# Novel Techniques for Microbiological Safety in Meat and Fish Industries
## 6 Non-Thermal Preservation Techniques
### Pulsed Light  
Pulsed light (PL) is a technique that uses short light pulses to inactivate microorganisms on food surfaces. The UV spectra of light is responsible for the antimicrobial effect, as it damages the DNA of microorganisms [90]. In the PL treatment, 1-20 light flashes per second with energy ranging from 0.01 to 50 J/cm\({}^{2}\) are used [91]. The microorganisms on the surface of the food and the packaging material are inactivated by these pulses. UV light causes physicochemical changes in microbial DNA, which damages the genetic information and leads to impaired replication and gene transcription, as well as cell death of microbes [90]. There are various potential uses in the meat industry, such as carcass (skin and meat) decontamination, better safety of fresh food products such as beef and tuna carpacio, decontamination of knives and equipment after contact with meat and meat products, as well as sliced fermented sausages. Pulsed light intensity can cause changes in the sensory properties of meat, particularly color and aroma.  
There are some limitations to the treatment's intensity, which should be optimized based on the number of flashes, voltage, spectral range, and distance between the product and the light source. Another concern is the financial aspect due to the requirement for specific equipment [90]. After PL treatments, the initial microbial count was reduced by approximately 2.0 log CFU/mL. _Listeria monocytogenes_ and _Salmonella enterica_ were the most commonly studied microorganisms in fish after PL treatments. The _L. monocytogenes_ count was reduced by 0.9-2.24 log CFU/mL in meat and 0.7-2.4 log CFU/mL in fish/seafood, whereas _S. enterica_ had a value of 2.0 log CFU/mL [91]. PL treatments (0.7, 2.1, 4.2, 8.4, and 11.9 J/cm\({}^{2}\)) were used to improve the safety of beef. The results showed a considerable reduction in the initial microbial count (1 log CFU/cm\({}^{2}\)) of samples inoculated with _Vibrio parahaemolyticus_, _E. coli_, _L. monocytogenes_, and _Salmonella Typhimurium_ after PL treatment at 8.4 and 11.9 J/cm\({}^{2}\), as well as a marked enhancement in the food safety of beef [92]. It was also observed that PL treatment was equally efficient in inactivating all pathogens inoculated on the surface of fermented salami slices (_E. coli O157_, _Staphylococcus aureus_, _L. monocytogenes_, and _Salmonella_ spp.), with a highest possible inactivation of microorganisms of 2.2 log CFU/g [93]. The changes in meat sensory quality caused by PL varies widely depending on the species of animal, type of meat, and PL dose used. PL had little effect on the sensory properties and instrumental color values of dry cured and fermented meat products [92].  
Pulsed light is specifically used for microbial spoilage control in meat and pork. Evidence has reported that pulse light application in range of 0.52 to 19.11 J/cm\({}^{2}\) caused a significant load reduction in _Salmonella Typhimurium_ count ranging from 1.73 to 3.16 log reduction, while for _Yersinia enterocolitica_, load reduction ranged from 1.48 to 4.37 log [94].