Effect of dried and vinegar flavored squid products on acid resistance of Salmonella Typhimurium and Staphylococcus aureus

To examine the risk of food poisoning due to the consumption of contaminated processed squid products, we investigated the effects of selected low water activity, aw (about 0.55), and low pH (about 4.3) squid products on Salmonella Typhimurium and Staphylococcus aureus acid resistance in culture broth adjusted to pH 2.5 and 3.0. Pieces (0.3 g) of both squid products protected S. Typhimurium in 10 ml of acidified BHI broth adjusted to pH 3.0 and pH 2.5. S. aureus was also protected by the products in BHI broth adjusted to pH 3.0. Interestingly, S. aureus cell survival when spot inoculated on the low pH squid and transferred to broth was greater than for cells inoculated in the broth with pre-added low pH squid. These rapid protective effects on pathogens might result in longer survival in foods and allow introduction to the intestine through gastric acid resistance.

► S. Typhimurium and Staphylococcus aureus are causes of dry food poisoning.
► S. Typhimurium showed acid (pH 2.5 and 3.0) tolerance with dried and vinegar flavored squid.
► S. aureus showed acid tolerance by pre-inoculation on vinegar flavored squid.
► These rapid protective effects might result food poisoning through gastric acid resistance.