Combination of hot-water surface pasteurization of whole fruit and low-dose gamma irradiation of fresh-cut cantaloupe

Evaluation of Hot Water, Gaseous Chlorine Dioxide, and Chlorine Treatments in Combination with an Edible Coating for Enhancing Safety, Quality, and Shelf Life of Fresh-Cut Cantaloupes

Fresh-cut cantaloupes have been implicated in numerous foodborne outbreaks of salmonellosis. Commercial aqueous wash treatments are limited in their ability to inactivate Salmonella enterica. Our objective was to evaluate the efficacy of hot water, gaseous chlorine dioxide, and chlorine on enhancing microbial safety and sensory qualities of fresh-cut cantaloupes. Cantaloupes were inoculated with an S. enterica cocktail (serovars Michigan, Mbandaka, and Poona) and treated with chlorine (200 ppm of free chlorine) for 40 min, 5 mg/L gaseous chlorine dioxide for 4.5 h, and hot water (76.1°C) for 3 min. Fresh-cut cantaloupes were prepared from treated whole cantaloupes and divided into two sets; one set of samples was treated with NatureSeal to evaluate its effect on shelf life and sensory quality and the second set (control) was packed without further treatment. Fresh-cut samples were stored at 4°C for up to 21 days. For the sensory quality parameters analyzed (color, water loss, and texture), the samples treated with NatureSeal had significantly better quality ( P < 0.05) than did the control samples. All treatments significantly reduced ( P < 0.05) the pathogen populations on the rind of the whole melons and on the fresh-cut samples prepared from the treated melons. All fresh-cut samples prepared from melons treated with hot water were negative for Salmonella throughout the storage period except for the samples treated with hot water and NatureSeal and evaluated on day 7. The fresh-cut samples prepared from melons treated with chlorine dioxide and chlorine were negative for Salmonella after 21 days of storage. These results provide a framework to producers of fresh-cut cantaloupes for the potential use of hot water as an intervention treatment in combination with NatureSeal for enhancing the microbiological safety and quality of this commodity.

Commercial thermal process for inactivating Salmonella Poona on surfaces of whole fresh cantaloupes

Outbreaks of salmonellosis by Salmonella Poona and listeriosis by Listeria monocytogenes have been associated with the consumption of cantaloupes. Commercial washing processes for cantaloupes are limited in their ability to inactivate and/or remove this human pathogen. Our objective was to develop a commercial-scale surface pasteurization process for enhancing microbiological safety of cantaloupes. Whole cantaloupes, surface inoculated with Salmonella Poona RM 2350, were stored at 32°C for 24 h prior to processing. Temperature-penetration profiles indicated that the surface temperature of the whole cantaloupe was 26 and 30°C below that of the hot water temperature after 2 min of immersion at 82 and 92°C, respectively. Hot water treatments at 92°C for 60 and 90 s reduced Salmonella Poona populations in excess of 5 log CFU/g of rind. Cantaloupes that were treated and stored at 4°C for 9 days retained their firmness quality and maintained nondetectable levels of Salmonella Poona as compared with the controls. Also, levels of Salmonella Poona on fresh-cut cantaloupe prepared from hot water-treated cantaloupes and stored for 9 days at 4°C were nondetectable as compared with the controls. These results indicate that surface pasteurization at 92°C for 90 s will enhance the microbiological safety of cantaloupes and will extend the shelf life of this commodity as well. The process parameter of 90 s or less falls within the commercial requirements of the whole-cantaloupe processor-packer industry.

Advanced methods for the elimination of microorganisms in industrial treatments: potential applicability to wastewater reuse

Because of the growing need to eliminate undesirable microorganisms in different industrial treatments, mainly in the food and agricultural sector and the pharmaceutical industry, a number of increasingly effective systems for disinfection to eliminate microorganisms have been devised. This article analyzes different methods to eliminate and/or significantly reduce the number of microorganisms in industrial contexts and in environmental engineering. Although, in the past, thermal treatments had been used most frequently for microbial elimination, the method is costly and has the disadvantage of modifying the organoleptic and/or physicochemical properties of the food products. For this reason, new technologies rapidly are being developed, such as high-intensity pulsed electric fields, high-pressure systems, ultrasounds, and irradiation, which effectively eliminate microorganisms without deteriorating the properties of the product. These emerging technologies are potentially applicable in the field of environmental engineering.

Use of chemical sanitizers to reduce microbial populations and maintain quality of whole and fresh-cut cantaloupe

Whole cantaloupes either not inoculated or inoculated with Salmonella Poona were submerged in water, 180 ppm of chlorine, acidified calcium sulfate (ACS: 1.2% Safe(2)O-ACS50), 1,000 ppm of acidified sodium chlorite (ASC), 80 ppm of peroxyacetic acid (PAA), and a combination of ACS and PAA for 10 min. Although only ASC and the combination of ACS and PAA significantly reduced the aerobic plate count of samples taken from the surface of whole cantaloupe (compared with samples taken from cantaloupe submerged in water only), all treatments reduced yeast and mold counts on the whole cantaloupe. However, none of the treatments of whole cantaloupes consistently reduced yeast and mold counts for the samples of fresh-cut cantaloupes. The aerobic plate counts for fresh-cut cantaloupe were reduced by 1 to 2 log CFU/g by sanitization of whole fruit with ASC, ACS, and the combination of ACS and PAA. The low bacterial population on the fresh-cut fruit was maintained during 14 days of storage at 4 degrees C. All treatments had a limited effect on the population of Salmonella, achieving no more than a 1.5-log reduction of the pathogen inoculated on the surface of the whole cantaloupes. Salmonella was nondetectable via direct plating (with a detection limit of 0.4 log CFU/g) in fresh-cut cantaloupes prepared from whole cantaloupes treated with any of the sanitizers. However, after enrichment, Salmonella often was detectable. Color, texture, soluble solids, pH, ascorbic acid, and drip loss of cut cantaloupes were not consistently affected by any of the whole-fruit treatments. Overall, treatments of whole cantaloupe with ASC, ACS, and the combination of ACS and PAA at the concentrations tested permitted a significant reduction in Salmonella and native microflora of whole and cut fruit; however, Salmonella still could be found in cut cantaloupes from all treatments.