Biofilms in dairy processing

Endospores of Thermophilic Bacteria in Ingredient Milk Powders and Their Significance to the Manufacture of Sterilized Milk Products: An Industrial Perspective

“…The foulant appears to protect spores and vegetative cells during cleaning and thereby leads to contamination of the next production run. (49) (2) Rapid growth occurs in parts of the plant that operate in the optimum thermophile temperature growth range (e.g., 45-65 • C). Flint et al (43) reported doubling times of 19-32 minutes for Geobacillus in biofilms on the surface of stainless steel in a laboratory-scale reactor system.…”

“…The spores also survive well throughout the storage life of the powder (>1 year). (49) Without biofilm formation or fouling, the thermophile concentrations in milk powders would be insignificant. It is surface attachment and subsequent growth during long production runs that provide sufficient residence time for the organism to change from lag phase to exponential growth phase and for sufficient cells and spores to be produced and released into the process stream as a result of surface sloughing.…”

“…It is surface attachment and subsequent growth during long production runs that provide sufficient residence time for the organism to change from lag phase to exponential growth phase and for sufficient cells and spores to be produced and released into the process stream as a result of surface sloughing. (49) To control biofilm formation and surface fouling, and thereby minimize the contamination of milk powder by both vegetative cells and spores, powder manufacturers apply a variety of control strategies. Cream separator, heat exchanger, evaporator preheating, and evaporator run times must be of limited duration, product-contact surfaces (e.g., stainless steel, gaskets, and seals) need to be well maintained (47) and cleaning in-place (CIP) systems need to be optimized.…”

“…Cream separator, heat exchanger, evaporator preheating, and evaporator run times must be of limited duration, product-contact surfaces (e.g., stainless steel, gaskets, and seals) need to be well maintained (47) and cleaning in-place (CIP) systems need to be optimized. (49) Recycling of milk components or milk concentrate must also be avoided (or strenuously controlled), as it is well established that these materials can seed the process with contaminants. (50) New Zealand manufacturers have also adopted other strategies that assist in the control of thermophile growth, such as reducing cream separation temperatures from >50 to <45 • C and duplicating high-risk stages of the process (e.g., evaporator preheaters) so that the process flow can be alternated and mid-run CIP can be performed without interrupting overall production.…”

The Influence of Disinfectants on Microbial Biofilms of Dairy Equipment

“…The most important source of milk products microbial contamination is the technological equipment [1][2][3]. The results of scientific studies indicate that microorganisms survive on the technological equipment due to the extremely important property that is the ability to form biofilms [4][5][6]. A microbial biofilm -is a formation created of one or several species or genera of bacteria, fixed to the surface and surrounded by the matrix, synthesized by themselves [7,8].…”