This study determined the microbiological and chemical quality of ice produced and bagged on premises in retail establishments and in free-standing self-service ice vending machines in the state of Georgia and compared the results with that from ice produced by manufacturing companies monitored by the International Packaged Ice Association. Two hundred fifty bags of packaged ice samples were obtained from retail locations and self-service ice vending machines, along with 25 bags of packaged manufactured ice. Ice samples were melted within 24 h of collection and heterotrophic plate count SimPlates were used to detect heterotrophic bacteria present. Colisure and Enterolert assays were used to enumerate coliforms, nonpathogenic Escherichia coli, and enterococci. Membrane filtration coupled with enrichment was used to detect Salmonella and Listeria monocytogenes. Confirmation tests were done for presumptive-positive pathogens. None of the manufactured ice had unacceptable microbial levels. Six percent of the ice samples bagged at retail sites and from ice vending machines contained unsatisfactory levels of heterotrophs compared with the limits set by the International Packaged Ice Association (≥ 500 most probable number [MPN]/100 ml). Thirty-seven percent of these samples contained an unsatisfactory level of coliforms (≥ 1.0 MPN/100 ml), 1% contained nonpathogenic E. coli, and 13% contained enterococci (≥ 1.0 MPN/100 ml). One sample tested positive for the presence of Salmonella and another tested positive for Enterobacter agglomerans. Ninety-five samples of packaged ice from retail establishments and vending machines (38%) had pH levels outside the acceptable range that can affect product flavor. Turbidity of three samples exceeded the acceptable level. No samples had unacceptable nitrate levels. Manufactured ice had better microbiological and chemical quality than ice packaged on the premises of retail locations and from self-serve ice vending machines.

The thermal resistance of Clostridium sporogenes PA 3679 ATCC 7955 was determined in soymilk (pH 7) and 0.1% peptone water (pH 7) by the capillary tube method. In the continuous flow high-pressure throttling, the temperature of soymilk increased due to instantaneous pressure release and the additional heat was supplied by a heat exchanger to achieve the set temperature. The soymilk was immediately cooled after a short preset hold time to below 40 degrees C. A significant increase in the heat resistance was observed in C. sporogenes spores when heated in soymilk in comparison to 0.1% peptone water. The D(121)-value for spores in soymilk was approximately 3-folds higher than peptone water. The z-value was also much higher in soymilk as compared to that in 0.1% peptone water. Continuous flow high-pressure throttling (HPT) from 207 or 276 MPa to atmospheric pressure reduced the microbial populations in inoculated soymilk up to 6 log cycles when the holding times were 10.4, 15.6, and 20.8 s and the process temperatures were 85, 121, 133, and 145 degrees C, respectively. The sporicidal effect increased as the operating pressure, time, and temperature were increased. More injured spores were found at 207 MPa than at 276 MPa, indicating that lower pressure caused cell injury whereas high pressure caused cell death.

Whole chicken breast was injected with potassium bicarbonate (PB), sodium bicarbonate (SB), and potassium lactate (K-lactate) and salt, alone or in combination at different concentration levels. The objectives were to 1) investigate the effects of different concentration of PB, SB, and PL on instrumental color, water-holding capacity (WHC), objective tenderness, expressible moisture, and moisture content and 2) evaluate whether sodium-containing ingredients can be replaced with potassium as a potential strategy to reduce total sodium content in the finished product. Results showed that chicken breast tissue marinated with SB and PB had greater moisture retention, display characteristics, and cooked product qualities than chicken breast tissue injected with water and the nonmarinated control. The L* values (lightness) did not change over the period of retail display and were not different compared to the control (P>0.05). The chicken breast enhanced with SB, PB, and K-lactate retained better retail display color than the controls (marinated with water and nonmarinated). Increasing the potassium bicarbonate concentration from 0.5 to 1.5% significantly improved the water-holding capacity (82.17 to 92.61%; P<0.05) and led to better cook yield (83.84 to 91.96%). Shear force values were lower at the 0.5% level for both SB and PB compared to the control. PB performed better on retail display and cooked meat quality than SB. This study suggests that chicken breast tissue can be marinated with KB as a healthier alternative to phosphate or SB.

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