Figure 3

Survival of bacteria (log CFU/PIF) in powdered infant formula during storage with spoon contaminated from artificial skin with high bacterial load (6 log CFU/hand) during storage. Data showed mean ± standard deviation (quantitative analysis; n = 6). Different capital alphabets (A–D) denoted on each data indicate significant differences of population levels between experimental time points within the same bacterial species (p < 0.05). The values in the parenthesis above the points indicate the results of enrichment tests as positive samples out of total trials (n = 6). The arrow bars (↓) indicate the general feeding interval (4 h) and use-by date of PIF suggested manufacturer (3 weeks).