Full text
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| Author(s): |
Fabio Henrique Takahashi
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2011-09-01 |
| Examining board members: |
Paulo Fernando Machado;
Marcos Veiga dos Santos;
Thais Maria Ferreira de Souza Vieira
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| Advisor: | Paulo Fernando Machado |
| Abstract | |
This study aimed to employ statistical process control (SPC) as a tool to improve milk quality. The first objective of the study was to evaluate SPC as tool to identify non-natural variation of milk quality that are possible to be manipulated. In this study, data on milk production, somatic cell count (SCC), and total bacterial count (TBC) of 384 farms were used, provided by database of Clínica do Leite ESALQ/ USP in 2009. Natural effects (time of year and milk production) trough SCC and TBC variation were evaluated, and additionally, control charts for score cell somatic (SCS) and total bacterial count transformed (TBCt) were built aiming to identify sources of non-natural variations in a group of four farms. The variability of information was evaluated trough standard deviation estimator (sigma), calculated with basis of moving range. It was observed that time of year influenced significantly SCS and TBCt. The control charts, in each period, indicated signs of non-natural variation in SCS and TBCt in the group of herds evaluated. Furthermore, the control charts characterized the farms in statistical process control. The second study aimed to use SPC as a tool for identification and rating farms with larger probabilities of infraction on quality standard used by industry. Data of SCC and TBC from 452 farms, from January 2009 to March 2010, were used. The proportion of violation in quality standard, regarding the limits of SCC = 4000,000 cells/ mL and TBC = 100,000 CFU/ mL was calculated. Capability indices (Cpk) were calculated and farms were categorized into four classes of Cpk means and indices. Farms that presented larger means and deviation shoed superior frequencies of violation. Herds with means below the proposed limits of SCC and TBC represented, respectively, 25.05 % and 97.78 % of farms. However, proportion of farms that delivered milk consistently within the standards of quality evaluated (Cpk 1) represented 4.65 % and 35.17 % of farms for SCC and TBC, respectively. Therefore, application of SPC on farms is an additional tool for monitoring milk quality produced, the index Cpk can be used, by industries, associated with the current models to characterize milk quality from farms, since it identifies herds more consistent in producing quality-standard milk. (AU) | |
| FAPESP's process: | 09/02977-6 - Evaluation of the performance of automatic samplers to collect samples of milk to pay for quality. |
| Grantee: | Fabio Henrique Takahashi |
| Support Opportunities: | Scholarships in Brazil - Master |