Description
Mickle and Breed initially reported the inclusion of tomato juice in medium utilised for the cultivation of lactobacillus species1. Kulp, whilst researching the effects of tomato juice on bacterial growth, found that the growth of L. acidophilus was particularly enhanced using this medium, with large,white colonies, more characteristic than those isolated on other media.2 Later, Kulp and White modified the formulation, resulting in higher quantitative bacterial counts3.
The formulation of Amyl Tomato Juice Agar, AM199, is based on the modification of Kulp and White. Tomato Juice Agar was extensively used by the food and dairy industries for the enumeration of lactobacilli using the direct pour plate technique. However, it is less sensitive than LBS Agar (Lactobacillus Selective Agar) of Rogosa et al., which has replaced its use in some laboratories. Selectivity can be improved by lowering the pH to 5.0 by the addition of approx 1 ml of sterile 10% lactic acid per 100 mls. This is particularly useful when saliva samples are involved.
