Grape Tomatoes Research Articles

Development of pea protein-based films and coatings with haskap leaf extracts

Haskap (Lonicera caerulea) leaves are an agricultural residue from haskap farms, where haskap berries are cultivated commercially. The leaves are rich in bioactive compounds that could be beneficial for food packaging and preservation. In this study, pea protein-based films and coatings were studied as renewable packaging options for grape tomatoes and Cavendish bananas. The effect of haskap leaf extracts in the films and coatings on weight loss of the tomatoes and bananas was investigated. The bioactive leaf extracts were obtained from prior extraction experiments using either aqueous two-phase extraction (ATPE) or aqueous two-phase flotation (ATPF). The leaf extracts contained bioactive compounds, ethanol, water, and residual salt. The tomatoes and bananas were monitored for changes in weight, °Brix, and pH values over the storage time. Pea protein isolate films containing sodium phosphate/ethanol ATPE extract had the best result for tomatoes with a smaller weight loss (1.81%) compared to those stored with pea protein films containing no extract (1.92%) and without films (2.51%). However, the pea protein concentrate coatings, both with and without extracts, had no significant effect on weight loss for the bananas.

‘Mountain Bebe’: Hybrid Grape Tomato and Its Parents NC 7 Grape and NC 8 Grape

‘Mountain Bebe’: Hybrid Grape Tomato and Its Parents NC 7 Grape and NC 8 Grape

Potassium and growth-promoting fungi improve the postharvest quality of grape tomato

Tomato plants respond well to potassium fertilization, whose insufficiency leads to a drop in fruit production and quality. On the other hand, the association of growth-promoting fungi (GPF) with roots has been shown to be able to optimize nutrient absorption, which implies lower financial costs and a decreased risk of loss of K applied to the soil. The objective of this study was to investigate the effects of inoculation with GPF and K rates on the postharvest quality of grape tomato hybrid ‘Mascot’ grown in a hydroponic system. The plants were cultivated in a hydroponic drip system using washed and sterilized sand as substrate. They were trained with two stems, leaving three bunches per stem. The experiment was carried out in a splitsplit-plot arrangement in a completely randomized design with three replicates. Ripe fruits were stored for 30 days in PET containers in storage chambers at a temperature of 25 °C. After 0, 10, 20 and 30 days of storage, five fruits were collected to determine the titratable acidity (TA) and soluble solids (SS), reducing sugars (RS) and vitamin C contents. The K rates provided an increase in the quality attributes. At low K rates, inoculation with GPF led to higher TA, SS, RS and vitamin C values. Inoculation of the plants with GPF improved the postharvest preservation of the fruits, especially when the plants underwent nutritional stress during cultivation.

Production and quality of Sweet Grape tomato in response to foliar calcium fertilization

In tomato, foliar application of calcium-based nutrient solutions is used to complement soil fertilization. However, knowledge regarding the factors that influence the effectiveness of foliar fertilizer applications remains incomplete. The objective of this study was to evaluate the efficiency foliar fertilization with calcium for improving production and quality of hydroponic Sweet Grape tomatoes. An experiment was conducted in a commercial hydroponic system in a split-plit-plot scheme, with two calcium doses: 1,5 and 3 mmol L-1 of Ca. The solutions were sprayed on the leaves at intervals of 7 and 14 days, using commercial foliar fertilizers containing 0.3 g L-1 of calcium chloride or calcium acetate. The results indicate that the foliar application of calcium fertilizers, regardless of the amount of calcium provided in the nutrient solution and the frequency of applications, positively affects fruit production and quality. No difference was found between the effects of application of the two calcium sources, as well as the frequency of application.

