食品包裝專業(yè)畢業(yè)論文外文翻譯--熱敷法凈化食品包裝材料（英文）

1、Journal of Industrial Microbiology packing machines; mould spores; Penicillium; humidityIntroduction humidity would be an option for the decontamination of packing materials where the main reason for concern is the Cons

2、umers are more and more demanding with respect to presence of moulds. the quality of food products. Therefore, products are often Spores of Penicillium species are frequently found on preserved by in-line short-time high

3、-temperature treat- packing materials even after thermoforming. For this reason ments. To prevent re-infection, the product then is and because of availability and ease of cultivation, spores packed aseptically. of Penic

4、illium roquefortii were used. The microbial load of the packing material must be low enough to assure that the acceptable rate of contamination is not exceeded [1]. Depending on the microbiological qual- ity, it may be n

5、ecessary to reduce the number of micro- Materials and methods organisms on the packing material before use. This may be achieved using hydrogen peroxide, heat, ultraviolet light, Materials or other treatments, either ind

6、ividually or in combination. The packing material comprised rectangular discs Treatment with hydrogen peroxide at elevated temperatures 35 × 45 mm made from a sheet of 550-?m thickness is by far the most common tech

7、nology used. Residues of (55 ?m of polyester (PETG) and 495 ?m of polystyrene) hydrogen peroxide, however, are undesirable; the accept- from Cobelplast, Lokeren, Belgium. The fungal spores able residual concentration in

8、the product packed is very were Penicillium roqueforti type CB2, obtained from low (?5 mg kg?1 in most countries). The use of hydrogen Wiesby (Niebu ¨ll, Germany), lot 735263. The talc was peroxide also requires saf

9、ety measures to protect personnel hydrous magnesium silicate, obtained from Lamers stirring bar be preferable. diameter 8 mm, length 50 mm. For products that do not allow the growth of bacteria, such as many acid produc

10、ts and products with a low water activity, it is often sufficient to inactivate moulds and Media yeasts. Moulds and yeasts, however, can be inactivated by The diluted malt extract agar contained agar (Difco) 20 g, temper

11、atures below 100°C provided the water activity is malt extract (Oxoid CM 57) 20 g, distilled water 1000 ml. high enough. The medium was autoclaved at 115°C for 15 min. The pep- The objective of the work reporte

12、d here was to determine tone salt solution contained peptone salt (Oxoid CM 733) whether the use of heat in combination with enhanced 9.5 g, of which peptone made up 1.0 g and NaCl made up 8.5 g, distilled water 1000 ml.

13、 The solution was autoclaved at 120°C for 20 min. The malt extract broth contained malt Correspondence: HLM Lelieveld, Unilever Research Laboratorium extract (Oxoid CM 57) 20.0 g, of which malt extract made Vlaardin

14、gen, PO Box 114 3130 AC, Vlaardingen, The Netherlands up 17 g and mycological peptone made up 3.0 g, distilled 2Current address: Asept, Rue des Docteurs Calmette et Gue ´rin, BP 49 water 1000 ml. The broth was autoc

15、laved at 115° C for 53020, Laval Cedex, France Received 9 September 1996; accepted 31 January 1997 10 min.Decontamination of food-packing materialD Raynaud and HLM Lelieveld328 Table 1 Inactivation of spores of P. r

16、oquefortii under various conditionsaTreatment ResultsTemperature inside Relative humidity Temperature of Time between No N R = No/N Log R (mean) sterilization chamber (%) heating plates heating plates (s) (°C) (

17、6;C)49 100 60 1 1410 2640 ?1 — 52500 74 600 ?157 100 70 1 1410 986 1.4 0.11 52500 42 700 1.262 100 80 1 1410 898 1.6 0.43 52500 13 550 3.81 3060 ?9 ?340 2.27 58700 1660 35 67 100 85 0 3060 31 99 1.77 58700 3040 191 1400

18、?1 ?1400 3.50 55300 11 5028 73 100 90 0 1400 ?1 ?1400 3.33 55300 19 29101 4410 ?5 ?882 3.98 55000 ?3 ?18333 76 100 95 0 4410 ?3 ?1470 3.48 55000 12 45831 5660 ?1 ?5660 3.91 53300 ?5 ?10 660 77 100 88 0 5660 ?1 ?5660 3.76

19、 53300 ?9 ?592230 100 3 4040 3050 1.3 0.11 4560 1830 2.5 32 120 3 0.36 82600 38 900 2.1Not measured 4040 300 13 27 150 3 1.75 82600 832 994560 ?3 ?1520 18 180 3 4.04 82600 ?4 ?20 650aIn all tests with 100% humidity the t

20、otal treatment time was slightly less than 3 s. Values of N are averages of CFU counts of three identical experiments, using discs of equal initial contamination. Log R was calculated after averaging the values of R from

21、 identical experiments; the ‘?’ signs have been ignored; thus the Log R values may be minimum values.Figure 3 The reduction in number of viable spores of P. roqueforti as a function of the temperature at high (a) and low