The efficacy of a citric acid-based organic sanitizer (organic Chico Wash) against Salmonella enterica serovar Newport and background microflora on fresh-cut celery and leeks was investigated. Three concentrations (1:10, 1:20 and 1:40) of Chico Wash were used. De-ionized water and 200 ppm chlorine were used as controls. For evaluating the efficacy against background microflora, fresh-cut celery or leeks were treated with sanitizers without an initial wash. For evaluating the efficacy against Salmonella, fresh-cut produce samples were initially washed and dip inoculated with 107 CFU/ml S. Newport. Samples were immersed in the sanitizer solutions for 2 min. Samples were taken for enumeration of survivors immediately after treatment and after storage at 4oC for 1, 3 and 6 days. Compared to controls washed in water at day 6, Chico Wash reduced Salmonella and background microflora by 0.7-1.5 and 1.2-2.6 log CFU/g, respectively. All three concentrations of Chico Wash showed 0.2-1.1 log additional reductions in Salmonella population compared to chlorine. At day 6, background microflora population on celery and leeks were 1-1.7 and 1.5-2.2 logs lower, respectively, than that on chlorine treated samples. The antimicrobial activity was concentration and storage time dependant.

Organic fresh produce sales have been increasing in recent years and ensuring safety of produce is important. We investigated the combined antimicrobial effects of plant essential oils and olive extract against Salmonella on organic leafy greens. Organic baby spinach, mature spinach, romaine lettuce, and iceberg lettuce were inoculated with antibiotic-resistant Salmonella Newport and dip-treated in phosphate buffered saline, 3.0% hydrogen peroxide, 0.1% cinnamon leaf oil and 3.0% olive extract or 0.1% oregano oil and 3.0% olive extract combination treatments. Leaves were sampled on days 0, 1, and 3 for enumeration. Treatment with both antimicrobials induced reductions in Salmonella population of up to 3.5-4 logs and 3-4.4 logs CFU/g on baby spinach and romaine lettuce, respectively. Salmonella population was reduced by 3 logs CFU/g on mature spinach. Cinnamon leaf oil and olive extract treatment yielded about 3.0 logs, while oregano oil and olive extract treatment yielded about 3.5 logs CFU/g reduction on iceberg lettuce. Compared to previously reported treatments with individual antimicrobials, the combination treatments had greater antimicrobial effect. The results showed that combination treatments involving essential oils and olive extract are a potential option for use as produce washes.

The relation between age gelation and proteolytic activity was investigated in this study, as proteolysis is considered to be one of the principal factors that cause gelation. Two different methods for measuring the proteolytic activity of milk samples were applied; the measurement of absorbance at 280 nm and the trinitrobenzene sulfonic acid (TNBS) method. The milk samples used were raw and UHT cow’s and goat’s milk. Proteolysis was also induced in UHT milk by inoculating cells of four different strains of Pseudomonas fluorescens into the milk and the changes taking place were observed. It has been found that the proteolytic activity of raw milk was not affected by a refrigerated storage for 10 days and only after this period it was gradually increased. The higher proteolytic activity of goat’s milk in comparison with cow’s milk during storage and its increased susceptibility to gelation were also established. Furthermore, the importance of storage temperature and the different effect of the four strains of P. fluorescens on proteolytic activity and pH of the UHT milk were shown. Finally, it has been demonstrated that there is a certain level of proteolytic activity in milk that leads to gelation when it is exceeded.

Forty six lines of oats from a program of breeding for low glycaemic impact were assessed by in vitro digestive analysis that allowed for theoretical effects of homeostasis on blood glucose concentrations. The oats were steamed and rolled (“rolled oats”; RO), and a portion made into porridge (PO) before in vitro digestive analysis. Carbohydrate digestibility was much greater and more rapid for PO than RO after 20 min digestion (RO, 16.9 g/100 g; PO, 42.5 g/100g on a dry oats basis) but similar after 120 min digestion (43 g versus 49.8 g), reflecting a high proportion of slowly digested starch in RO. Taking into account theoretical blood glucose disposal, RO was equivalent in glycaemic effect to 10.8 g of glucose and the PO to 17.5 g of glucose per 40 g serving (10.8 versus 17.5 g glucose equivalents). Based on published GI values, in vitro glycaemic analysis allowing for homeostasis provided realistic relative estimates of effects of processing on glycaemic properties of cereal foods.

The aim of the present study was to assess the effect of storage period and temperature on the nutritional quality, carotenoid and ascorbic acid contents of orange jam during storage for 30 days at 25 °C and 35 °C. For that purpose, special attention was paid to total sugars (TS), hydroxymethylfurfural (HMF), free amino acids (FAA), ascorbic acid (AA) and carotenoids. It was observed that storage conditions of jam led to statistical significant alterations for all monitored parameters. The decreasing parameter for jam at the end of storage under 25 °C and 35 °C, respectively, were 12.5% and 15% for TS, 50% and 59.5% for FAA, 23.5% and 29% for AA and 3% and 19% for carotenoids ; likewise, the increasing were 144% and 169% for HMF. The practical implications of this work are that the derived knowledge could be very useful to optimize storage conditions in order to improve the quality of these products.