Use of By-Products from the Tequila Industry. Part 12: Composted Agave Bagasse for Growing Grape Tomatoes

Here, we evaluated the possibility of growing grape tomatoes on three different mixtures of composted agave bagasse substrate. Tomatoes were grown in 28-L pots for 106 days under a drip irrigation system with a hydroponic crop nutrient solution. The average production of grape tomatoes was 338.9, 358.9, and 325.7 g/pot/cut for each of the substrates studied, and no significant difference was observed between treatments (p > 0.5). The mean of numbers of grape tomatoes were 34.6, 38.8, and 34.2/pot/cut for each of the substrates studied, and no significant difference was observed between treatments (p > 0.5). The mean weight of individual grape tomatoes was about 10.4 g for all of the substrates tested. These results confirmed the notion that a composted agave bagasse substrate could replace an expensive imported substrate. The remaining challenge is to produce agave bagasse substrate commercially, because to date, agave bagasse substrates have only been produced on a pilot scale for testing. Therefore, it is necessary to implement a stabilized process for producing agave bagasse at a commercial level. This process must consider economic production costs and market value to ensure that the product is competitive with other substrates typically used in soilless crops.

Antioxidant and anti-proliferative activity of free, conjugates and bound phenolic compounds from tomato and industrial tomato by-product.

The aim of this study was to evaluate the antioxidant and anti-proliferative activity of different fractions of phenolic compounds from tomato and tomato by-product. Soluble free phenolics and bound phenolics (BP) fractions from saladette tomato and industrial tomato by-product as well as, conjugated acid-hydrolysable phenolics (AHP) and alkaline-hydrolysable phenolics (AKHP) from saladette tomato, grape tomato and industrial tomato by-product, were tested. The scavenging effects of phenolic fractions on superoxide anion were determined using the PMS-NADH-NBT system. The myoglobin protection ratios of samples against hydroxyl radical were evaluated and the anti-proliferative effects in the MCF-7 breast cancer cell line were determined. AHP fraction from tomato by-product and AKHP fraction from grape and saladette tomato showed the highest inhibitory capacity of the superoxide anion (p ≤0.05). All samples had a myoglobin protection ratio from 30 to 50%. Regarding to cytotoxicity assays, all phenolic fractions from tomato by-product, as well as, BP, AHP, AKHP from saladette tomato and AHP from grape tomato showed important anti-proliferative activity against MCF-7 breast cancer cell line (IC50 <20μg/mL). From the results, we can conclude that tomato and tomato by-product are a good source of natural compound with important antioxidant and anti-proliferative activity.

Genome Wide Analysis of GH Gene Family Reveals Vvgh9 Positively Regulates Sugar Accumulation under Low Sugar Content in Grape

Sugar content directly affects grape (Vitis vinifera L.) berry quality and the resulting wine. Therefore, it is of great importance to study and explore novel genes that affect sugar accumulation in grapes. Glycosyl hydrolases (GHs) are key enzymes hydrolyzing polysaccharides into monosaccharides and play important roles in the regulation of carbohydrate metabolism. Nevertheless, the impact of GHs on the regulation of sugar accumulation in plants has rarely been investigated. In this study, we identified 11 putative GH genes in grapevines by phylogeny analysis. RNA-seq and quantitative real-time PCR results demonstrated that the expression level of VvGH9 was higher during the fruit set stage, which had lower sugar content than the véraison and ripe stages. Treatment of grape berries with exogenous sugar two weeks before véraison revealed that VvGH9 was rapidly induced by sucrose, fructose, and glucose. When ‘41B’ calli was treated with different concentrations of glucose, VvGH9 expression increased at first and then decreased with the increase of glucose concentration. Overexpression of VvGH9 in grape calli and tomatoes also confirmed that this gene could contribute to sugar accumulation. All the above results demonstrated that VvGH9 promotes sugar accumulation under low sugar content in plants.

