercial trial at two different temperatures, 22 and 4 ?C. AbstractA set of commonly used food additives was evaluated for their antifungal activity against the brown rot disease of fruits caused by the fungal pathogen Monilinia fructigena, which is one of the most economically important agents, causing important damage to pome fruits, such as pears and apples. The radial mycelial growth of the fungal pathogen was assessed in PDA amended with different concentrations (0.5, 2, 2.5, and 5%) of each additive. The results underlined that most of the additives displayed a significant inhibition of mycelial growth, with the extent of inhibition varying depending on the specific additive and concentration used. Five food additives showed high inhibition rates (above 88%), of which sodium bicarbonate, sodium carbonate, copper sulphate, and sodium hydroxide were the most effective, whereas ammonium carbonate, magnesium chlorite, and citric acid were the least effective. Interestingly, the coatings containing sodium bicarbonate, copper sulphate, and ammonium bicarbonate significantly reduced the incidence of brown rot disease in apples, but other additives were not effective, such as ammonium carbonate and magnesium sulphate. The anhydrous sodium sulphate used at a concentration of 2%, was found to be one of the least effective additives, with a reduction rate of 20%. Subsequently, food additives showing good growth inhibition rates and reduction in disease severity were then tested in semi-commercial trials at temperatures of 4 ?C and 22 ?C. The results indicated that these additives demonstrate effectiveness in controlling M. fructigena at specific concentrations, and lower temperatures (4 ?C) can improve the efficiency of the control measures. In addition, the selected food additives exhibited significant antimicrobial activity against M. fructigena, suggesting their application as a promising alternative for managing brown rot disease in apple fruits.Picture is Fig 4 of the original source -?The symptoms of brown rot disease on apple fruit as affected by different salt treatments at 22 ?C and 10 days post-inoculation. (A) Untreated control, (B) Potassium silicate 0.5%; (C) Ammonium carbonate 0.5%; (D) Ammonium bicarbonate 0.5%; (E) Sodium hydride 2%; (F) Sodium phosphate dibasic 2%; (G) Ammonium bicarbonate 2%; (H) Sodium acetate 2%; (I) Sodium carbonate 2%; (J) Sodium hydroxide 2.5%; (K) Ammonium bicarbonate 2.5%; (L) Copper sulphate 2%; (M) Sodium carbonate 2.5%; (N) Magnesium sulphate 2.5%; and (O) Copper SourcesEvaluating Food Additives Based on Organic and Inorganic Salts as Antifungal Agents against Monilinia fructigena and Maintaining Postharvest Quality of Apple FruitNadia Lyousfi, Ikram Legrifi, Nabil Ennahli, Abdelali Blenzar, Said Amiri, Salah-Eddine Laasli, Nadia Handaq, Zineb Belabess, Essaid Ait Barka & Rachid LahlaliJoF Volume 9 Issue 7 10.3390/jof9070762 https://www.mdpi.com/2309-608X/9/7/762?