Food losses, defined as a reduction in the quantity and quality of food during production and storage, impact food safety and security. Losses caused by plant pathogens are among the most significant. Chemical pesticides have been extensively used to prevent microbial diseases. Their toxicity and reduced efficacy, however, have encouraged investigators to develop alternatives. Alternatives based on microbial biopesticides tend to be safer and more environmentally benign than conventional pesticides. In recent years, formulations based on biopesticides have progressively increased in number and diversity and have attracted commercial interest. Understanding the mechanisms by which biopesticides control the disease is fundamental to achieving optimal disease control. Biocontrol mechanisms can be divided into two main categories: those related to the ability to inhibit pathogens or their virulence factors, and those that enhance host plant fitness and induce disease resistance. Here, the first type of strategy is reviewed, which is directly mediated by physical contact between biocontrol agents and pathogens or indirectly by exposure of a pathogen to antimicrobial or microbial-inhibiting compounds produced by the microbial antagonist. Mechanisms involving physical contact include mycophagy, destruction of pathogenic bacteria by bacteriophages or predation, and disease inhibition by topical applications of specific dsRNA. Indirect mechanisms that do not involve direct contact with a pathogen include the production of antimicrobial compounds, competition, and virulence factor suppression by quorum quenching. These topics are reviewed and discussed.

Winter squash “type butternut” is harvested in physiological ripening for better commercial distribution, when sensory and/or nutritional quality is not optimum for consumption. The objective of this study was to quantify the content of α-carotene, β-carotene, color and dry matter in the pulp of raw and microwave-cooked winter squash “type butternut” (variety CosmoF1) in three states of commercial maturity. Immature, mature, and very mature fruit, defined at the time of the harvest by the percentage of orange peel and green stalk, were evaluated. The highest concentration of carotenes (α-carotene + β-carotene) in mg.100 g⁻¹ pulp wet basis was found in very mature fruits (31.96 mg), followed by mature fruits (24.65 mg), and immature fruits (18.82 mg). Microwave cooking caused the loss of β-carotene (28.6% wet basis) and α-carotene (34.1%). Cooking promote a greater reduction of α-carotene in immature (40.3%) and mature (34.5%) fruits. The ratio of β-carotene and α-carotene content increased with commercial maturity from 0.93 for immature fruits to 1.0 for very mature fruit, with higher ratio in cooked pulp (1.04) vs. raw pulp (0.96).

Beef production in Uruguay is based on pasture (~85%) or concentrate (~15%), resulting in differences in meat quality. The objective of this study was to compare the oxidative stability and color of beef from these two systems during refrigerated retail display. For these purposes, the Semimembranosus muscle was removed from ten Aberdeen Angus steers raised and fed on pasture (130 days prior to slaughter) and from another ten steers fed concentrate (100 days prior to slaughter), sliced. The muscles were placed in a refrigerated showcase for 3, 6, and 9 days. The contents of β-carotene, α-tocopherol, and fatty acids were determined before the meat was placed on display. Lipid and protein oxidation, color, and heme iron content were determined before and during display. The meat from pasture-fed steers had a lower intramuscular fat content (1.78 ± 0.15 vs. 4.52 ± 0.46), lower levels of monounsaturated fatty acids, a lower n-6/n-3 ratio, less lipid and protein oxidation, lower L* and a* values, and higher levels of α-linolenic acid, DHA, total n-3, β-carotene, and α-tocopherol. In conclusion, the meat from pasture-fed steers was more stable during retail display from an oxidative point of view, which may be due to its higher levels of antioxidant compounds such as β-carotene and α-tocopherol and had a healthier fatty acid profile for consumers.

Glucose content and in vitro bioaccessibility were determined in raw and cooked pulp of Arapey, Cuabé, and Beauregard sweet potato varieties, as well as Maravilla del Mercado and Atlas winter squash, after zero, two, four, and six months of storage (14 °C, 80% relative humidity (RH)). The total glucose content in 100 g of raw pulp was, for Arapey, 17.7 g; Beauregard, 13.2 g; Cuabé, 12.6 g; Atlas, 4.0 g; and in Maravilla del Mercado, 4.1 g. These contents were reduced by cooking process and storage time, 1.1 to 1.5 times, respectively, depending on the sweet potato variety. In winter squash varieties, the total glucose content was not modified by cooking, while the storage increased glucose content 2.8 times in the second month. After in vitro digestion, the glucose content released was 7.0 times higher in sweet potato (6.4 g) than in winter squash (0.91 g) varieties. Glucose released by in vitro digestion for sweet potato stored for six months did not change, but in winter squashes, stored Atlas released glucose content increased 1.6 times. In conclusion, in sweet potato and winter squash, the glucose content and the released glucose during digestive simulation depends on the variety and the storage time. These factors strongly affect the supply of glucose for human nutrition and should be taken into account for adjusting a diet according to consumer needs.

In Uruguay, the sweet potato (Ipomoea batata, Lam.) is a commonly used vegetable in the diet of the population. In the last ten years there has been a change in the varieties available in the market with different agronomic, conservation and quality characteristics, being of interest to revalue the local production from the nutritional point of view. The aim of this work was to study the evolution of specific gravity, total soluble solids, pulp color (L *, Hue, Croma), dry matter and β-carotene in raw and cooked pulp of five cultivars of sweet potatoes. The genetic material evaluated in four moments of conservation (April, June, July and September) were INIAArapey, Beauregard, INIAE9227, MoradaCRS and MoradaBlanco. INIAE9227 and Beauregard varieties (organge pulp), when cooked, had the highest content of β-carotene during the study period (12.17 and 8.59 mg/100 g fresh weight respectively). The other cultivars, with values ranging from 0.20 to 0.34 mg β-carotene /100 g fresh weight, did not differ among themselves when cooked. There was high correlation (r = 0.89) in cooked samples between orange tone and content of β-carotene. An intake of 100 g of cooked orange pulp cultivars, Beauregard and INIAE9227, would provide at least 80% of the daily requirement of β-carotene of and adult and 1.7 to 2.5 times the daily requirement of a child.