Antibiofilm Strategies in the Food Industry - Antibiofilm Agents: From Diagnosis to Treatment and Prevention - page 355

and contamination still occur. In recent years several physical and chemical
methods have been developed to avoid/control biofilm formation and will be
discussed below.
4 Current Approaches
4.1 Chemical Disinfection
To obtain an efficient disinfection, surfaces should be properly cleaned. However,
disinfection can be affected by environmental conditions such as temperature, pH,
concentration, contact time, soiling and type of surface or medium to be disinfected,
and the presence of organic substances including fat, carbohydrates and protein-
based materials (Møretrø et al. 2012 ). Disinfectants may also differ in their ability
to kill target microorganisms. There is a wide range of chemical disinfectants,
which can be divided according to their mode of action: oxidizing agents including
chlorine-based compounds, hydrogen peroxide, ozone and peracetic acid, surface-
active compounds including quaternary ammonium compounds (QACs) and acid
anionic compounds, and iodophores (van Houdt and Michiels 2010 ). Chlorine-
based compounds, such as hypochlorite, are widely used in the food industry
because chlorine has a broad spectrum of activity, acts fast, and is usually cheap.
This compound has been shown to be highly effective against biofilms (Tot ´
et al. 2010 ; da Silva et al. 2011 ) and has greater efficacy in low pH than alkaline
pH environments (Ara ´ jo et al. 2011 ).
Disinfectants containing hydrogen peroxide or peracetic acid are regarded as
environmentally friendly because they decompose into oxygen and water (or acetic
acid). Hydrogen peroxide affects the biofilm matrix, has been found to be effective
against biofilm cells and is widely used in disinfectants (Robbins et al 2005 ;
Shikongo-Nambabi et al. 2010 ). Hydrogen peroxide-based disinfectives also have
a broad spectrum of activity and act fast. Peracetic acid has the advantage of being
relatively stable in the presence of organic compounds compared to other disinfec-
tant types. Several studies have reported its efficacy against biofilms. For instance,
Cabe¸a et al. ( 2008 ) showed that 0.50 % w/v peracetic acid reduced 24 h-old
L. monocytogenes biofilms by 5 log. Similarly, Frank and coworkers ( 2003 ) demon-
strated that 2.0 mL/L peracetic acid reduced L. monocytogenes biofilms more than
6 log on stainless steel in the presence of fat, protein, and soil after 10 min of
exposure.
Ozone is regarded as an environmentally friendly disinfectant as it rapidly
disintegrates into water and oxygen. Unfortunately, its instability can cause it to
react and disintegrate before reaching the target organism. However, ozone is a
potent antimicrobial agent, which can be used against bacteria, fungi, viruses,
protozoa, and bacterial and fungal spores (Khardre et al. 2001 ).