Food preservation not always so easy

In Featured Post, Food Microbiology Journal Club by Prof Bob

One of the best examples of modified atmosphere packaged foods are the fresh salad greens and spinach products one finds in the produce section of the grocery. The reduced oxygen levels in these products, whether in bags or clam-shell packages, inhibits growth of Pseudomonas and other aerobic psychrotrophs.

As we will discuss in class, interventions used to enhance food preservation will often have untoward effects, such as selecting for microbes that do just fine under those conditions. In some cases, the outcome could even be worse.

In this 2019 paper, the authors showed that E. coli O157:H7 grew better in baby spinach packages in low oxygen conditions, as compared to when oxygen levels were higher. Thus, it is critical to fine-tune the oxygen levels such that growth of both aerobic spoilage microbes AND facultative pathogens is inhibited. Any ideas how one would do that?