Application of dielectric barrier discharge for improving food shelf life and reducing spoilage

Dielectric Barrier Discharge (DBD) based ozone therapy is an attractive non-thermal, additive-free and environment-friendly alternative to traditional food processing technologies. Its practical application is dependent on economical ozone generation and optimum ozone dosage. This study investigates the one-time and periodic application of a compact (48 cu. cm), lightweight (55 g), low power, low temperature, DBD ozone generator for treatment of spoilage inocula prepared from combinations of spoiled green beans, grape tomatoes, lettuce and strawberries. A one-time exposure of 126–136 ppm of average ozone concentration produced by the DBD generator over 3 min and 15 min resulted in at least 1 and 4 log reduction, respectively, in microbial colonies present in the spoilage inocula. Daily exposure of 128.7 ppm average ozone concentration over 3 min under similar conditions showed that inhibition through periodic exposure can successfully inhibit the growth of both bacteria and mold species with at least 5 log reduction of microbial colonies. Visual inspection of whole fruits and vegetables with similar 3-min daily exposure showed the potential of ozone therapy to at least double the shelf-life of food products. For the daily exposures, energy required by the DBD ozone generator was calculated as 0.39 pm 0.06 kJ/day.

Air microbubble assisted washing of fresh produce: Effect on microbial detachment and inactivation

Chlorine based sanitizers are used during fresh produce washing to reduce microbial cross-contamination. However, the antimicrobial effectiveness of these sanitizers on pathogens attached to produce surface is limited. Therefore, we evaluated ability of air microbubbles to detach and inactivate bacteria from fresh produce and generate sub-lethal stress within bacteria to increase their susceptibility to sodium hypochlorite, thus improving latter’s efficacy. At tested levels, air microbubbles did not cause damage to E. coli O157:H7 cell membrane or intracellular oxidation. Compared to water, microbubble-assisted washing had no improvement on bacterial detachment from grape tomatoes, blueberries, and baby spinach. Microbubble-assisted washing resulted in 3.3 ± 0.1, 0.8 ± 0.5, and 1.0 ± 0.4 log CFU/g reduction from grape tomatoes, blueberries, and baby spinach surface when used together with 100 mg/L sodium hypochlorite, indicating the role of produce surface properties on bacterial inactivation. However, these reductions were not significantly different from that obtained by washing these samples with 100 mg/L sodium hypochlorite in the absence of microbubbles (P > 0.05), indicating that air microbubbles did not increase the efficacy of sodium hypochlorite. Interestingly, microbubble assisted washing significantly increased (P < 0.05) soil removal from baby spinach, with the turbidity of sonicated water, which represented the soil content remaining on produce following washing (with or without microbubbles) process, reduced from 52.9 ± 11.5 (control) to 14.3 ± 2.4 NTU, compared to 31.0 ± 7.7 NTU for water washed samples. At tested conditions, air microbubbles may have limited effect on detachment and inactivation of bacteria in the presence of sanitizers, but they can improve cleaning efficacy of washing processes.

Growth, fruit yield, quality, and water productivity of grape tomato as affected by seed priming and soil application of silicon under drought stress

Drought has been identified as a major threat restricting crop production worldwide. Silicon (Si), a beneficial element, has a proven role in enhancing plant tolerance against various biological and environmental stresses, especially drought. Two polyhouse experiments were conducted to evaluate the effect of seed priming and soil application of Si on growth, fruit yield, quality, and water productivity of grape tomato (Solanum Lycopersicon L. var. cerasiform) under drought stress. In the first experiment, Si in the form of monosilicic acid (MSA [H4SiO4]) was applied as a seed priming material in five doses (0, 0.063, 0.125, 0.25, and 0.5 mM) under three soil moisture regimes (50%, 75%, and 100% field capacity [FC]). The second experiment consisted of five MSA doses applied as soil incorporation (0, 75, 150, 300, and 600 kg ha–1) under the same soil moisture regimes used in the first experiment. The results revealed that fruit yield and irrigation water productivity were severely affected by soil moisture deficit at 50% FC, while fruit quality was better at this soil moisture level. Fruit yield was reduced by 95% at 0 mM MSA priming dose at 50% FC compared with fruit yield at 0.25 mM MSA priming dose at 100% FC in the first experiment. In the second experiment, soil incorporation of MSA at 300 kg ha–1 in combination with 100% FC maximized fruit yield, which was reduced by 96% at 0 kg ha–1 MSA dose in combination with 50% FC. Exogenous application of MSA at 0.25 mM as a seed priming material and 300 kg ha–1 as soil incorporation (60 kg ha–1 soluble Si) also resulted in better fruit yield and irrigation water productivity at 75% FC. Priming seeds of grape tomato with MSA at 0.25 mM or soil incorporating with 300 kg ha–1 could be recommended to enhance fruit yield of grape tomato grown under soil moisture regime fluctuating between sufficient (100% FC) and moderate soil moisture availability (75% FC).

