Assessing the survival and sublethal injury kinetics of Listeria monocytogenes under different food processing-related stresses

Listeria monocytogenes Sublethal Injury and Viable-but-Nonculturable State Induced by Acidic Conditions and Disinfectants

“…Ahamad and Marth observed that acid-treated cells of L. monocytogenes needed less time for population decrease or injury after incubation at 35°C than at 13°C ( 43 ). Similarly, Siderakou et al reported that the injury levels of L. monocytogenes (Scott A strain) gradually increased within the first 8 h of exposure to Ringer’s solution at pH 3, adjusted with lactic acid, at 20°C, with the same inactivation pattern being observed at 4°C ( 44 ). Sibanda and Buys have also demonstrated extensive cell membrane damage and a high degree of injury in Listeria cells as a result of exposure to lactic acid ( 45 ).…”

“…This method relies on the inability of injured cells to grow on selective media ( 58 , 59 ). A concentration of 5% NaCl (wt/vol) was found to be the maximum noninhibitory concentration (MNIC) ( 44 ). Siderakou et al ( 44 ) reported that using TSAYE+5%NaCl (wt/vol) resulted in the peak of injury expressed as an increase in the time to form visible colonies, indicating that the concentration of NaCl in the selective plates poses an additional growth burden.…”

Viability, Sublethal Injury, and Release of Cellular Components From Alicyclobacillus acidoterrestris Spores and Cells After the Application of Physical Treatments, Natural Extracts, or Their Components

“…There are several targets for injuries; the most important ones are cell wall, cytoplasmic membrane or inner membrane, ribosomes, DNA, RNA, tricarboxylic acid cycle enzymes as well as many other enzymes ( 51 ). In addition, injured microorganisms are more sensitive to antimicrobial agents contained in selective media; thus, their growth could be delayed or inhibited on such substrates, but these microorganisms retain their pathogenicity and spoiling impact ( 52 ). Under favorable conditions, injured microorganisms can resuscitate and repair damage ( 52 ).…”

“…In addition, injured microorganisms are more sensitive to antimicrobial agents contained in selective media; thus, their growth could be delayed or inhibited on such substrates, but these microorganisms retain their pathogenicity and spoiling impact ( 52 ). Under favorable conditions, injured microorganisms can resuscitate and repair damage ( 52 ). Thus, the detection of sublethally injured bacteria is critical to quality control procedures performed in the food processing industry ( 53 ).…”

“…An excellent method available for detecting and enumerating sublethally injured bacteria is the application of selective culturing procedures, since sublethally injured bacteria become sensitive to salt or other selective compounds due to damage in their membrane and modifications of their permeability and lose their ability to grow on selective media ( 26 , 52 ). The amounts of salt for the medium to detect sublethal injury were chosen after a preliminary experiment aimed at assessing the NIC (not inhibitory concentration) of salt, that is, the highest concentration of salt not affecting the growth of not-injured A. acidoterrestris .…”