沙门氏菌在不同环境下辣椒中的存活情况

Survival of Salmonella in Red Pepper under Different Environmental Conditions

研究沙门氏菌在不同温度和水活度辣椒中的生存情况。采用稀释涂布法检测沙门氏菌48 h内在不同水活度辣椒粉中的生长情况,及其能生长的最低水活度;分析在高、低水活度以及不同温度下沙门氏菌长期存活情况;利用扫描电镜及粘附强度实验观察沙门氏菌在高和低水活度辣椒块内外表皮粘附状况。结果表明48 h内各水活度沙门生长情况不同(p<0.05);在测试的辣椒粉中,最低能生长的水活度为0.92±0.01;长期存活实验中,沙门菌在37℃较25℃衰减得快,高水活度较低水活度衰减得快,最长存活时间为25℃低水活度下达到70 d;另外,高水活度辣椒块内表皮粘附情况特别严重,远大于外表皮。可见,沙门一旦污染了辣椒粉,其在辣椒中的长时间存活能力不可忽视,并且与常规思维不同的是低温保存其实有可能会延长沙门的寿命,从而带来食品安全隐患。而由于辣椒外表皮粘附情况没有内表皮严重,提示辣椒干完整保存有利于保证食品安全。

The survival of Salmonella at different temperatures and water activity（aw） levels was assessed in red pepper. The agar plate dilution method was used to detect the growth of Salmonella at different aw levels in red pepper over 48 hours to determine the minimum aw for growth. Scanning electron microscopy and adhesion strength tests were used to observe the adhesion ability of Salmonella to the inner and outer skins of red pepper at high and low aw values. The results showed that the growth of Salmonella differed significantly at different aw values in red pepper over 48 hours（p〈0.05）. In the test on pepper powder, the aw threshold for growth was determined as 0.92±0.01. In the long-term survival experiment, the rate of Salmonella population decline at 37 ℃ was higher than that at 25 ℃, the decline rate at high aw values was higher than that at low aw values, and the maximum survival time of Salmonella at 25 and low a℃w value was 70 d. In addition, at high aw value, the adhesion of Salmonella to the inner skin of pepper was more severe than that to the outer skin. Therefore, once pepper powder iscontaminated with Salmonella, attention should be paid to the long-term survival capability of the bacteria. In addition, in contrast to conventional thinking, low-temperature storage can actually extend the life of Salmonella, thus increasing food safety risk. The fact that the adhesion of Salmonella on the outer skin was not as severe as that on the inner skin suggested that the preservation of complete peppers is beneficial to ensure food safety.