Factors Impacting Chemical and Microbiological Quality of Wash Water during Simulated Dump Tank Wash of Grape Tomatoes

Fresh and fresh-cut tomatoes are high in phytonutrients. However, illness outbreaks associated with contaminated tomatoes have significantly impacted public health and the economic well-being of the tomato industry. Scientific information is needed to develop an effective, practical food safety standard to reduce pathogen contamination. The aim of this study was to assess factors impacting the deterioration of the quality of tomato wash water and the proliferation of indigenous microorganisms during a simulated dump tank washing process. Freshly harvested grape tomatoes were sorted into four groups: prime, defective, underripe, and nontomato debris. Tomatoes with leaf or stem harvest debris, combined or separate, were washed in tap water with or without free chlorine. Water samples were analyzed for total dissolved solids, turbidity, chemical oxygen demand, and chlorine demand. Microbial populations in water and on tomatoes as impacted by chlorine concentration and water filtration (300 μm) were also quantified. Field debris and defective tomatoes were the major contributors to microbial populations in wash water. Field debris, although accounting for <1% of the total weight of harvested material, contributed 37.84% of total dissolved solids, 46.15% of turbidity, 48.77% of chemical oxygen demand, and 50.55% of chlorine demand in the wash water. Water quality deterioration was proportional to the cumulative quantity of tomatoes and debris washed, and free chlorine at ≥5 mg/L significantly reduced the Enterobacteriaceae, aerobic mesophilic bacteria, and yeast and mold populations. These results highlight the importance of minimizing field debris and defective fruits in harvested grape tomatoes to reduce the microbial load and prevent deterioration of wash water quality. This information will be useful for the development of data-driven harvesting and packinghouse food safety practices for grape tomatoes.

Physicochemical properties and shelf-life of raw and cooked patties added with various levels of grape tomato powder by different drying methods

The objective of this study was to investigate antioxidant activities of various grape tomato powder (GTP) and then 0.25 and 0.5% oven-dried and freeze-dried GTP were applied to raw and cooked pork patties to investigate their physicochemical properties, texture, antioxidant activities, and antimicrobial activities. Oven-dried GTP dried at 100 °C had the highest 1,1-diphenyl-2-pycrylhydrazyl (DPPH) scavenging activity, ferric reducing power ability (FRPA), ferrous iron chelating activity (FICA) and total phenolic contents (TPCs) except for reference. pH and microbial counts of raw patties decreased after GTP was added. Raw and cooked patties showed decreases of 2-thiobarbituric acid reactive substances (TBARS), lightness values, and volatile basic nitrogen (VBN) values, while their redness and yellowness showed increases after the addition of GTP. Enterobacteriaceae did not show any growth for cooked treatments during storage. Addition of GTP improved antimicrobial and antioxidant activities of pork patties, and 0.5% oven-dried GTP showed the highest antioxidant activities among treatments during storage.

Preservation of grape tomato by isochoric freezing

This study investigated the potential of isochoric freezing to preserve tomatoes. Isochoric freezing is an emerging technology that preserves biological matter at subfreezing temperatures without any ice damage. Isochoric freezing was compared with freezing under isobaric conditions and with preservation techniques used in the food industry: cold storage at 10 °C and individual quick freezing (IQF). Physicochemical and nutritional properties were evaluated weekly for four weeks. Preservation under isochoric conditions maintained the mass, color, nutrient content (ascorbic acid, lycopene and phenolics) and antioxidant activity of the fresh tomatoes. Also, isochoric preservation led to minimal texture damage. In comparison, mass loss of tomatoes stored at 10 °C for 3 weeks contributed to changes in overall visual quality and firmness as well as significant losses in nutrient content. The greatest mass, texture, and nutrients losses were obtained for tomatoes subjected to IQF and isobaric freezing. The results show that isochoric freezing has the potential to preserve tomatoes while maintaining physicochemical and nutritional properties similar to those of fresh tomatoes which might find application in the commercial preservation of tomatoes.

