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The microbiological air quality at processing areas in a dairy plant was evaluated by using a one-stage air sampler, based on Andersen principles (impaction technique) and by culture settling plate technique, also known as sedimentation technique. Among these areas, milk reception, packaging, and pasteurization rooms were included. Rooms where cheese, yogurt, butter and "doce de leite" (Latin American typical treat made of concentrated milk and sugar) are made were also evaluated. For all processing areas, the numbers of mesophilic aerobic bacteria and yeast and molds recovered by air sampler were higher than 90 CFU•m-3-the maximum value recommended by American Public Health Association (APHA). In four of the six processing areas, the microbial numbers were higher than APHA's standard (30 CFU.cm-2 .week-1) according to culture settling plate technique. The results showed a difference (p<0.05) for the Staphylococcus aureus numbers (from <1.0 to 4.3 UFC•m-3) at processing areas. The numbers of microorganisms recovered by impaction technique were about 2 to 10 times higher than by sedimentation technique. The microorganism group determined at processing areas depended mainly on the technique. By the air sampler technique, it was observed the predominance of yeasts and molds and by sedimentation technique, of mesophilic aerobic bacteria. The increase of temperature at processing areas did not seem to affect the numbers of airborne microorganisms. On the other hand, the increase of air humidity showed a relation with the increase of microorganism numbers. The impaction technique should be chosen since it is better to recover airborne microorganisms, including pathogens.

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ATP-bioluminescence assay was used to evaluate the cleaning and sanitizing procedures of stainless steel milk contact surfaces. Surfaces of a raw milk transportation tank, a raw milk cooling storage tank, an equalization pasteurizing tank, a pasteurized milk storage tank and a pasteurized milk packaging tank, as well as a milk centrifuge were evaluated. The Relative Light Unit (RLU) using a commercial luminometer and mesophilic aerobic counts (CFU.cm -2 ) on surfaces were determined. There were no significant differences (p>0.05) in RLU on the assessed surfaces before and after the cleaning and sanitizing procedures. Also, there were no significant differences (p>0.05) in CFU.cm -2 on the surfaces before the cleaning and sanitizing procedures, whereas different bacterial numbers were found on surfaces after the hygiene procedures. The surfaces of the milk centrifuge, raw milk cooling tank and milk packaging tank showed the largest mesophilic aerobic numbers after the hygiene, reaching 2.21, 2.18, and 1.21 log10, respectively. The results demonstrated that there is no agreement among the techniques for classification of hygienic conditions of the evaluated surfaces, showing a non-direct relation between RLU and CFU.cm . The ATP-bioluminescence method showed that 100% of the surfaces were under inadequate hygiene conditions, while the plate count method detected only 50%, based on the APHA's recommendation, and 33%, based on the WHO's recommendation. High variations in RLU measurements were observed, suggesting the need for more than only one surface analysis. The ATPbioluminescence is not a direct replacement for microbiological testing, but provides complementary information and should be used as part of an integrated strategy.

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IntroduçãoA descoberta de novos componentes naturais em alimentos com propriedades anti carcinogênicas é atualmente um importante elemento na estratégia de prevenção do câncer. A maioria das substânci-as naturais que exibem atividade anti carcinogênicas é originada de plantas. Uma exceção é o ácido linoléico conjugado (CLA), um ácido graxo que está presente em altas concentrações na gordura do leite (PARODI, 1994).Ácido linoléico conjugado é um termo que descreve os isômeros geométricos do ácido linoléico. A conjugação da ligação dupla é geralmente nas posições 9 e 11 ou 10 e 12, podendo ser configuração cis ou trans (KEPLER et al., 1966;PARODI, 1977;IP et al., 1994 RESUMO -O objetivo deste trabalho foi verificar o efeito de fontes de lipídios (soja integral moída ou óleo de soja) adicionados à dieta sobre o perfil de ácidos graxos da gordura do leite, especialmente sobre o aumento do CLA. Foram utilizadas 6 vacas multíparas 7/8 holandês-zebu, 30 dias após o parto, com peso vivo médio de 500 kg e produção média de 20 quilos de leite ao dia. Os animais foram divididos em três grupos para recebimento das dietas (tratamentos), isoprotéicas e isoenergéticas, em que o tratamento controle continha 3% de extrato etéreo na ração total e os demais 7%. Os tratamentos contendo fontes de lipídios, quando comparados com o controle, diminuíram o percentual de ácidos graxos de cadeia curta e diminuíram os teores dos ácidos butírico, capróico, caprílico, cáprico, láurico, mirístico e o percentual de ácidos graxos saturados. Os mesmos tenderam, ainda, a reduzir os teores de ácido palmítico e palmitoléico e tenderam a aumentar o percentual de ácidos graxos insaturados e de cadeia longa. Por outro lado, esses tratamentos aumentaram o teor de ácido esteárico e tenderam a aumentar os teores de ácido oléico e CLA. O óleo de soja, comparado ao grão de soja moído, diminuiu os teores de ácido linoléico e linolênico e aumentou o CLA, tendeu a aumentar o teor de ácidos graxos não identificados e a diminuir os ácidos graxos saturados. Concluindo, a inclusão de óleo de soja na dieta, e não soja grão, aumenta o teor de CLA na gordura do leite.Palavras-chave: ácido linoléico conjugado, gordura, leite, lipídios, ração, vacas Effect of Lipids Supplementation in the Ration on Production of Conjugated Linoleic Acid (CLA) and Milk Fat Composition of Dairy CowsABSTRACT -The objective of this work was to verify the effects of lipid sources (ground soybean and soybean oil) added to the diet on the fatty acids profile of milk fat, specially in the increasing of CLA. Six multiparus 7/8 Holstein-Zebu cows, 30 days after calving, with average body weight of 500 kg and average milk production of 20 kg/day, were used. The animals were divided in three groups in order to receive isoprotein and isocaloric diets (treatments), in which control diet had 3% ether extract in total dry matter and the others 7%. Comparing to the control one, the treatments containing supplementar lipids, decreased the percentage of short chain fatty acids and decreased the content ...