Incidence and growth of Listeria monocytogenes in persimmon (Diospyros kaki) fruit.

The incidence of Listeria monocytogenes on persimmon (Diospyros kaki) surface of 'Fuyu' and 'Rama Forte' was evaluated during a 5-month-period (from March to July) of two seasons periods (years 2005 and 2006). The fruits were collected in wholesale and street markets and retail in Sao Paulo and Campinas City, Brazil. A total of 582 fruits were analyzed using the Bax System which is based on the Polymerase Chain Reaction. The ability of this pathogen to grow on the peel and pulp of the two persimmon varieties was also verified at different incubation periods at the temperatures of 10, 20 and 30 degrees C. The growth parameters were obtained by modeling the experimental data using the Gompertz function. The incidence survey showed the absence of L. monocytogenes. The growth curves showed that L. monocytogenes can grow on the peel as well as in the pulp of the two persimmon varieties studied incubated at 10, 20 and 30 degrees C and that low temperatures can reduce the generation rate but does not inhibit its growth.

[Occurrence of Listeria monocytogenes in raw milk, pasteurized type C milk and minas frescal cheese commercialized in Piracicaba-São Paulo]. / Ocorrência de Listeria monocytogenes em leite cru, leite pasteurizado tipo C e queijo minas frescal comercializados em Piracicaba-S.P.

Samples of raw milk, pasteurized C type milk and minas frescal cheese were analyzed for the presence of Listeria monocytogenes by a method developed for dairy products by Lovett (1) and by Lovett & Hitchins (2). A total of 20 samples of each product and from different commercial brands were analyzed, obtained from various retail stores in Piracicaba, SP. According to the pattern of sampling and methodology adopted, none of the samples of the aforesaid products was positive for the presence of L. monocytogenes or another species of the genus. It was possible to observe differences in the degree of selectivity of the selective media utilized, notwithstanding the LPM agar showing to be superior to MMA. Based on the literature and on the result obtained, becomes evident the need of a more suitable method for the detection and isolation of L. monocytogenes from foods, even when the patogen appears in low numbers, with purpose to obtain rapid, reliable and reproducible results.

Effect of calcium addition and acidification on the quality characteristics of canned okra (Hibiscus esculentus L).

A study was conducted on calcium chloride treatments of canned okra acidified by adding either acetic, citric, lactic, malic or tartaric acids or by lactic fermentation. The quality of the processed okra was determined by physical, chemical, microbiological and sensory analyses after a two month storage period at room temperature. The results indicated the possibility of processing high quality canned okra by small canneries, with low cost equipment and low energy requirements. The acidification procedures ensure minimal risk of botulism.

Wine industry residues extracts as natural antioxidants in raw and cooked chicken meat during frozen storage.

The effect of Isabel (IGE) and Niagara (NGE) grape seed and peel extracts on lipid oxidation, instrumental colour, pH and sensory properties of raw and cooked processed chicken meat stored at -18°C for nine months was evaluated. The pH of raw and cooked samples was not affected by the addition of grape extracts. IGE and NGE were effective in inhibiting the lipid oxidation of raw and cooked chicken meat, with results comparable to synthetic antioxidants. The extracts caused alterations in colour, as evidenced by the instrumental (darkening and lower intensity of red and yellow colour) and sensory results of cooked samples. In the sensory evaluation of odour and flavour, IGE produced satisfactory results, which did not differ from synthetic antioxidants. These findings suggest that the IGE and NGE are effective in retarding lipid oxidation of raw and cooked chicken meat during frozen storage.