Automated turbidimetry for rapid determination of the bacteriological quality of raw meat and processed meat products

Abstract

A fully automated centrifugal spectrophotometer for turbidimetric measurements linked to a computer for data processing was used to record and analyze growth of different types of bacteria associated with spoilage of raw meat and processed meat products (sliced meat for sandwiches) in order to predict bacterial counts. Media for this specific analysis were developed to enumerate total viable count, lactic acid bacteria, Brochothrix thermosphacta and Pseudomonas spp. Correlation coefficients of -0.91 to -0.97 were obtained between the conventional plate count technique and the turbidimetric method (linear regression). Lactic acid bacteria in the range 10 3 to 10 9 cfu/g could be detected within 48 h, whereas total viable count, Brochothrix thermosphacta and Pseudomonas spp. generally could be detected within 24 h. Counts exceeding 10 7 cfu/g could be detected within 6 h.