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The effect of superchilled storage at -1°C on the microbial safety of oyster depurated with 0.2, 0.4, and 0.6 mg/L ozone was studied for 14 days. Fecal coliforms (4,100–16,000 MPN/100 g), Escherichia coli (1,500–3,650 MPN/100 g), Vibrio cholerae non-O1/non-O139 (13.0–102.0 MPN/g), and Salmonella spp. (2.270–3.035 × 103 CFU/g) were initially present in raw oysters. After 6 h depuration, fecal coliform counts decreased (P < 0.05) to 300, 20 and 20 MPN/100 g for 0.2, 0.4, and 0.6 mg/L treatments, while a 0.3 log decrease in control oysters was observed. Initial E. coli counts decreased (P < 0.05) in oysters to 50, 20, and 20 MPN/100 g for 0.2, 0.4, and 0.6 mg/L treatments, respectively. A 1 log reduction in V. cholerae non-O1/non-139 levels were observed in 0.4 and 0.6 mg/L-treatments after 2 and 4 h depuration. Salmonella spp. was not detected in oyster samples after 6 h depuration in 0.4 and 0.6 mg/L-ozone treatments. Considering the bacterial loads after depuration, at the end of superchilled storage the 0.4 mg/L-ozonated oysters attained lower (P < 0.05) fecal coliform levels (280 MPN/100 g) and E. coli counts in 0.4 and 0.6 mg/L-ozonated oysters (20 and 95 MPN/100 g, respectively). A 2-log decrease in V. cholerae non-O1/non-O139 levels on day 5 in 0.4 and 0.6 mg/L-ozonated oysters (< 0.3 MPN/g) was attained. V. cholerae non-O1/non-O139 counts in control oysters decreased 1 log on day 9 of superchilled storage. Salmonella spp. was not detected in ozonated and superchilled stored oysters. Levels of fecal coliforms, E. coli, Salmonella spp., and V. cholerae non-O1/non-O139 in non-ozone depurated oyster samples were higher than in control, 0.4 and 0.6 mg/L ozonated oyster samples during superchilled storage. The cumulative mortality rates after 14 days of storage for superchilled oysters (22.2%) was higher (P < 0.05) than 0.6 mg/L O3 (7.2%) and 0.4 mg/L O3 (5.8%) treatments, and control oysters (5.6%). pH values in control oysters decreased significantly (P < 0.05) throughout the storage period but not in oysters of both ozone treatments, indicating no detrimental effects on oyster survival. The results of this study suggest that superchilled storage enables ozonated shellstock oysters (0.4 mg/L-6 h) stored for 9 days to be safe human consumption.

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Mexico has five apicultural regions wich are defined according to their blooming period and geography. Varroa destructor Anderson and Trueman is controlled with pesticides and alternative treatments in all these regions. To determine the concentration-mortality response lines of V. destructor, bioassays with four pesticides that are used for its control in the Gulf of Mexico, Yucatan Peninsula and Central-Highland regions were conducted. The Burgerjon spraying tower was used to apply known concentrations of flumethrin, fluvalinate, amitraz and coumaphos. Lethal concentrations 50 (LC 50 ) and resistance indexes were calculated with Probit analyses. In the Gulf region, the resistance indexes were: flumethrin, 659.43; fluvalinate, 21.83; amitraz, 12.77; coumaphos, 1.49×. In the Central-Highland region: flumethrin, 243.43; fluvalinate, 19.04; amitraz, 8.56; coumaphos, 1.22 x. In the Yucatan Peninsula region: flumethrin, 4057.32; fluvalinate, 199.57; amitraz, 26.55; coumaphos, 3.93×. These results suggest a resistance to flumethrin, fluvalinate and amitraz, with similar values in migratory beekeeping regions, and higher values in the non-migratory region. Coumaphos remained effective in V. destructor populations of the Gulf and Central-Highland regions.

19 Aluen Cap is an oxalic acid (OA) formulation that Aluen Cap is an oxalic acid (OA) formulation 20 that shows promise as a control method for Varroa destructor. This work explores the use and 21 efficacy of Aluen Cap against V. destructor in Africanized honeybees in Veracruz Mexico, where 22 capped brood is always present across the year and acaricide resistance was a problem. Twenty-four 23 beehives were assessed over 42 days, a period of time associated with the liberation of OA from 24 Aluen Cap. The acaricide formulation shows significantly higher mean efficacy (92.1 %) than 25 control hives (36.5 %.). This test suggests the high value of the new oxalic acid formulation in