Summary The combination of pulsed electric fields (PEF) and texturizing and antifreeze agents on quality retention of defrosted potato strips were studied. Potato strips (10 mm thickness, 100 g) were placed in different solutions (1% w/v) of CaCl2, glycerol, trehalose as well as NaCl and sucrose, treated with PEF (0.5 kV cm−1, 100 pulses, 4 Hz). Then, all the samples were soaked in the same solutions for 10 min. After draining, samples were packed into polypropylene pouches and stored at −18 °C for 12 h. Samples were thawed out at room temperature (20 °C) in 3 h. Untreated controls and PEF treated control samples were also frozen and thawed in similar conditions. To assess the potato strip quality, the thawed samples were analysed for moisture content, weight loss, firmness and colour attributes. The results indicate that PEF treatment by itself is not a suitable pre‐treatment method for frozen potato strips and should be assisted by CaCl2 and trehalose treatment to prevent softening after defrosting. Firmness analyses determined that application of PEF alone results in 2.38 N. However, PEF in combination with CaCl2 and trehalose result in 2.97 N and 2.99 N, respectively, which are both significantly firmer than the samples solely treated with PEF. CaCl2 and trehalose were effective in not only maintaining the structural integrity of the cells, but also retaining colour attributes. The L* value was found to be higher (P < 0.05) in CaCl2 and trehalose treated samples (58.95 and 57.21, respectively), as compared to PEF treated samples (53.97) denoting a darker colour. Application of CaCl2 and trehalsoe in combination with PEF also resulted in significantly less weight loss after thawing.

The interaction of pulsed electric fields (PEF) with different cryoprotectant and texturizing agents in quality retention of carrot discs was analysed. Increasing the permeability properties by PEF may lead to better accessibility of intracellular materials to freezing and thus reducing the freezing time, leading to better maintaining the texture after thawing. Carrot discs of 5 mm thickness were immersed in different solutions of CaCl 2 , glycerol, trehalose and tap water, and subsequently were treated with PEF (1 kV/cm, 100 pulses, 4 Hz). Then, the samples were drained and packed along with a control group in separate prepared polypropylene pouches. All the samples were frozen at À18°C for 24 h and thawed during 3 h at ambient temperature (20°C) the following day. The quality of the thawed carrot discs was certified by measuring weight loss, firmness, microscopic studies and CIE colorimetric attributes. All the PEF-treated samples, no matter what solution they were soaked in, could significantly (P < 0.05) maintain the firmness as well as colour attributes. However, it was deducted that application of CaCl 2 in conjunction with PEF can result in a firmer texture. Firmness analyses determined that application of PEF alone results in 5.84 N, while its combination with CaCl 2 leads to higher value of 6.63 N. Firmness in control samples was found to be 3.46 N. The SEM studies supported the results of firmness analysis and depicted more integrity in the cell walls of the samples treated with CaCl 2 and glycerol. The weight loss values varied among different samples, and the highest amount and lowest amount were reported in CaCl 2 and solely PEF-treated samples, respectively. There was no significant difference between the colour attributes measured in different groups including control sample (P > 0.05).

Food irradiation is over 100 years old, with the original patent for X-ray treatment of foods being issued in early 1905, 20 years after there discovery by W. C. Roentgen in 1885. Since then, food irradiation technology has become one of the most extensively studied food processing technologies in the history of mankind. Unfortunately, it is the one of the most misunderstood technologies with the result that there are rampant misunderstandings of the core technology, the ideal applications, and how to use it effectively to derive the maximum benefits. There are a number of books, book chapters, and review articles that provide overviews of this technology [25, 32, 36, 39]. Over the last decade or so, the technology has come into greater focus because many of the other pathogen intervention technologies have been unable to provide sustainable solutions on how to address pathogen contamination in foods. The uniqueness of food irradiation is that this technology is a non-thermal food processing technology, which unto itself is a clear high-value differentiator from other competing technologies.

Shiga toxin producing non-O157 E. coli strains such as E. coli O26 are responsible for a growing number of food-related illnesses in the United States and around the world. From food production to consumption, micro-organisms in foods experience dramatic pH fluctuations by organic acids introduced either during food processing or by inorganic acids in the stomach. Acid exposure induces specific metabolite accumulation in bacterial cells. Understanding the survival mechanisms of pathogenic micro-organisms by studying the metabolome would be helpful in introducing effective hurdles and thus ensuring food safety.