Effect of Chlorine Dioxide Gas on the Properties of Packaging Materials and Effect of Chlorine Dioxide Gas to Maintain the Quality of Fresh Strawberries

ClO2 as an antimicrobial gas in the headspace of produce package is a relatively novel approach. Gaseous ClO2 is more effective than aqueous ClO2 and can be used in the headspace of fresh food packages. ClO2 gas can diffuse into product surfaces and films. As an oxidizer, it can react with and change polymeric package components, possibly affecting the product’s shelflife. This research studied effects of ClO2 gas treatments on produce packaging materials (APET, two PE types, Nylon). The treatment group (with ClO2) and the control group (without ClO2) of packaging materials were stored at room temperature and at three different relative humidities (49%, 84%, 99%) in sealed chambers. Dart drop, tensile tests, Tg, Tm, Tc, and water vapor transmission rate of materials were performed at six times over a 21-day period. A low dose (2 was a suitable application in these produce packaging materials. This research allows further experimenting with the literature on varying RH’s for the general application (ppm) of ClO2 on each polymer used for common fresh produce applications. This research also studied the use of ClO2 gas sachets to determine the effects on the sensory properties of strawberries. Conditions included typical strawberry storage systems (open pallet system under cold conditions (0-2 0C) and a controlled atmosphere storage system (99% RH, 0-2 0C). Both conditions were tested for 21 days with and without ClO2. ClO2 gas preserved strawberry quality with or without maximum RH. In the absence of 99% RH, ClO2 treated strawberries exhibited better quality than the untreated berries. High RH (99%) alone has significant quality retention of strawberries in a chamber system with or without ClO2. Either ClO2 or high (99%) RH plays a significant role in strawberry preservation in each other’s absence

Persistence of \u3ci\u3eEscherichia coli\u3c/i\u3e O157:H7 and \u3ci\u3eListeria monocytogenes\u3c/i\u3e on the Exterior of Common Packaging Materials

Acute gastroenteritis (AGE), a major cause of illness, results in 179 million AGE cases every year in the United States. AGE bacteria that have low-infectious dose include E. coli O157:H7 (\u3c10-100 cells) and L. monocytogenes (\u3c1000 cells). Because of their low-infectious dose and high environmental resistance, contaminated surfaces, such as the exterior surface of food packages, could be a source for disease transmission. Our aim was to determine the persistence of E. coli O157:H7 and L. monocytogenes on three packaging materials - oriented polyethylene terephthalate (OPET), oriented polypropylene (OPP), and nylon-6. Coupons (25 cm2) from each material were sterilized under ultraviolet light for 5 minutes. Spot and spread inoculation was done on treatment coupons with ca. 7 log CFU of a 3-strain-mixture of green fluorescent protein (GFP)-labeled E. coli O157:H7. All the coupons were incubated at Technical Association of the Pulp and Paper Industry-TAPPI standards. Surviving E. coliO157:H7 cells on duplicate coupons were recovered in saline at selected time intervals (0, 0.25, 0.5, 1, 2, 3, 5, 7, 14, 15 days). Surviving cells were enumerated on tryptic soy broth supplemented with ampicillin using the 3 tubes most probable number-MPN method described in the Bacteriological Analytical Manual. The experiment was performed in triplicate. The same procedure was carried out for 3-strain-mixture of rifampin-resistant (Rif)-L. monocytogenes using tryptic soy broth supplemented with rifampin for the MPN method. (GFP)-E. coliO157:H7 and (Rif)-L. monocytogenes survived on OPET, OPP, and nylon-6 for 15 days. The survival of E. coli O157:H7 was significantly different (p \u3c 0.05) from the survival of L. monocytogenes between days 0.5-1, 1-2, and 3-5. The survival of both bacteria on all three materials were not significantly different (p \u3e 0.05). E. coli O157:H7 and L. monocytogenes survived for over 2 weeks on OPET, OPP, and nylon 6, suggesting a highly contaminated outer surface of a food package could be a potential fomite for AGE outbreaks