Effects of fish-derived protein hydrolysate, animal-based organic fertilisers and irrigation method on the growth and quality of grape tomatoes

ABSTRACT Agriculture needs to supply food for a growing population whilst also minimising the environmental impact, and the adoption of sustainable agriculture systems has been proposed as a solution to achieve this. The objective of this study was to evaluate the effects of seven fertilisation treatments (FT1-FT6 organic fertilisers, FT7 conventional fertiliser) and two irrigation methods (drenching and non-recirculating subirrigation (NRS)) on plant growth, yield, fruit quality and polyphenol concentrations in grape tomatoes. For plants irrigated by drenching, leaf dry weight (dw), total plant biomass dw, fruit number and total yield were higher in the organic fertilisation treatment FT6 (including fish-derived protein hydrolysate as an N-source), surpassing the conventional treatment (FT7) by 35%, 9%, 21%, and 4% for these parameters, respectively, though the difference was only significant for leaf dw. For plants grown with NRS, the total yield in FT7 was higher than that in any of the organic fertiliser treatments. In the organic treatments FT1, FT3 and FT4 the tomatoes had higher total soluble solids concentrations than the fruit in FT7. With drench irrigation, the concentrations of total hydrolysable polyphenols were highest in FT2, FT5 and FT7, but with NRS, it was highest is FT2. With drenching, the concentration of total condensed polyphenols was highest in FT1, whereas with NRS it was similar in all fertilisation treatments. The results indicated that for the production of grape tomatoes, adding fish-derived protein hydrolysates and using the subirrigation system can help reduce the gap between the yields of organic and conventional systems.

Foliar application and seed priming of salicylic acid affect growth, fruit yield, and quality of grape tomato under drought stress

Drought, an acute abiotic stress, limits growth and yields of crops including tomato. Salicylic acid (SA) has been widely used as an abiotic stress mitigating agent in various crops. Two experiments were conducted to assess the effects of SA applied as a foliar spray and as a seed priming material on growth, yield, and fruit quality of grape tomato under drought stress. In the first experiment, SA was applied as a foliar spray in five doses (0, 50, 100, 150, and 200 mg L–1) under three soil moisture regimes (50 %, 75 %, and 100 % field capacity [FC]). In the second experiment, doses of SA and soil moisture regimes were the same as first experiment, except that SA was applied as a seed priming material. Data on growth, fruit yield, and quality of grape tomato were collected. The results revealed that severe moisture deficit of 50 % FC adversely affected growth and fruit yield of grape tomato by 94 % in experiment 1 (foliar application of SA) and by 95 % in experiment 2 (seed priming of SA) compared with 100 % FC, while fruit quality parameters (fruit pH, total soluble solids, and color index) improved with reducing soil moisture regime. Exogenous application of SA at 150 mg L–1 as a foliar spray enhanced fruit yield by 41 % and at 100 mg L–1 as a seed priming material resulted in 33 % increase in fruit yield compared with the control. However, there was no effect of SA supplementation at severe moisture deficit of 50 % FC regardless of experiments and doses. Foliar application of SA at 150 mg L–1 resulted in statistically similar yields between moderate soil moisture level of 75 % FC and sufficient soil moisture level of 100 % FC, whereas in case of seed priming treatment, maximum fruit yield was obtained at 100 mg L–1 SA dose in combination with 100 % FC. Grape tomato yielded more with foliar application of SA (113.1 g plant–1 fruit yield at 150 mg L–1) than did with SA seed priming (87.8 g plant–1 fruit yield at 100 mg L–1). Exogenous application of SA at 150 mg L–1 as a foliar spray and at 100 mg L–1 as a seed priming material could be recommended when grape tomato is grown under moderate to sufficient soil moisture availability.

