TOMATO PACKING TECHNOLOGY
The most commonly used indicator of fecal contamination in fresh produce production and packing is Escherichia coli. In depth analysis of the prevalence and characteristics of naturally occurring E. coli strains in these environments is important because it can (1) serve as an indicator of sources of fecal contamination; and (2) provide information on strain pathogenicity, persistence, and other defining characteristics such as multidrug resistance. In this study, we analyzed 341 E. coli strains isolated from the jalapeño pepper, tomato and cantaloupe farm environments, in Northeast Mexico. Strains were isolated from produce, farmworkers' hands, soil and water. Pathotypes, genotypes, biofilm formation and antibiotic resistance were characterized. Phylogenetic subgroups and identification of diarrheagenic E. coli were determined by PCR; biofilm formation was quantified using a plate-based colorimetric method. Antibiotic resistance was analyzed by the Kirby Bauer diffusion disc method. Most isolates (N = 293, 86%) belonged to phylogenetic group A. Only four isolates (1.2%) were diarrheagenic: EPEC (N = 3) and ETEC (N = 1). Antibiotic resistance to tetracycline (23.2%) and ampicillin (19.9%) was high, and only 3.5% of the strains presented resistance to >5 antibiotics. Biofilms were produced by most strains (76%), among which 34.4% were categorized as high producers. The presence of antibiotic resistant E. coli strains that may contain gene markers for pathogenicity and which can form biofilms suggests potential health risks for consumers.
TOMATO PACKING PROCESS
A fuzzy mathematical program is formed when the strict requirements within a mathematical program (objective coefficients, right-hand-side values, inequality conditions, etc.) are fuzzified. In general, such fuzzifying is appropriate for situations where the values or conditions are subjects of perception. In tomato packing, uncertain elements attributed to human perception are quite common. Such elements include harvest time, tomato packing rate, and shortage cost. In this paper, we first provide an LP formulation to determine the production schedule for a fresh tomato packinghouse. Then the corresponding fuzzy elements are fuzzified into a fuzzy model which is solved using an auxiliary model (mixed 0–1 LP). Using real-life data, we compare the cost obtained from the LP to that from the fuzzy model. It is found that the cost from the former is substantially higher. We observe that the rigid requirements in the LP results in an unrealistic optimal solution, while the fuzzy programming seeks to realize a desirable solution (as perceived by the user) by relaxing some resource restrictions. It is further observed that such opportunistic relaxation of constraints to achieve a better solution is typical of decision-making behavior in tomato packing.
TOMATO PACKING EQUIPMENT
The physical and mechanical properties of tomato fruits are very pertinent and crucial in the design of mechanised equipment for harvesting, cleaning, sorting, grading, storing and packaging for transportation from farms to processing plants or market centres. The concept of physical and mechanical properties can be applied to prevent the degradation of tomato fruits during harvesting and processing. The objective of this research is to establish the physical and mechanical properties of locally cultivated tomatoes (Eva F1 variety) in the Bono Region of Ghana. The 3-Dimensional linear characteristics of the samples obtained from linear measurement lead to the conclusion that Eva F1 is spherical and as a result it can undergo both sliding and rolling motions because of the aspect ratio which is between 77.54 to 95.18 and sphericity values above 83.00. The linear measurements also revealed that handling and sorting devices should have an aperture size between 34 and 77 mm for outlet or inlet dimension for mechanisation. An ELE compression machine was used to determine the firmness of different grades of Eva F1 tomatoes (red and yellow). An average compressive force of 16.88 N was found to cause fracture to the cell wall of a ripe (red) tomato while the yellow grade experienced an average force of 21.77 N. An inclined plane was used to determine the coefficient of friction for two different wooden surfaces (smooth and rough wawa boards). Average coefficient of friction values higher than 0.22 are recommended for mechanised material handling equipment and 0.21 or lower for packing boxes suitable for transportation. The research also showed that the best stage for the transportation of tomato is when they are at the yellow stage with low coefficient of friction and can absorb more energy before rupture.