This study aimed to investigate the acrylamide content in frozen food products after cooking. Twenty samples of bread (Group 1) and 30 samples of processed tuberous and corn vegetable products (Group 2) were selected. Acrylamide levels were quantified using liquid chromatography tandem-mass spectrometry (LC-MS/MS). The frozen food samples were heated using the air fryer cooking method according to the product packaging and were compared to ready-to-eat French fries (Group 3). The results showed that the acrylamide content was the highest in group 3, followed by that in group 2 and group 1. The acrylamide content of all the samples was found to be within the domestic recommended standard of 1 mg/kg. However, when the samples that exceeded EU benchmark level (0.5 mg/kg) were selected and cooked using the deep-fat frying method according to the product packaging, one of them showed the acrylamide content of 1.83 mg/kg, which exceeded the domestic recommended standard. The present study highlights the need for continued evaluation and management to reduce acrylamide contents in frozen foods, as increasing domestic exposure to acrylamide is concerning.

This study surveyed and compared the temperatures established in display stands and food surfaces for cold and frozen foods in large discount stores in Korea. The temperatures established in display stands for cold food ranged with 3.5 ± 1.8 ℃ as mean, minimum and maximum were 0 ℃ and 7 ℃ . However, the surface temperatures of cold food on sale ranged with 10.7 ± 2.9 ℃ as a mean, minimum 4.6 ℃ and maximum 18.4 ℃ . Totally, the surface temperature of cold food on sale was 7.2 ℃ , as a mean, higher than established in display stands for cold food in large discount stores in Korea. 53% of the surveyed cold foods were more than 10 ℃ in surface temperature and only 47% was less than 10 ℃ . The differences between temperatures were lowest in fruits, salads and vegetables, but highest in milk products. On the other hand, the temperatures established in display stands for frozen food showed a range with −20.7 ± 1 ℃ as a mean. However, the surface temperatures of frozen food on sale showed a range with −15.4 ±5 ℃ as a mean, minimum −28 ℃ and maximum −4.6 ℃ (included defrosting). The surface temperatures of frozen food,frozen meats, frozen processed foods and ice creams were −13.8 ℃ , −15.9 ℃ , and −16.8 ℃ , respectively. Only 32.3%of surveyed frozen foods showed less than −18 ℃ in surface temperature. In conclusion, the temperatures established on cold and frozen food display stands were less than those of cold and frozen food surfaces on sale. There was also much variation in food surface temperatures during cold and frozen food storage and sales. Therefore, a temperature management system technology use at the distribution level for cold and frozen foods will be developed.

From April to December in 2009, microbial investigation is accomplished for 100 frozen foods asked to microbial control team that corresponds with total aerobic viable bacteria, coliform group, Escherichia coli,Enterococcus spp. and antibiotic resistance patterns of Enterococcus spp. isolates are investigated. Average of total aerobic viable bacteria numbers is 4.3 × 10⁴CFU/g. Average of coliform group numbers is 4.3 × 10³ CFU/g. Average of Enterococcus spp. numbers is 1.8 × 10³ CFU/g. Escherichia coli from 100 frozen foods is not detected and detection rate is 0.0%. 22 Enterococcus spp. are isolated from 100 frozen foods. 12 of 22 Enterococcus spp. strains are identified as E. faecium. 7 of 22 Enterococcus spp. strains are identified as E. faecalis. 2 of 22 Enterococcus spp. strains are identified as E. gallinarum. 1 of 22 Enterococcus spp. strains is identified as E. hirae. Enterococcus spp. isolates show a high resistance to erythromycin, rifampin, tetracycline, ciprofloxacin, chlorampenicol, penicillin and a susceptibility to vancomycin, ampicillin, gentamicin, strepomycin, linezolid. 15 of 22 Enterococcus spp. strains are multi-resistant and the most frequent multi-resistant pattern is erythromycin-rifampin for 6 Enterococcus spp. strains.