Development and evaluation of a point-of-use UV appliance for fresh produce decontamination

In-house treatment strategy for fresh produce decontamination has not been emphasized as much as industrial washing. The most common treatment for fresh produce decontamination and cleaning at home and other point-of-use places such as cafeteria is rinsing and/or soaking in a sink. In this study, an appliance utilizing UV and agitated water to decontaminate fresh produce was developed and its effectiveness was investigated in an aim to identify optimum processing parameters. Grape tomato and spinach representing two different surface smoothness were dip-inoculated in a four-strain Salmonella cocktail to reach a final population of 5–8 log CFU/g and air-dried. The produce samples were then washed in 1 gallon tap water under varying conditions, water agitation speed (0–190 RPM), sample size (50–400 g), UV intensity (0–30 mW/cm2) and treatment time (2, 5 and 10 min). In general, increasing the agitation speed and UV intensity enhanced Salmonella inactivation for both grape tomato and spinach. Sample size significantly affected the UV inactivation of Salmonella on grape tomato, but not on spinach. The effect of extending treatment time from 2 to 10 min was insignificant for almost all the UV treatments and the controls. The effect of UV intensity and treatment time on inactivation of Salmonella on spot-inoculated grape tomato and spinach was also determined. The most severe treatment used in this study, 30 mW/cm2 UV for 10 min, resulted in >4 log reductions of Salmonella dip- or spot-inoculated on grape tomato (200 g sample size and 190 RPM agitation speed) and 3.5 log reductions of Salmonella dip- or spot-inoculated on spinach (100 g sample size and 110 RPM agitation speed). We foresee that the UV appliance developed and evaluated in this study could be further fine-tuned and optimized to eventually construct a point-of-use UV appliance that can be used at home, cafeteria, restaurants, and hospitals for fresh produce decontamination and cleaning. The UV appliance could be an inexpensive and effective tool to improve fresh produce safety.

Quality of grape tomatoes in differents cultivation systems

Tomato is a fruit rich in bioactive compounds like lycopene, vitamin C and phenolic compounds. However, cultivation conditions can influence the concentration of these substances. In this study, the objective was to analyze quality characteristics of tomato fruits in different cultivation systems. The following characteristics were evaluated: pH, soluble solids content, total acidity, relationship between soluble solids content and total acidity, instrumental color parameters (L *, a *, b *, chroma and hue), texture, bioactive compounds (total carotenoids, lycopene, total phenolic compounds and vitamin C) and antioxidant activity of grape tomato fruits grown in a greenhouse in different systems (soil x substrate). A completely randomized design was used, with two treatments and four replications. The analysis were performed by official methods and in triplicate. The pH, soluble solids, texture, color, lycopene, vitamins C and antioxidant activity were not affected by the cultivation system used. However, grape-type tomatoes grown in substrate showed higher levels of carotenoids (36.31 µg.100 g-1 fresh matter), phenolic compounds (68.37 mg GAE.100 g-1 fresh matter) and ratio between total soluble solids and total acidity (17.90), and lower total acidity (0.58% citric acid 100 g-1), which represents a nutritional, sensorial and functional advantage for the consumer.

Physicochemical Properties and Shelf-Life of Regular-Fat Sausages with Various Levels of Grape Tomato Powder Prepared by Different Drying Methods.

This study was aimed to investigate the physicochemical properties, texture, and antioxidant, and antimicrobial activities of regular-fat sausages (RFSs) mixed with 0.25 and 0.5% of oven-dried and freeze-dried grape tomato powder (GTP, 150 μm) during storage at 4°C. RFSs were made by six treatments that included: control (CTL), REF (sausages with 0.1% ascorbic acid alone), F1GTPSs (F1) and F2GTPSs (F2) (sausages with 0.25% and 0.5% freeze-dried GTP), and O1GTPSs (O1) and O2GTPSs (O2) (sausages with 0.25% and 0.5% GTP oven-dried at 100°C). Sausages with added oven-dried grape tomato powders (OGTPs) showed decreased pH, lightness (L*), total plate count (TPC), and thiobarbituric acid-reactive substances (TBARS) compared to the sausages mixed with freeze-dried GTP (FGTPSs), but also had the highest redness (a*) and yellowness (b*) values among the treatments. With increasing levels of GTP, the hardness and chewiness of the sausages gradually decreased and these were decreased more in the FGTPSs (F) than in the OGTPSs (O). Compared to the FGTPSs, OGTPSs had higher antioxidant and antimicrobial activities, which extend the shelf-life of meat products. Application of OGTP to RFSs resulted in higher lipid antioxidant, antimicrobial activities, improving physicochemical properties and extended the shelf-life.

DEFICIT IRRIGATION OF SUBSURFACE DRIP-IRRIGATED GRAPE TOMATO

ABSTRACT Agriculture is one of the segments that most uses water and developments have been made to save irrigation water. Deficit irrigation is a technique that can contribute to production and water saving in agriculture. This study aimed to evaluate the viability of deficit irrigation in tomato production irrigated by subsurface drip in a greenhouse and estimate water saving. The experiment was conducted at the CCA/UFSCar, in Araras, Sao Paulo, Brazil, with grape tomato cultivation. It consisted of three treatments, 100 % water depth and deficit irrigation (75 and 50 % of water depth), with a randomized block design. Irrigation management was performed using mean soil moisture data collected through TDR probes installed in each treatment. Tomato plants were cultivated for 137 days and conducted vertically with one stem and six bunches. Fruit size, number and mass of fruits per plant, fruit pH and soluble solids were attributes measured and analyzed weekly. The deficit irrigation of 50 % treatment presented lower values in all attributes evaluated and 90.6 % of water saving. The 75 % treatment showed lower value only for pH and fruit diameter and 70.4 % of water saving. Deficit irrigation of 75 % was viable for tomato cultivation in greenhouse and for water saving in crop cycle.

Two Generally Recognized as Safe Surfactants plus Acidulants Inactivate Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in Suspension or on Dip-Inoculated Grape Tomatoes

Contamination of fresh produce with the foodborne pathogens Salmonella enterica, Listeria monocytogenes, and Escherichia coli O157:H7 continues to be problematic, resulting in outbreaks of foodborne illness and costly corporate recalls. Various individual concentrations of citric or lactic acids (0.35 to 0.61%) or isopropyl citrate (0.16 to 0.54%) combined with two generally recognized as safe surfactants, 0.025% sodium-2-ethyl-hexyl sulfate and 0.025% sodium dodecylbenzene-sulfonate, were tested against these three pathogens in suspension and when inoculated and dried on the surface of grape tomatoes. The efficacy of sodium hypochlorite (NaClO; at 46 ppm) was also evaluated under dirty and clean conditions in suspension after addition of 0.3 or 0.03% bovine serum albumin, respectively, as an organic load. NaClO (46 ppm) inactivated the three pathogens in suspension by <0.76 log CFU/mL after 5 min in the presence of 0.3% bovine serum albumin, whereas 9 and 15 ppm of free chlorine inactivated the pathogens by 0.64 and 2.77 log CFU/mL, respectively, after 5 min under clean conditions. Isopropyl citrate (0.16% acidulant) plus 0.05% total concentration of the two surfactants inactivated the pathogens in suspension by up to 7.0 log CFU/mL within 2 min. When applied to grape tomatoes for 2 min, 0.54% isopropyl citrate plus 0.025% concentrations of each of the two surfactants reduced Salmonella, E. coli O157:H7, and L. monocytogenes by as much as ca. 5.47, 4.89, and 4.19 log CFU/g, respectively. These reductions were significantly greater than those achieved with 49 ppm of free chlorine. Citric acid and lactic acid plus surfactant washes achieved greater inactivation than water-only washes, reducing Salmonella, E. coli O157:H7, and L. monocytogenes on tomatoes by up to 4.90, 4.37, and 3.98 log CFU/g, respectively. These results suggest that these combinations of acidulants and surfactants may be an effective tool for preventing cross-contamination during the washing of grape tomatoes, for reducing pathogens on the fruit itself, and as an alternative to chlorine for washing fresh produce.